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A. Šupih-Kvaternik AN ENGLISH READER FOR FOOD TECHNOLOGY AND BIOTECHNOLOGY BOOK ONE

MANUALIA UNIVERSITATIS STUDIORUM ZAGRABIENSIS

Copyright © by Andrea Šupih-Kvaternik, Durieux, 2005 All rights reserved

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FACULTY OF FOOD TECHNOLOGY AND BIOTECHNOLOGY

UNIVERSITY OF ZAGREB, CROATIA

ENGLISH FOR SPECIFIC PURPOSES – ENGLISH FOR SCIENCE AND TECHNOLOGY

ANDREA ŠUPIH-KVATERNIK

AN ENGLISH READER

FOR FOOD TECHNOLOGY AND BIOTECHNOLOGY

BOOK ONE

WITH ENGLISH –CROATIAN DICTIONARY

REVISED EDITION, 2008




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REVIEWERS: Egon Bauman, PhD Sunita Bujas, prof. Shirley Tomlinson, MA, MS




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PREHRAMBENO-BIOTEHNOLOŠKI FAKULTET, SVEUČILIŠTE U ZAGREBU AND ENGLISH READER BOOK ONE AND BOOK TWO ZBIRKA RADNIH MATERIJALA S VJEŽBAMA I ENGLESKO-HRVATSKIM STRUČNIM RJEČNIKOM ZA STUDENTE PREHRAMBENO-BIOTEHNOLOŠKOG FAKULTETA , SVEUČILIŠTA U ZAGREBU Predgovor Studij pri Prehrambeno-biotehnološkom fakultetu u Zagrebu obuhvaća dva studija: studij Prehrambena tehnologija, sa smjerovima Prehrambeno inženjerstvo i Nutricionizam i studij: Biotehnologija, sa smjerovima Biokemijsko inženjerstvo i Biokemijska mikrobiologija. Radni materijali u udžbeniku “An English Reader for Food Technology and Biotechnology” - Book One and Book Two - zbirka su izvornih tekstova na engleskom jeziku iz raznih polja i područja znanosti obuhvaćenih studijima i smjerovima pri ovom fakultetu. Materijali su prilagođeni strukovnim potrebama studenata te njihovom predznanju općeg engleskog jezika, na koje se nadovezuje terminologija struke. Većina vježbi nadopunjena je strukovnim glosarom i raznim vrstama vježbi, od brzog pregleda i razumijevanja cjelovitog teksta, podjele teksta na smislene cjeline (scanning and skimming), traženja najvažnijih riječi ili rečenica u tekstu (key words and key sentences, paragraph topics) itd. Srukovni vokabular se obrađuje na samom tekstu i to na dva načina: a) iza svakog teksta ispisan je glosar sa strukovnim izrazima koji

se nalaze u danom tekstu b) od studenata se traži da sami izrade mali glosar vezan na

zadani tekst; time studente potičemo na samostalni rad s dvojezičnim i jednojezičnim rječnicima.

c) Svi primjeri i vježbe jezičnih, vokabularskih i gramatičkih struktura temelje se i uvježbavaju na samom izvornom engleskom tekstu, tj. jeziku struke.

d) Obadvije zbirke – An English Reader Book One (pisan za studente prve godine studija) i An English reader Book Two




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(pisan za studente druge godine studija) obiluju raznovrsnim materijalima i vježbama. Ovisno o smjeru studija i o razini poznavanja općeg jezika kao i jezika struke, odabiru se, uz obvezatne materijale, i dodatni materijali, koji se mogu obraditi na više načina: frontalno, sa svim studentima, radom u grupama, i pojedinačno sa studentima. Studenti mogu i samostalno odabrati stručni ili znanstveni tekst na izvornom engleskom jeziku, te ga obraditi i prikazati ostalim studentima i predavaču u obliku seminarskog rada.

Andrea Šupih-Kvaternik, prof.

viši predavač Prehrambeno-biotehnološki fakultet,

Sveučilište u Zagrebu, U Zagrebu, 2005.




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ZAHVALE Kao i svaki udžbenik, i udžbenici “An English Reader for Food Technology and Biotechnology” – Book One and Book Two – sa strukovnim rječnikom, rezultat su dugotrajnog i ustrajnog rada, od prikupljanja građe, stručnih i znanstvenih tekstova na izvornom engleskom jeziku, preko obrade i prilagodbe tekstova potrebama studenata i nastave pri Prehrambeno-biotehnološkom fakultetu u Zagrebu, sve do konačne pripreme teksta za tisak. Također je, tijekom izrade ovih udžbenika i rječnika, trebalo premostiti razne probleme terminologije, u nedostatku adekvatnih englesko-hrvatskih strukovnih rječnika. Isto tako bilo je veoma teško pronaći stručnjake koji bi bili spremni pomoći pri pisanju ovakvog udžbenika. Naime, veoma je malo profesora engleskog jezika, stručnjaka obrazovanih u smjeru humanističkih znanosti koji bi bili spremni sudjelovati u izradbi udžbenika pisanog za studente prirodnih znanosti. Isto tako teško bilo je pronaći stručnjake u prirodnim znanostima s tolikim poznavanjem problematike engleskog jezika koji bi mogli i htjeli, sa stručne strane, pomoći pri ovom radu. Osobno sam imala veliku sreću i čast jer su mi pri radu na ovom udžbeniku pomogle tri osobe, mislim da slobodno mogu reći, najkompetentnije za ovaku vrstu interdisciplinarnog rada. Neizmjerno sam im zahvalna na pomoći i podršci tijekom pisanja ovog udžbenika. Prvo bih se željela zahvaliti profesorici Suniti Bujas, mojoj mentorici, koja je utemeljila suvremenu nastavu jezika struke i zacrtala okvire i ciljeve nastave jezika struke pri Prehrambeno-biotehnološkom fakultetu u Zagrebu. Duboko sam joj zahvalna na podršci i pomoći. Od srca zahvaljujem na pomoći profesoru dr. sc. Egonu Baumanu, dugogodišnjem redovitom profesoru pri Prehrambeno-biotehnološkom fakultetu u Zagrebu, znanstveniku “prirodnjaku”, koji je istovremeno i jedinstvena “hodajuća” jezična enciklopedija. Iskreno zahvaljujem i mr. sc. Shirley Tomlinson, profesorici engleskog jezika u The English Language Centre u Brightonu, u Velikoj Britaniji. Iako istovremeno izvorni govornik i profesorica engleskog jezika, zbog rada na ovom udžbeniku i sama je morala duboko “uroniti” u, i za nju novo, polje vokabulara prirodnih znanosti, kao i zakonitosti nastave jezika struke. Zahvaljujem na podršci i pomoći Ministarstvu znanosti Republike Hrvatske, Odboru za udžbenike i skripta Prehrambeno-biotehnološkog fakulteta, Sveučilišta u Zagrebu, na čelu s prof. dr. sc. Senadinom Durakovićem i prof. dr. sc. Vladimirom Rapićem. Zahvaljujem i izdavačkoj kući Durieux na korektnom i profesionalnom odnosu. Posebno zahvaljujem mojem suprugu, Hrvoju Šupih - Kvaterniku, direktoru firme Kom-pa Konzalting, d.oo., na velikoj materijalnoj i logističkoj potpori pri izradbi ovog udžbenika.

Andrea Šupih-Kvaternik, U Zagrebu, 2005.




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POSVETA Pišući udžbenike " An English Reader – Book One and Book Two” moj jedini cilj bio je da mojim studentima pri Prehrambeno-biotehnološkom fakultetu približim stručni engleski jezik i da im olakšam čitanje i razumijevanje stručne i znanstvene literature, kao i pisanje sažetaka na engleskom jeziku, te, općenito komuniciranje u svijetu znanosti na engleskom jeziku. Biti će mi veliko zadovoljstvo ako sam u tome uspjela. Svim mojim sadašnjim I budućim studentima, kojima su ovi udžbenici namijenjeni, želim puno uspjeha u njihovom radu. Knjige posvećujem mojim kćerkama Ivani i Jani, koje mojem životu daju ljepotu, boje, smisao i snagu.

Andrea Šupih-Kvaternik

U Zagrebu, 2005.




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CONTENTS 1. CLASSIFICATION (20) ……………………………………………………………… 8 2. THE PROPERTIES OF AIR (3)………………............................................................. 29 3. THE WEATHER ( 6 ) …................................................................................. 31 4. MAGNETS ( 3).....................................................................................……………... 37 5. ATOMS, ELECTRONS AND ELECTRICITY (5)……………………………….............. 40 6. MATTER AND VOLUME (3) ……………………………….......................................... 45 7. MASS AND WEIGHT ( 5) ……………………………………………………............... 48 8. TESTING YOUR KNOWLEDGE(4) ……………………………………………............. 53 9. PHYSICAL AND CHEMICAL PROPERTIES OF SUBSTANCES (3) ....................... 57 10. ELEMENTS (3) .................................................................................................. 60 11.SUBSTANCES - Seprating solutions) (3) ............................................................ 63 12. SUBSTANCES Melting points and boiling points (4) .......................................... 72 13. GRAMMAR REVISION (4) ..................................................................................... 72 14. SOLVENT AND SOLUTE (2) ……………………………………………….......... 74 15. WATER - NEXT TO OXYGEN (6) …………………………………………................. 76 16. WATER-TREATMENT SYSTEM - ACTIVATED CARBON (1) ………………........ 82 17. HYDROLYSIS (2) ……………………………………………………………….............. 83 18. ACIDS (5) ……………………………………………………………….............. 85 19. FOLIC ACID (3) ……………………………………………………………….............. 88 20. TREATMENT OF THE LABORATORY SAMPLE (2) ………………………............... 91 21. LABORATORY SAFETY (2) …………………………………………………….............. 93 22. THE CELL - MILESTONES (3) ………………………………………………….............. 95 23. THE CELL (5) ………………………………………………………………………… 98 24. PROTOPLASM (4) ……………………………………………………………….............. 103 25. THE LIVING CELL ( 7) ……………………………………………………………......107 26. GENE SPLICING (5) …………………………………………………………..........113 27. A GENE IS CLONED (2) ……………………………………………………………......118 28. HELLO, DOLLY - CLONING AND ITS TEMPTATIONS (6) ……………………….....120 29. DOLLY - "A FARMYARD FREAK" (3) ……………………………………….........126 30. PROTEINS (5) ………………………………………………………………………….129 31. PROTEINS, ACIDS, FATS (3) …………………………………………………........134 32. PLASMIDS …………………………………………………………………………………...136 32. DISTRIBUTION OF NUTRIENTS IN PLANTS (6) ……………………………………...137 33. VEGETABLE OILS AND FATS (4) ………………………………………………...........143 34. FAT IN THE BODY ( 3) …………………………………………………………….............147 35. BACTERIA (4) ……………………………………………………………………................150 36. IRREGULAR FOREIGN PLURALS (1) …………………………………………..............154 37. MICROBES AS CHEMICAL MACHINES (2) …………………………………...............155 38. MICROBIOLOGY (4) ……………………………………………………………................157 39. OXYGEN, OXIDATION, ANTIOXIDANNTS (3)………………………………………......160 40. ENERGY FOR LIFE (4) .......................................................................................163 41. DIGESTION AND ABSORPTION (7) ……………………………………………….........167 42. DETERMINATION OF SUGARS (2) ………………………………………….................174 43. VITAMINS AND THEIR FUNCTIONS (3) …………………………………………..…... 176 44. VITAMINS (4) ……………………………………………………………………................179 45. ASCORBIC ACID (4) .................................................................................................183 46. SUPERNUTRITION (11) ……………………………………………………………...........187 47. NEW DISCOVERIES IN MINERAL NUTRITION (3) ………………………..................200 48. THE STORY OF MERCURY AND MAN (4) …………………………………................203




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CLASSIFICATION

A paragraph of classification divides people, places, or things into groups. Classification is used by nutritionists to describe different categories of food, by biologists to describe kinds of animals, and by psychologists to describe personality types. The words bellow signal a classification: categories classes groups kinds types Gathering thoughts on nutrition 1. Which foods do you think are particularly healthful? Make a list. 2. Which foods do you usually eat every day? Make a list. Five Essential Words The following words are important in this chapter. They are also common in many science readings and in everyday English, but often in a different context. energy, n. the power to act essential, adj. necessary, basic fuel, n. something burned to produce energy repair, v. to fix source, n. the beginning; the origin A. Choose the correct word from the Five Essential Words. Fill in the blanks. 1. For months my car did not work very well. It burned too much _______ . I was busy working and did not have the time or the_________ to fix it. Besides, I did not know the __________ of the problem. I finally took the car to a mechanic. He told me that the car was missing one________ part from its engine. He was able to __________ the car in less than an hour. 2. The human body uses food for __________ . Food also gives _______ to the body. It can also __________ minor damage in the body. Food is also a __________ of the vitamins in the body. Vitamins are __________ for our good health. Compare the two texts. B. Rapid reading and understanding




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Some words in a sentence are more important than others because they carry more information. Good readers focus on the important words when they read. Focusing on key words is faster and more efficient than reading every word in a sentence. The sentences below are from "The nutrients in Food". Practice reading and understanding these sentences rapidly. Underline the letter in front of the sentence which best conveys the meaning of the words in italics.

Examples: Corn oil is a vegetable fat. a. The oil from corn is a vegetable fat. b. Corn is a vegetable fat. c. Oil is a vegetable. People need complete proteins a. People must eat proteins which are every day. incomplete.

b. People must eat proteins which complete.

c. People must eat complete meals. 1. Their appetite is good. a. They want to eat. b. They want to sleep. c. They want to exercise. 2. All lean meats have iron. a. Some lean meats have iron. b. Meat without fat has iron. c. Clean meats have iron. 3. Vitamins help prevent diseases. a. Vitamins help prevent discomfort. b. Vitamins help prevent seasickness. c. Vitamins help prevent illnesses. 4. Vitamin D helps build strong a. People who get vitamin D are strong

bones. builders. b. People who get vitamin D do not have weak bones.

c. People who get vitamin D have long bones. 5. Carbohydrates provide heat a. Carbohydrates are hot.

and energy. b. Carbohydrates are fuel. c. Carbohydrates are active. 6. People need all the essential a. People need every necessary nutrient

nutrients. b. People need most of the necessary nutrients. c. People need a few of the necessary nutrients.

7. Vitamin A comes from fruits a. Lettuce has vitamin A.




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and vegetables. b. Hamburger has vitamin A. c. Bread has vitamin A. 8. Extra protein in the body a. All the protein is store. is stored as fat. b. Excess protein is stored. c. Expensive protein is stored. 9. The average adult has 10 to a. Everybody has 10 to 11 kilograms of

11 kilograms of body fat. fat. b. Children have 10 to 11 kilograms of fat.

c. A typical man or woman has 10 to 11. 10. People need about 800 a. Eat 800 grams of calcium every day. milligrams of calcium a day. b. Eat 600 milligrams of calcium every

day. c. Eat 800 milligrams of calcium every

day. Reading Skills: Identifying Topic Sentences Most paragraphs have one sentence which expresses the general idea or topic of the paragraph. This sentence is called the topic sentence of the paragraph. In most paragraphs in textbooks, the topic sentence is the first sentence. In other paragraphs, the topic sentence may be either the second or the last sentence. Identifying the topic sentence of a paragraph will help you understand the general idea of the paragraph quickly. Exercise 1. Directions: Choose the correct topic sentence for each paragraph below. Write the topic sentence of the paragraph on the line provided. Example: a. Water is found all over the world. b. Water has important nutrients. c. Water is essential for good health. __________________________________________________ It is necessary for every process of the body like digestion and absorption of food. In addition, water helps control the temperature of the body. It keeps the temperature at 37oC (98.6oF). Water also cleans the tissues. Water is found in all foods. For instance, fresh vegetables are 90 percent water, eggs are 74 percent water, and hamburger is 60 percent water. The topic sentence of the sample paragraph is c. Water is essential for good health. Finish the exercise.




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Paragraph 1 a. There are many ways to cook meat and grains. b. There are two kinds of proteins: complete and incomplete proteins. c. There are two kinds of amino acids. __________________________________________________ Complete proteins, which the body needs for growth, have all the essential amino acids. Meat, fish, poultry, eggs, milk, and cheese have complete proteins. The body needs complete proteins every day. The second kind, incomplete proteins, do not have all the essential amino acids. The proteins in vegetables and grains, for instance, are incomplete proteins. Two ways to form complete proteins from incomplete proteins are: (1) to mix vegetables and grains correctly, or (2) to add a small amount of meat or milk to a large amount of grains. The body can then use the complete proteins which result from the mixtures. Paragraph 2 a. If there is not enough iron in the diet, a person will get a disease that is commonly called anaemia. b. If people eat healthy meals, they will get all of the minerals they need. c. If people do not get enough oxygen, they will feel tired. Iron is the mineral that makes blood look red. _______________________________________________ . Anaemia is found all over the world. People with anaemia do not have enough iron in their blood. Because iron carries oxygen people who do not have enough iron do not get enough oxygen for their normal activities. Their heart beats faster so their bodies can get more oxygen. People who have anaemia often get tired easily. Sometimes their skin looks white; it does not look pink and healthy. Paragraph 3 a. When a grain is processed, it tastes better. b. When a grain is processed, it is more expensive. c. When a grain is processed, it loses vitamins. __________________________________________________ . For example, there is a big difference between brown and white rice. When rice is processed, the brown outside (husk) is lost. The brown outside (husk) of rice has an important B vitamin which white rice lacks. In short, brown rice has more B vitamins than processed rice. Paragraph 4




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a. Vitamin D is called "sunshine" vitamin. b. Vitamin D is found in only a few foods. c. Vitamins are essential in tropical countries. _____________________________________________________________ When people sit outside, ultraviolet rays from the sun change a fat in their skin to vitamin D. Vitamin D helps the body absorb calcium. It helps build strong bones, and it prevents a disease in children that is called rickets. When children have this disease, their bones bend because they do not become hard. Rickets is seldom found in sunny, tropical countries. Rickets is more common in countries that have long winters with little sunshine, in cities where pollution obscures the sun, or in towns surrounded by mountains which keep the sun out. Exercise 2 Directions: These questions are based on the completed paragraphs in Exercise 1. 1. Choose the best answer for each blank. 1. The topic of the sample paragraph is __________________ . a. water b. body temperature c. nutrients 2. The topic of Paragraph 1 is __________________ . a. complete and incomplete proteins b. a definition of amino acids c. a description of how to cook grains 3. The topic of Paragraph 2 is __________________ . a. oxygen b. minerals c. anemia 4. The topic of Paragraph 3 is __________________ . a. processed grains b. the importance of B vitamins c. color of vitamins 5. The topic of Paragraph 4 is __________________ . a. children b. climate c. vitamin D Reading Anticipation - Organization




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1. Number the paragraphs in "The Nutrients in Food". How many paragraphs are there? __________________ 2. Read the introduction (Paragraph 1). First nutrients are defined. Then the five general groups of nutrients are listed. In what order do you think the author discusses these nutrients? First: ____________________ Second: ____________________ Third: ____________________ Fourth: ____________________ Fifth: ____________________ 3. Quickly read only the first sentence of each paragraph. From these sentences, guess which paragraphs are about each of the topics listed below. Underline or circle the number/s which paragraphs are about each general topic. Paragraph 1 is an introduction. Finish the exercise. Topics Introduction Carbohydrates 1 2 3 4 5 6 7 8 9 10 11 12 13 Fats 1 2 3 4 5 6 7 8 9 10 11 12 13 Proteins 1 2 3 4 5 6 7 8 9 10 11 12 13 Minerals 1 2 3 4 5 6 7 8 9 10 11 12 13 Vitamins 1 2 3 4 5 6 7 8 9 10 11 12 13 Conclusion 1 2 3 4 5 6 7 8 9 10 11 12 13 4. Look at your list of topics above, and try and say in which paragraph you will probably find the answers to the following questions. __ a. Why are carbohydrates important? __ b. What are the best sources of calcium and phosphorus? __ c. Why do people need protein? __ d. In general, why are nutrients important? __ e. Give two examples of foods that have incomplete proteins. __ f. What happens to a person who does not have enough iron? __ g. How many vitamins are there? __ h. How much body fat does the average adult have? __ i. Why are the B vitamins important? __ j. Where does vitamin C in the diet come from?




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Reading Hints 1. Remember specific facts. As you read, try to understand and remember one specific fact about each topic in the list of topics above. 2. Focus on key words in a sentence. Words: 1,150 Suggested reading time 7:30 minutes

THE NUTRIENTS IN FOOD

1. Nutrients are the parts of food that are important for life and health.

Nutrients are important for three reasons. First, some nutrients provide fuel for energy. Second, some nutrients build and repair body tissues. Third, some nutrients help control different processes of the body like the absorption of minerals and the clotting of blood. Scientists think there are 40 to 50 nutrients. These nutrients are divided into five general groups: carbohydrates, fats, proteins, minerals, and vitamins.

2. The first group of nutrients is carbohydrates. There are two kinds of carbohydrates: starches and sugars. Bread, potatoes, and rice are starches. They have many carbohydrates. Candy, soft drinks, jelly, and other foods with sugar also have carbohydrates. Carbohydrates are important because they provide the body with heat and energy. Sugar, for instance, is 100 percent energy. It has no other food value. Sugar does not build body tissues or control body processes. If there are too many carbohydrates in the body, they are stored as body fat. The body stores fuel as fat.

3. There are two types of fats: animal and vegetable. Butter, cream, and the fat in bacon are animal fats. Olive oil, corn oil, and peanut oil are vegetable fats. The body has fat under the skin and around some of the organs inside. The average adult has 10 to 11 kilograms (20 to 25 pounds) of body fat. If adults eat too many carbohydrates and fats, they can add another 45 kilograms (100 pounds) to their bodies. Fat is extra fuel. When the body needs energy, it changes the fat into carbohydrates. The carbohydrates are used as energy. Fat also keeps the body warm.

4. The third group of nutrients is proteins. The word "protein" comes from a Greek word that means "of first importance". Proteins are of "first importance" because they are necessary for life. Proteins are made of amino acids, which build and repair body tissues. They are an important part of all the muscles, organs, skin, and hair. The body has 22 different amino acids. Nutritionists call eight of these amino acids essential because the body does not manufacture them.

5. There are two kinds of proteins: complete proteins and incomplete proteins. Complete proteins which the body needs for growth have all the essential amino acids. Meat, fish, poultry, eggs milk, and cheese contain complete proteins. The body needs complete proteins every day. Incomplete proteins do not have all the essential amino acids. The proteins in vegetables and grains, for instance, are incomplete proteins. Two ways to form complete proteins from incomplete proteins are: (1) to




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mix vegetables and grains correctly, or (2) to add a small amount of meat or milk to a large amount of grains. The body can then use the complete proteins which result from the mixtures.

6. Extra protein in the body can be changed to fat and stored as body fat. It can also be changed to carbohydrates and used for energy. If people do not eat enough carbohydrates and fats for the energy that they need, their body uses proteins for energy. Then the body does not have the proteins that it needs to build and repair tissues. A nutritious diet includes carbohydrates and fats for energy, and proteins for growth.

7. The fourth group of nutrients is minerals. There are more than twenty different minerals in the body. Three of the most important minerals are calcium, phosphorus, and iron. Calcium and phosphorus work together. The bones and the teeth contain 99 percent of the calcium in the body. If people have enough calcium and phosphorus, their bones and teeth will be strong and hard. In addition, their muscles, nerves, and heart will work correctly. Milk and hard cheeses are the best sources of calcium. After the age of 19, people need 400 to 500 milligrams of calcium a day. People who do not drink three glasses of milk daily can eat 50 hamburgers or 56 apples to get the calcium they need.

8. Iron is the mineral that makes blood look red. All lean meats have iron; liver is an especially good source of iron. Whole grains, nuts, some vegetables, and dried fruits also have iron. If there is not enough iron in their diets, people will get a disease that is commonly called anaemia. Anaemia is found all over the world. People with anaemia do not have enough iron in their blood. Because iron carries oxygen, people who do not have enough iron do not get enough oxygen for their normal activities. Their hearts beat faster so their bodies can get more oxygen. People who have anaemia often get tired easily. Sometimes their skin looks white; it does not look pink and healthy.

9. Nutritionists think there are thirteen vitamins that humans need. Vitamins are important because they prevent diseases and help control body processes. Vitamin A is important for healthy skin and eyes. People who do not have enough vitamin A may have night blindness. Some automobile accidents happen in the evening because people who lack vitamin A do not see the road well after they look at the bright headlights of a car. Vitamin A in the diet comes from deep yellow fruits and vegetables, dark green leafy vegetables, and whole milk.

10. When people have enough B vitamins, their appetite is good and their nerves are calm. B vitamins in the diet come from some kinds of meat and vegetables, milk, cottage cheese, and whole grains. When a grain is processed, it loses vitamins. For example, there is a big difference between brown and white rice. When rice is processed the brown outside (husk) is lost. The brown outside of rice (husk) has an important B vitamin which white rice lacks. In short, brown rice has more B vitamins than processed rice.

11. Vitamin C keeps the cells of the body together. It helps skin tissue recover from cuts and burns. Vitamin C in the diet comes from tomatoes, citrus fruits like lemons and oranges, and some vegetables such as cabbage and green pepper.




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12. Vitamin D is called the "sunshine" vitamin. When people sit outside, ultraviolet rays from the sun change a fat in their skin to vitamin D. Vitamin D is also found in cod liver oil and the eggs yolks. It is sometimes added to milk. Vitamin D helps the body absorb calcium. It helps build strong bones, and it prevents a disease in children that is called rickets. When children have this disease, their bones bend because they do not become hard. Rickets is seldom found in sunny, tropical countries. It is more common in countries that have long winters with little sunshine, in cities that have pollution that obscures the sun, or in towns surrounded by mountains that keep the sun out.

13. There is no one food that is essential but there are nutrients that are necessary for good health. If people want to be healthy and active they need to get all the essential nutrients. A healthy body needs carbohydrates, fats, proteins, minerals, and vitamins.

"Thousands upon thousands of persons have studied disease. Almost no one has studied health ".

Adelle Davis, a popular American nutritionist

Exercise 3. Directions: "The Nutrients in Food" is a classification. The classification shows how nutrients are divided into different groups. Make a diagram of this classification in the space below. Exercise 4: Directions: The reading discusses different nutrients. There is generally the same kind of information for each nutrient. Draw a chart on nutrients and fill it with the information you have read. Do not write sentences. Write only the information. Exercise 5. Below are some new specific facts. First, decide which general topic the fact talks about. Then indicate which paragraph the new fact belongs with. If the fact does not belong in any paragraph, put a 0. Example: ____ Because the body does not store extra vitamin C, it is important to get some vitamin C every day. (11) ____ a. Nuts and dried beans and peas are incomplete proteins. ____ b. Bright light destroys vitamin A in the body: As a result, people




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who work in bright light use more vitamin A than other people. ____ c. Young people need 0.5 to 0.6 grams of calcium a day. ____ d. In an average diet, carbohydrates give about 35 percent of the body's energy. ____ e. Pure fats give more than twice as much energy as carbo-hydrates. ____ f. There are hundreds of different kinds of proteins. ____ g. People who live near the coast get iodine from the water they drink. ____ h. If people do not have enough vitamin C, they can get a disease that is called scurvy. ____ i. About one-half of a person's body weight is water. ____ j. People who drink a lot of water, coffee, beer, or other liquids may lose a lot of the B vitamins in their bodies. Exercise 6. Directions: Practice asking and answering questions about "The Nutrients in Food". Work with your colleague. Use your chart. Do not look at the reading. Example: Q: What are the best sources of carbohydrates? A: The best sources of carbohydrates are bread, potatoes, grains, and sugar. Q: A: Q: A: Q: A: Exercise 7. Directions: Read each sentence. Find the paragraph in "Nutrients in Food" which explains the situation. Give specific advice. Example: Ms. Crosby does not have beautiful hair. (Paragraph 4) Ms. Crosby probably does not have beautiful hair because she does not get enough protein. If she wants to have beautiful hair, she should eat more meat, fish, cheese, eggs, or milk. 1. Mr. Stills is very thin. 2. Miss Nash does not have good posture. She does not stand straight




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because the muscles in her back are not very strong. 3. Mrs. Young does not have healthy teeth even though every day she eats foods which have calcium. 4. Mr. Simon is often tired and out of breath. 5. Mr. Garfinkel does not see very well when he is driving at night. 6. Ms. Mitchell is usually very nervous. 7. When Mrs. King cuts herself, her skin does not heal quickly. 8. Mr. Pride has weak bones. Exercise 8. Directions: There are several definitions in "The Nutrients in Food". Underline and copy them. ADDITIONAL READING SKILL: SCANNING Remember: SCANNING is a reading skill used by good readers to find specific information quickly. People scan to find facts and to answer questions. Exercise 1. Directions: 1. Read the questions. 2. Decide what kind of information to look for (e.g. a number, a date, a person's name). Fill in the blank with the kind of information you need. 3. Then scan the paragraph to find the sentence with the answer. Read the sentence to be certain you have the correct answer. 4. Write the answer.

A. What percentage of an egg is water? _____________________________________________________________ Water is essential for good health. It is necessary for every process of the

body, such as digestion and the absorption of food. In addition, water helps control the temperature of the body. It keeps the temperature at 37oC (98.6o F). water also cleans the tissues. Water is found in all foods. For instance, fresh vegetables are 90 percent water, eggs are 74 percent water, and a hamburger is 60 percent water.




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B. When did scientists announce the formula of vitamin B12? ______________________________________________________________ One type of anaemia from a poor diet is pernicious anaemia. In this disease,

there are too few red blood cells in the body and these red blood cells are too large. Pernicious anaemia is now controlled by vitamin B12. In 1948 scientists in England and the United States discovered a red crystalline substance which they identified as vitamin B12. In 1955 they announced the chemical formula of vitamin B12. Except for protein, B12 is the largest, most complex molecule scientists know about. When a person has pernicious anaemia, the doctor can inject a fraction of a gram of B12 into the muscle. B12 restores the blood to normal. It makes the person comfortable because it eliminates the nervousness associated with pernicious anaemia. It also helps the body use the amino acids it needs for growth.

C. Where was research on raw egg whites done? ______________________________________________________________ Nutritional studies have shown that a large amount of raw egg white in the diet

is unhealthy. When the egg white is not cooked, one of its proteins combines with an essential B vitamin in the egg. Then the body cannot absorb this B vitamin. When researchers at the University of Georgia fed laboratory animals raw egg whites, the animals lost their hair, got anaemia, and became nervous. However, when the animals ate the egg that was cooked until the white was firm, all of these symptoms disappeared.

D. How much does Dr. Herbert estimate Americans spend each year on

unnecessary vitamins? Dr. Victor Herbert, professor of medicine at Columbia University, warns

people about taking too many vitamins. He estimates that Americans spend about $2 billion each year on unnecessary vitamins. There is evidence that taking too many vitamins causes problems. Too much B6 may damage the liver. Too much vitamin C may damage growing bones. Too much vitamin E may cause headaches and blurred vision. Dr. Herbert suggests that Americans can get enough vitamins from a nutritious diet without taking vitamin pills.

E. How long does a taste bud last? __________________________________




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We talk about four basic flavors: sweet, sour, salt, and bitter. Yet, we can

distinguish hundreds of subtle flavors. The flavor of a food comes from all of our senses: taste, touch, sight, smell, and sound. Our taste depends on the taste buds on the tongue. Taste buds last about seven days. They are constantly being rebuilt. Children have about 9,000 taste buds and generally prefer bland foods. The taste buds are at their most efficient at the age of 20.

As some people get older, their taste buds are able to distinguish fewer flavors. People who drink too much alcohol may also lose the ability to distinguish subtle flavors.

F. Who thinks corn and oats are only for animals? _______________________________________________ People may reject certain foods because of their religious and cultural habits.

Hindus do not eat beef. Americans do not eat dog meat or horse meat. In the Tiv tribe in Nigeria, the men eat pork but the women are not allowed to. In certain parts of Africa, fish is considered an unclean food. Some Europeans think that corn and oats are only for animals. The Jains (a Hindu sect) in India believe that grains and seeds have the essence of life. Therefore, they avoid them in their diet. Ugandans think milk carries a skin disease. In sum, each cultural group has different foods which it does not eat.




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PARAGRAPHS FOR PRACTICE This exercise gives you additional practice in reading, understanding, and taking notes on paragraphs of classification.

1. Read each paragraph. Then reread it and take notes in the space provided in the margin. Write only the words you need in order to remember the information in the paragraph. Unless necessary, do not write complete sentences.

2. Afterwards, use your notes to make the classifications. When writing the classifications use only your notes and do not look at the whole text. A. Meat is the part of animals that Notes: people eat. There are four kinds of meat: red meat, organ meat (offal), fish, and poultry. Red meat includes beef, pork, lamb, and goat. Organ meats (offal) are liver, heart, kidneys, brain, and tongue. There are three classes of fish: saltwater fish, freshwater fish, and shellfish such as lobster and clams. Poultry includes chicken, turkey, duck, and hen. Classification: B. There are three main ways that vitamins Notes: are lost from foods. First, some vitamins dissolve in water. When vegetables are cooked in water, the vitamins go into the water. If the water is thrown away, the vitamins are lost. In addition, heat, light and oxygen change some vitamins. If vegetables are cooked, the heat changes some of the vitamins. Then these vitamins are no longer healthful. For instance, broiling grapefruit destroys some of its vitamin C. Finally, people sometimes throw away the part of a plant which has the most vitamins. For example, when flour is processed, the wheat germ, which is very rich in vitamins, is lost.

Classification:




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C. Let us look at three categories of diseases Notes: which are related to food. First, people may get a disease because they lack a nutrient they need. For example, if they do not have enough iron, they will develop a form of anaemia. Secondly, people may get food poisoning. There are four major sources of food poisoning: harmful bacteria, parasites (like worms), harmful chemicals, and naturally poisonous plants such as some mushrooms. Finally, some people have food allergies. These people are very sensitive to certain foods. for instance, some people get sick when they eat eggs because they are allergic to them. Classification:

D. About 1.03 billion pounds of chemicals are Notes: added to food in the United States every year. There are four main types of additives which are used. Preservatives keep food fresh. They are often used in potato chips, breakfast cereals, and oils. Other additives, like calcium chloride and other calcium compounds, help food keep its texture. For instance, a calcium compound is added to some salt so it will always pour easily. A third group of additives helps liquids stay mixed. These chemicals are usually used in peanut butter, ice cream, and mayonnaise. Finally, food colorings are used to make food look better. They are found in candies, soft drinks, and fruits. Classification:




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E. There are two general kinds of milk Notes: available: whole milk and concentrated milk. Whole milk has all the nutrients of milk. It is usually 2 to 4 percent butterfat and 8.5 percent milk solids. The rest is water. When some or all of the water is removed from the milk, the product is called concentrated milk. There are three main types of concentrated milk: evaporated, dehydrated, and condensed. Evaporated milk, which is very thick, contains only 40 percent of its water. It usually comes in cans. Dehydrated milk has no water. It is a dry powder that usually comes in boxes. Condensed milk is evaporated and sweetened. It is about 42 percent sugar. People choose which kind of milk to buy depending on their needs. Classification: F. Activities can be divided into categories Notes: according to the number of calories they use up. One kind of activity is a sedentary activity. A person who is reading, writing, watching TV, or playing cards uses 80 to 100 calories an hour. Another kind of activity is a light activity. A person who is doing a light activity, such as cooking, dusting, or walking slowly, uses 110 to 160 calories an hour. A third kind of activity, moderate activity, uses 170 to 240 calories an hour. These are activities such as sweeping, gardening, or carpentry work. A fourth group, vigorous activities, uses 250 to 350 calories an hour. These are activities like walking fast, bowling, or golfing. Finally a person who is doing a strenuous activity uses 350 or more calories an hour. These are activities such as swimming, playing tennis, or dancing. Classification:




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APPLYING SKILLS

Use the passages below to apply the reading and vocabulary skills you have studied in this chapter. When you read these passages, make a diagram of the classification the author presents. Later use your diagram to explain one of the reading passages to a colleague.

DRUGS Drugs can be divided into three main groups: those that a person can buy without a prescription, those that a person needs a doctor's prescription for and those that are illegal. Two popular non prescription drugs are caffeine and alcohol. Caffeine is found in coffee, tea, chocolate, and cola drinks. It is a mental stimulant; it stimulates the central nervous system and makes people feel alert. Students, for example, often find they can study better if they have a cup of coffee. On the other hand, caffeine can also make people nervous and irritable. If people drink too much caffeine they may have trouble sleeping. Alcohol is a depressant; it depresses the central nervous system. When people drink they have less control over their actions. They cannot walk in a straight line and they cannot drive as well as when they do not have alcohol in their blood. People who drink a great deal sometimes fall into deep sleep. Later, they may wake up with a strong headache which is called a hangover. In addition to these non prescription drugs, there are two major categories of prescription drugs: stimulants and depressants. The depressants include barbiturates and morphine. Barbiturates are used as sleeping pills. Morphine is used as a pain killer. The most common stimulants were amphetamines. Doctors used to prescribe amphetamines as diet pills. However, they have found that amphetamines can have serious side effects. They can make a patient very nervous and, when the drug wears off, the patient may feel very depressed. Doctors still give amphetamines to people with narcolepsy, an illness that causes sudden, uncontrollable attacks of sleep. The largest class of illegal drugs is the hallucinogens, drugs that change the way a person thinks and cause hallucinations or visions. LSD and mescaline are both strong hallucinogens. For some people marijuana is a mild hallucinogen. Marijuana generally brings a pleasant feeling. However, when people smoke marijuana, they sometimes cannot concentrate very well on their activities, such as their work or driving. GLOSSARY:




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Additional reading

MALNUTRITION

Some people suffer from malnutrition. Their diets contain too great a quantity of some nutrients, or too few calories. Nutritionists have three major ways of deciding if a person is suffering from malnutrition: physical exams, laboratory tests and diet studies. In the physical exam the nutritionist looks for external signs of malnutrition. For one thing, the nutritionist looks at the patient's skin. Rough, dry skin, for example, may mean that the patient does not have enough vitamin A. In addition, the nutritionist looks at the patient's mouth. Cracks at the corner of the mouth, a purplish or bright red tongue and bleeding gums can all be signs of vitamin deficiencies. The nutritionist also notices the patient's hair. If a patient does not have enough protein, the hair may be thinner and duller than normal. In laboratory tests, nutritionists check the amounts of nutrients patients have in their bodies. There are two main types of laboratory tests: blood tests and urine tests. A blood test can show, for example, if a patient has anaemia from too little iron in his or her diet. A urine test shows how much vitamin is absorbed by the body and how much passes through the body because it is not needed. If the patient's body absorbs a great deal of the vitamins, the patient may have a vitamin deficiency. There are three main ways nutritionists do diet studies. First, the nutritionist may interview the patient and ask general questions about the patient's diet. The nutritionist might ask questions such as the following: What do you usually eat for breakfast? How much coffee do you drink in a day? How often do you eat a raw vegetable salad? Second, the nutritionist may ask the patient to recall everything she or he ate in the past 24 hours. This information represents the person's usual diet. Finally, patients are asked to keep their own list of what they eat. Later the nutritionist looks at the list to see if the patient ate too much or too little of any nutrient.

GLOSSARY:




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Additional Reading

COFFEE AND TEA The most popular hot beverages in the world are coffee and tea. There are many kinds of coffee beans and tea leaves, which are processed and served in a variety of ways. Coffee in different countries may have different amounts of caffeine and different flavors. For example, coffee from Puerto Rico has less caffeine than Brazilian or Columbian coffee. Sometimes coffee has little caffeine because the beans are processed to remove most of the caffeine. In Germany, France and New Orleans, Louisiana, chicory is added to the coffee to give it a special flavor. There are three major ways to prepare coffee. American coffee makers use a filter. The two most common types are the drip machine and the percolator. A percolator has a metal filter. A drip pot uses a paper filter and produces a purer pot of coffee. Italian coffee, espresso, is made in an espresso machine which uses steam pressure to produce a thick, powerful drink. Turkish coffee is made in a special metal pot with a long handle. The coffee is placed in the boiling water in the pot. It is heated until it rises. Then the pot is removed from the heat until the coffee goes down. This procedure is repeated three times. Tea is the world's most common drink. There is only one tea plant, but there are many different varieties of tea. These varieties can be divided into two main types: green and black. Green tea is picked and then processed immediately. Black tea is processed about 24 hours after it is picked. The varieties of tea are different mainly because they come from different places. Furthermore, each variety is grown in different soil, and its leaves are picked at different times. Most of the world's tea is grown in China, India, Sri Lanka (Ceylon), Japan, and Southeast Asia. Some countries have particular tea-drinking customs and habits. In Japan, tea is served during a formal tea ceremony. Englishmen frequently add milk to their tea. Iced tea is a popular summer drink in the United States. It was invented in St. Louis, Missouri, in 1904 during the World's Fair. Richard Blechynden, an Englishman, was trying to sell hot tea at the fair. Because the weather was very warm, the public did not want hot tea. Blenchynden added ice to the tea and found that he had invented a popular drink.

GLOSSARY:

Additional Reading




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SOME ADVICE ON FOOD SHOPPING The average family spends about one-sixth of its income on food. Because food is expensive, it is important to spend money wisely when you shop. A careful shopper can prepare nutritious and delicious meals inexpensively. Here are some hints to help you shop better. Buy only the food that you need. There are several ways to avoid buying extra food. First, make a shopping list before you go to the store. Then, when you are at the store, follow your list carefully. Furthermore, do not go shopping if you are hungry. When you are hungry, foods look really delicious and you want to buy more than you need. Finally, go shopping alone if you can. If you shop with young children, they often ask you to buy them unnecessary food like candy. When you have a selection, choose the least expensive brand of a product. There are three points to remember when you buy a can of tomatoes, for example. First, look at the advertisements in the newspaper to see if your supermarket is having a "special" on canned tomatoes. In addition, when you are in the store, you should check the price per pound of tomatoes. Sometimes you save money if you buy the larger size can; sometimes however, you do not. Third, remember that a grade A product or a more expensive product is not necessarily more healthful than grade B or a less expensive product. Grade A tomatoes may look better, but all canned tomatoes have the same nutrients. Shoppers seem to have special difficulties when they buy fresh fruit and vegetables. There are several things to consider when buying fresh foods. Because fresh foods spoil if they are not used, you have to buy the correct amount for the number of people you are serving. Remember that a pound of some vegetables serves more people than a pound of other vegetables. For instance, a pound of peas in their pod is only two to three servings, but a pound of string beans is enough for six servings. In addition, plan to use fresh foods that are in season because fresh foods are generally less expensive when they are in season. Finally, choose fruit and vegetables that have a bright, fresh color. A good color is often a sign that the food has a lot of vitamins. Careful shoppers try to get as many nutrients as they can for each dollar.




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THE PROPERTIES OF AIR

(1) The earth is surrounded by a layer of air. (2) This is between 150 and 200 km thick and is called the atmosphere. (3) Air is invisible and therefore it cannot be seen. (4) But it occupies space and has weight in the same way that visible substances do. (5) Air, then, takes up space and has weight. (6) The atmosphere, therefore, weighs down on the surface of the earth. (7) However, this weight cannot be felt pressing on us (8) Because air not only exerts a downward pressure, but it also exerts pressure upwards and sideways, and this pressure is balanced by the equal pressure which our blood exerts in all directions. (9) In short, air exerts pressure in every direction. GLOSSARY property, n. - svojstvo visible, adj. - vidljiv occupy, v. - zauzimati exert pressure (on), v. - vršiti pritisak na, pritiskivati layer, n. - sloj substance, n. - supstancija invisible, adj. - nevidljiv weigh down on, v. - pritiskati EXERCISES A. Study the following statements carefully and write down whether they are true or not true according to the information expressed above. a) A layer of air surrounds the earth. b) A layer of air is called an atmosphere. c) Air can be seen. d) Air is a visible substance. e) The atmosphere presses down on us. f) We can feel the weight of the atmosphere. g) Air only exerts pressure upwards and sideways. h) Air exerts an upward pressure. B. Rephrasing Rewrite the following sentences replacing the underlined word(s) with expressions from the text that have the same meaning: Example: The layer of air which surrounds the earth is between 150 and 200 km thick. The atmosphere is between 150 and 200 km thick. 1. Air weighs down on the surface of the earth.




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2. Air exerts pressure upwards, downwards and sideways. 3. Air cannot be seen but it occupies space in the same way as do substances which can be seen. 4. Air takes up space and has weight. 5. The fact that air occupies space is shown in... C. Relationship between statements. Place the following expressions in the sentences indicated. Replace and reorder the words in the sentences where needed. Example: since (3) Air is invisible and therefore it cannot be seen. Since air is invisible, it cannot be seen. 1. consequently (3) 2. however (4) 3. in short (6) 4. it follows that (7) 5. nevertheless (8) 6. then (9) D. 1. Draw a diagram based on the reading of the passage: a) ............. is ………….. b) ........................which c) 1. is ................ 2. ............... space 3. has ................... 4. ............... in all directions. 2. Use your completed diagram to write out as many sentences as you can: a) b) c) a) c) 3. Use all the information in your completed diagram to write down a definition of air in one sentence.




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THE WEATHER 1. What makes the wind blow? The pressure of the atmosphere varies all the time. Air increases in volume as the temperature rises, and so a cubic meter of cold air is heavier than the same volume of warm air. As warm air is lighter, it rises. It is displaced at lower levels by colder air which moves in. Wind is simply the movement of air between high and low pressure areas. The bigger the difference between the pressures, the stronger the wind is. Atmospheric pressure is measured with a barometer. 2. How are clouds formed? The moisture in the atmosphere is produced by evaporation of water and by the breathing of living things. As water vapor is lighter than air, it rises. It goes on rising until it condenses. Then it can be seen in the form of clouds. The process of condensation continues until the water becomes too heavy to stay in the air and it falls as rain. 3. How is snow formed? Currents of very cold air make the water vapor in clouds freeze. The clouds then consist of minute particles of ice. But these ice particles remain lighter than air until the temperature falls below a certain point. Then they combine, become heavier, and fall as snow. Snowflakes are crystals with a beautiful, patterned structure. 4. What is lightning? Lightning is a sudden discharge of electricity from cloud to cloud or from cloud to earth. The same sort of effect can be produced by connecting the positive and negative terminals of a storage battery. This creates a short circuit and a violent spark is discharged. Lightning from the sky is produced in the same way, usually between clouds with opposite electrical charges. GLOSSARY condense, v. - change from gas to liquid minute, adj. - very small patterned, adj. - arranged in a particular way discharge, v. - a movement of electricity create, v. - make, cause violent, adj. - sudden and powerful spark, n. - the electricity contained by a body or a battery




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EXERCISES A. WORD BUILDING Look at these verbs and nouns compress - compression propel - propulsion expand - expansion divide - division invent - invention add - addition transmit - transmission multiply - multiplication extend - extension condense - condensation connect - connection observe - observation move - motion inform - information convert - conversion evaporate - evaporation produce - production irrigate - irrigation revolve - revolution distil - distillation B. Now choose the words from the list to complete the sentences below: 1. Machines have made mass.......... possible in factories. 2. Clouds are formed by the .......... of water vapor in the atmosphere. 3. c = F-32 is the formula for the ..... of temperature. 5 9 4. Forward ......... can be produced by backward thrust. 5. ............. is the process of reducing the volume of a substance by outside forces. 6. Galileo's ............ of the planets made him certain that the earth revolved around the sun. 7. The motor car was one of the most important ............. of modern times. Note that the ending -ion often indicates the process of doing something. C. QUESTIONS AND ANSWERS a. Answer these questions: 1. Which is heavier, cold air or warm air? 2. When does air increase in volume? 3. How long does water vapor go on rising in the air? 4. What do clouds consist of? 5. What happens when the positive and negative terminals of a battery are connected?




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6 How is lightning produced? D. Make questions for these answers using the words in brackets. 1. It is the movement of air between high and low pressure areas. (What...?) 2. With a barometer. (How...?) 3. Water vapor is lighter than air. (Which is ...?) 4. Until the temperature falls below a certain point. (How long ...?) 5. They have beautiful, patterned structure. (What sort of....?) E. WORDS IN COMBINATION a. Now rewrite the sentences below in the same way. Use the correct negative prefix in each case. 1. It is not natural for animals to live in zoos. 1. 2. Tom was not able to complete his experiment as his instruments were not accurate and his calculations were not correct. 2. 3. Metals are not organic. 3. 4. The exact number of organisms in the world is not known and not calculable. 4. 5. Our information about the moon is still not complete. 5. 6. The color of that flower is not usual. 6. 7. The two parts of this circle are not equal. F. Look at this example: physics ---------- physical Now write down the adjectives of these words: mathematics ................... technology .................. arithmetic ................... botany .................. chemistry ................... electricity ................... biology ................... geology ................... G. Look at this example:




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radiate radiation Now form a noun from each of these verbs in the same way: irrigate................ generate .................. combine ................. calculate................ classify .................. populate ................. form ................ transform .................. relate ................. concentrate ................ H. Choose the words from the list you have written to complete these sentences. 1. The ................... of Tokyo is about 10 million. 2. A chemist studies the .................... of substances. 3. One of the most difficult problems is to find enough sources of energy for the .................... of electric power. I. THE PASSIVE a. Look at this example How is wind caused? Wind is caused by differences in pressure. Answer these questions in the same way and write down the answers: 1. How is snow formed? 1. 2. How are clouds formed? 2. 3. How is lightning caused? 3. 4. How is the moisture in atmosphere produced? 4. 5. How is sulphur dioxide in the atmosphere produced?




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J. ARTICLES Look at this table of general and particular statements and fill in any missing words: General statement Particular statement 1. Water boils at 100oC. .... water in ... kettle is boiling 2. Air pressure is measured .... pressure on a high mountain is with a barometer. lower that at ground level. 3.... temperature is measured .... temperature last Sunday was with a thermometer 18˚C. 4. Farmers depend on rain. .... last rain here fell yesterday. 5. Liquids are denser than gases. .... liquid in this bottle is water. 6. Oil contains sulphur. .... in the North sea contains little sulphur. 7. Diamond is a carbon compound. .... diamond in her ring is very big. 8. Insecticides are usually made ....insecticide used on that farm is in chemical factories. DDT. Explain your choice of articles. K. Choose the correct form of the passive voice. The first calculating machine .....................(build) in 1642, but since that date, many improvements ................................(make). Electro-magnetic computers ...................(produce) for the first time in America in 1889. They ..................... (use) generally ............... until electronic computers ............. (introduce) in the 1940s. Since then, more and more advanced computers ...................... (produce) for use in all fields. Explain your choice of various Tenses in the Passive. L. Put the following verbs from this list into the appropriate sentence using the appropriate verbal form: use grow compose find 1. Microscopes ..…....... to examine very small organisms. 2. Butterflies ....……...... all over Britain. 3. Maize .....……....….... in warm countries. 4. carbon dioxide .....….. of carbon and oxygen.




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M. Here are ten halved sentences. Choose the right ending from list B to match the beginning in the list A. A B 1. When a hovercraft moves, we can neither see it, nor touch it. 2. If you don't know the you will see further. meaning of a word 3. Many scientists work in industry as they are so fast. 4. If water is heated to 100oC you can look it up in a dictionary. 5. A baby rabbit is blind when it boils. 6. If you use a more powerful it boils and evaporates. telescope 7. Most airlines use jet planes as they are so hard. 8. water evaporates when it is born. 9. Diamonds are useful for cutting as there is more money to support their work. 10. As oxygen is usually a gas, it travels on a cushion of air.




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MAGNETS

(1) A magnet is a substance which attracts certain substances. (2) A substance which is attracted by a magnet can itself be made into

a magnet. (3) Generally speaking, there are three substances which are attracted by a magnet: iron, cobalt, and nickel. (4) Substances which are attracted by a magnet are known as magnetic substances, and those which are not are referred to as

non-magnetic substances. (5) Iron, cobalt, and nickel are magnetic substances. (6) They are attracted by magnets and they can themselves be magnetized. (7) Mixtures of metals, or alloys, which contain a magnetic substance generally also have magnetic properties. (8) Some alloys containing none of the above metals, however, are also magnetic. (9) Certain alloys containing manganese, aluminium and copper belong to this class. (10) They are magnetic, even though they contain no metal which is itself magnetic. (11) A magnet will attract a magnetic substance like iron. (12) Not all parts of a magnet, however, have equal attractive force. (13) If a bar magnet is placed in iron filings, most of the filings will stick to the ends of the magnet, and very few will adhere to the central part. (14) The force of attraction, or magnetic force, is concentrated near the ends of the magnet. (15) These areas are known as the poles. (16) A magnet sets in a definite direction when freely suspended. (17) If a bar magnet is suspended by a thread and allowed to move freely, it will come to rest with one pole pointing towards the south. (18) The pole pointing towards the north is called the north-seeking, or the north pole, and that which points towards the south the south- seeking, or the south pole. (19) If the north poles of two freely suspended magnets are brought into proximity, so that they are close together, the ends of the two magnets will swing away from each other. (20) If on the other hand the north pole of one magnet is brought close to the south pole of the other, the two ends will attract each other. (21) A north pole will attract a south pole and repel another north pole, and it will be attracted by a south pole and it will be repelled by another north pole. (22) Like poles repel one another and unlike poles attract one another.




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EXERCISES: A. Contextual reference 1. In sentence (8), the above metals refers to: a) iron, cobalt and nickel. b) alloys. 2. In sentence (9) this class refers to: a) The class of alloys which contain a magnetic substance. b) The class of alloys which contain no iron, cobalt or nickel but are magnetic. c) The class of alloys which contain manganese, aluminium, and copper. 3. In sentence (10) they refers to: a) Manganese, aluminium, and copper. b) Certain alloys containing manganese, aluminium and copper. 4. In sentence (15) these areas refers to: a) The force of attraction, or magnetic force. b) The ends of the magnet. 5. In sentence (19) they refers to: a) The north poles. b) The two magnets. B. Rephrasing Rewrite the following sentences replacing the words printed in italics with expressions from the text which have the same meaning: 1. A substance which is attracted by a magnet can itself be made into a magnet. 2. Substances which are not attracted by a magnet are referred to as non-magnetic substances. 3. Generally speaking, mixtures of metals which contain a magnetic substance have magnetic properties. 4. Alloys which contain iron, cobalt or nickel are generally magnetic. 5. If a bar magnet is placed in iron filings, most of the filings will stick to the ends of the magnet. 6. The force of attraction of a magnet is concentrated near the ends of the magnet.




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7. A magnet which is freely suspended sets in a definite direction. 8. If the north poles of two magnets are brought into proximity with each other, they will repel each other. 9. The pole pointing towards the north is called the north-seeking pole. 10. A north pole will be attracted by a south pole. C. Relationship between statements Place the following expressions in the sentences indicated. Replace and reorder the words in the sentences where necessary. a) may be defined as (1) b) furthermore (2) c) therefore (5) d) that is to say (6) e) but (7+8) f) although (7+8) g) for example (99 h) then (11) i) although (11+12) j) for example (13) k) thus (14) l) for example (17) m) however (20) n) then (21) o) then (21) Rephrasing: GLOSSARY alloy, n. - legura iron filings, n. - željezne strugotine suspended, adj. - obješen, koji lebdi come to rest, v. - umiriti se proximity, n. - blizina repel, v. - odbiti, odbijati like poles - isti polovi unlike poles - različiti polovi force of attraction, n. -privlačna sila




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ATOMS, ELECTRONS AND ELECTRICITY

(1)In order to talk about electricity, it is necessary first to talk about the atom.

The idea of the "atom" has a long history, one extending back to about 600 BC and the time of the ancient Greeks. They believed that all matter was made up of atoms. The word "atom", in fact, comes from the Greek word "atomos", which means "indivisible". It was not until 1897 that it was discovered that the atom is not indivisible but is composed of even smaller particles. Among these particles is one called the electron.

(2)Electrons orbit around the center or nucleus of the atom, much as the planets in the solar system orbit around the sun. Electrons closer to the nucleus are held more tightly than those in the outer orbits. It is the electrons in the outermost orbit of certain kinds of atoms that can be made to flow as electric current.

(3)Electrons flow easily through certain kinds of materials called "conductors". Many metals, such as silver, copper, gold, and aluminium, are good conductors. Good conductors are used in electric circuits to provide a path for the current.

(4)Other substances provide strong resistance to the flow of current along the desired path. Substances such as hard rubber, glass, wax, and certain kinds of plastic, are good insulators. Thus, the cord (cable) on an electric appliance consists of a piece of wire, generally copper, surrounded by a type of plastic or rubber, which is the insulator confining the current to its path.

(5)The pressure that makes electrons flow along wires is called "voltage". Voltage may be created by a generator at a power plant or by an electric battery. When you turn on the light or an electric appliance, electrons are drawn from a generator at a power plant. When you turn the light or appliance off, there will be electric pressure or voltage built up at the switch, but no current will flow. It is somewhat similar to the way a water system works.

(6)When you turn on a water faucet or a tap, water flows through the pipes, which is like electric current flowing through wires. When you turn off a faucet, water pressure remains but no water flows through the faucet. Similarly, when you turn off an electric appliance, voltage remains, but no current flows. In a water system, the whole operation depends on water pressure generated by a water pump. In an electric system, the generator (or battery) creates the pressure called voltage.

GLOSSARY:




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EXERCISES: A. Underline all the words that you do not understand in the passage. Check

them in your dictionaries. B. Multiple Choice: Circle the number of the item that best completes the

statement. 1. Electrons will flow easily through copper and silver because they are good

________________ (1) particles (2) conductors (3) regulators (4) insulators 2. Electrons are smaller particles of _______________ (1) circuits (2) currents (3) voltage (4) atoms 3. One function of an insulator is to confine an electric current to its_____ (1) voltage (2) orbit (3) path (4) generator 4. Similar to the way that planets orbit around the sun, electrons in an atom

orbit around the __________________ (1) nucleus (2) generator (3) flow (4) voltage. 5. A substance that offers strong resistance to the flow of electric current is

called ________________ (1) a battery (2) a conductor (3) an appliance (4) an insulator 6. Another term for electric pressure is _______________ (1) current (2) voltage (3) faucet (4) switch




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7. Rubber, glass, and wax are good (1) insulators (2) conductors (3) regulators (4) generators 8. At a power plant a generator is used to create voltage, which is the pressure

that makes ________________ flow along electric wires. (1) atoms (2) circuits (3) electrons (4) orbits C. True-False: Write + if the statement is true and 0 if it is false and then correct the false statements to make them true. ____ 1. With a light turned off no current will flow but there will be voltage at the switch. ____ 2. It was discovered in 1897 that the electron was made up of particles

called atoms. ____ 3. An electric cord (cable) consists of wire surrounded by an insulator. ____ 4. Electrons closer to the nucleus of an atom can easily be made

to flow as electric current. ____ 5. Plastic or rubber is often used as conductors. ____ 6. Voltage can be created by a battery. ____ 7. When a switch is turned on, voltage will prevent current from

flowing. ____ 8. The Greeks believed that all electricity was made of atoms and

electrons. ____ 9. Aluminium and gold can be used as conductors. D. Word study I. In the following list of words one does not belong. Draw a circle around it.

Explain why. 1. copper, gold, planet, aluminium 2. voltage, plastic, rubber, wood 3. nucleus, atom, electron, wax 4. circuit, conductor, particle, current 5. faucet, matter, substance, material 6. generator, pump, battery, voltage 7. pipe, pump, faucet, glass




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II. From column B select the equivalent of the italicized expression in column A and place the letter of your answer in the blank. In some cases more than one answer is possible.

Column A Column B ___ 1. in order to talk a. yet ___ 2. composed of even b. similar to smaller particles c. in most cases ___ 3. much as the planets d. about the same as ___ 4. metals such as silver, copper e. still ___ 5.Thus, the cord (cable) on f. as a means to an electric appliance g. usually ___ 6. generally, copper h. like surrounded by i. to ___ 7. it is somewhat similar j. slightly to the way k. consequently l. therefore E. Grammar Practice I. Adverbial Clauses: When and while are used to introduce adverbial clauses

which modify verbs or adverbs. How many adverbial clauses can you find in the reading? List the verb or adverb that they modify.

II. Adjective Clauses: These clauses always have subject/verb word order, and

modify nouns and pronouns. Adjective clauses are introduced by: that, which, who, or whom. Underline the adjective clauses in paragraphs 1, 2,

4, and 5. Give the noun or pronoun that they modify.




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III. Synonymous Sentences: Which sentence is closest in meaning to the model sentence? Place the letter of your answer in the blank.

____ 1. In order to talk about electricity, it is necessary first to talk about the atom. a. The order of all discussion should include electricity and atoms. b. Discussion of the atom should precede any discussion of electricity. c. First, we ought to include atoms and electricity in the discussion. ____ 2. It is the electrons in the outermost orbit of certain kinds of atoms that can be made to flow as electric current. a. Certain atoms flow as an electric current. b. The orbit of certain atoms has electrons flowing as electric current. c. Electrons orbiting furthest from the nucleus of certain atoms can be induced to move as an electric current. ____ 3. When you turn the light or appliance off, there will be electric pressure or voltage built up at the switch, but no current will flow.

a. With the switch turned off, electric current will be stationary and

voltage will increase at the switch. b. No current will flow if the voltage keeps building up after you turn off the lights or the appliance. c. Voltage and electric pressure keep the current from flowing while the switch is turned off. F. Dictation: Copy paragraph 6 as your colleague dictates it.




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MATTER AND VOLUME

(1) Matter is the name given to everything which has weight and occupies

space. (2) It may usually be detected by the senses of touch, sight or smell. (3) Matter may exist in three states: solid, liquid and gas. (4) All substances,

except those which decompose when heated, like wood, may be changed into a liquid substance, and one in the liquid state may be changed into a gaseous substance. (5) Changes can take place in the reverse order as well: gases may be changed into liquids and liquids into solids. (6) A solid substance such as ice may be changed into the liquid state, or liquefied, to become water, and this may be changed into gaseous state, or evaporated, to become steam. (7) Steam may also be converted into water and water into ice.

(8) All matter occupies space. (9) The space occupied by a quantity of matter is called its volume, and this is usually measured in units such as cubic meters or cubic centimetres. (10) Solids have a definite volume and shape, liquids have a definite volume but no shape; the latter take on the shape of the container in which they rest. (11) Gases have no definite volume and no shape. (12) The volume of a piece of a solid substance, or a body, of regular shape, like a cube, a sphere or a cylinder, may be calculated by using mathematical formulae.

(13) The volumes of irregular bodies cannot be calculated by the use of regular formulae. (14) They may be measured by means of devices like displacement vessels and measuring jars. EXERCISES: A. Write down whether the statements are true or not according to the information from the text: _____ a) Matter can usually be seen, smelt or touched. _____ b) Matter can be seen, smelt and touched. _____ c) All substances can be changed from one state into another. _____ d) A liquid can be changed either into a gas or into a solid. _____ e) Volume is measured in cubic meters or cubic centimetres. _____ f) Substances have a definite volume and shape. _____ g) Gases have no volume. _____ h) All bodies have a definite shape. _____ i) A cylinder is a regular body. _____ j) The volumes of all bodies can be calculated in the same way.




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B. Rewrite the following sentences replacing the underlined words with expressions from the text which have the same meaning. 1. A substance in the solid state may be changed into a liquid substance 2. Gases may be changed into liquids and liquids may be changed into solids. 3. A solid may be changed into the liquid state. 4. A liquid may be changed into a gas. 5. The volume of bodies of regular shape, like cubes, are calculated by using mathematical formulae. 6. The volumes of irregular bodies may be measured by means of measuring jars. 7. Water may be changed into the gaseous state to become steam. C. Number the sentences in the text. Place the following expressions in the sentences indicated. Replace and reorder the words in the sentences where necessary. a) can be defined as (1) b) thus (5) f) then (7)) c) also (6) g) then (9) d) thus (6) h) whereas (11) e) for example (7) i) however (14) D. Contextual reference 1. In sentence 2, IT refers to: a) weight b) space c) matter 2. In sentence 4, ONE refers to: a) a substance b) a substance in the solid state c) a liquid substance 3. In sentence 6, THIS refers to: a) a solid substance b) water c) ice 4. In sentence 9. THIS refers to: a) a quantity of matter b) its volume




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5. In sentence 10. THE LATTER refers to: a) solids b) liquids c) a definite volume 6. In sentence 14. THEY refers to: a) irregular bodies b) formulae c) the volumes of irregular bodies E. Read and translate the description of this experiment: The Measurement of the Volume of Irregular Solids. Water is poured into the displacement vessel until it overflows through the

pipe into the measuring jar. The level of the water surface in the measuring jar is

read, and then the solid is lowered into the vessel until it is completely covered

by the water. Water is displaced and flows down the pipe into the measuring jar, and the level of the water surface in the measuring jar is read again. The volume of water displaced is equal to the volume of the body.




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MASS AND WEIGHT

Weight is measure of the pull of gravity. Suppose an astronaut weighs 80 pounds. The gravitational attraction between the astronaut and the earth equals a force of 180 pounds. On the moon, his weight changes. He weighs only 30 pounds. The moon's gravitational pull, is only one sixth of that of the earth. On his way to the moon, the spaceman actually becomes weightless. The gravitational pull of both the earth and the moon are negligible in space. The astronaut's weight changes when he lands on the moon. But his mass remains the same on the moon as on the earth. Mass denotes the amount of matter a body contains. It is constant, or changeless. In fact, the mass of any object remains the same wherever it is located. Mass and weight are often considered to be the same. There is a reason for this confusion. A gram used to be a basic unit of measurement for both mass and weight. At sea level. one gram of mass weighs one gram. The weight of two grams of mass is two grams. The greater the mass the greater the weight.

INERTIA Mass is closely related to another property of matter. This property is inertia. Inertia is the tendency of a body at rest to remain at rest, and of a body in motion to remain in motion. A body at rest remains at rest unless an outside force acts upon it. A body containing a great deal of mass strongly resists a change in its motion or in its rest. The greater the mass, the greater is the inertia of a body.

GENERAL PROPERTIES There are other properties common to all matter in varying degrees. Among them are elasticity, a granular structure, and the electrical nature of fundamental particles. The fundamental particles of an atom are the electron, proton and neutron. The proton has a positive charge. The neutron has neither a positive nor a negative charge. Current electricity is a flow of free electrons - electrons which are apart from the atom. All matter is elastic to some degree. Elasticity is the tendency of a body to return to its original shape after it is distorted by pressure or force. Salt and sand are granular. Matter is granular when it is composed of tiny particles. These tiny particles are the atoms and molecules that make up the various substances of the earth. You can also observe many special properties of matter. These special properties are not common to all bodies. They are apparent only in specific kinds of matter. Glass, for example, can be transparent or translucent. Wood is opaque. Matter can be hard, soft, brittle, malleable or porous.




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CLASSIFYING MATTER

All bits of matter, as we have seen, have common properties. But specific properties distinguish one matter from another. The scientists have grouped matter into elements and compounds. In their classification they use the broader term substance. They also recognize subgroups known as solutions and mixtures.

SUBSTANCES By definition, a substance is any particular kind of matter that has its own specific properties. An ounce of a substance has the same basic properties as a pound of the same substance. Water is a familiar substance. It is made of two kinds of atoms (hydrogen and oxygen), but each drop of water is like another drop of water. Special properties of matter: hard A hard material is difficult to scratch. (e.g. glass) soft A soft material is easy to scratch. ( e.g. chalk) brittle A brittle material breaks easily (e.g. glass) malleable A malleable material can be pressed into new shapes. (copper) flexible A flexible material bends easily (e.g. rubber) rigid A rigid material does not bend easily (e. g. concrete) porous A porous material is full of pores. (e.g. sandy soil) GLOSSARY - MASS AND WEIGHT mass, n. - masa weight, n. - težina pull of gravity - sila teža gravitational attraction (pull)-sila teža weightless, adj. - bestežinski negligible, adj. - zanemariv denote, v. - označavati basic unit - osnovna jedinica measurement, n. - mjerenje inertia, n. - inercija related to ,v. - povezan (sa) at rest - u stanju mirovanja in motion - u pokretu elasticity, n. - elastičnost particle, n. - čestica granule, n. - zrnce, granula charge, n. - naboj to some extent - u nekoj mjeri distort, v. - izobličiti




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apparent, adj. - očit compound, n. - spoj transparent, adj. - proziran translucent, adj. - propusan samo za svjetlo; pjeskaren opaque, adj. - neproziran hard, adj. - tvrd soft, adj. - mekan brittle, adj. - krhak, loman malleable, adj. - kovak porous, adj. - porozan mixture, n. - mješavina, smjesa scratch ,v. - (o)grepsti flexible, adj. - savitljiv, elastičan bend, bent, bent, irr. v. - svinuti, zavinuti rigid, adj. - krut smooth, adj. - gladak rough, adj. - hrapav, neravan, grub soluble, adj. - topljiv insoluble, adj. - netopljiv combustible, adj. - upaljiv non-combustible, adj.- nezapaljiv friction, n. - trenje dissolve, v. - rastopiti ductile, adj. - rastezljiv conductive, adj. - provodljiv flammable, adj. - zapaljiv, upaljiv inflammable, adj. - nezapaljiv soil, n. - tlo, zemlja EXERCISES: A. Give the Croatian equivalent for the following properties: smooth - rough - soluble - insoluble - combustible - non-combustible - transparent - translucent - opaque - ductile - conductive - flammable - inflammable -




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B. Find the opposites of the following properties: elastic - transparent - combustible - smooth - soluble rigid - C. Complete the following sentences: 1. Inertia is a tendency......................... . 2. The mass of the body is as constant as ......................... . 3. Mass is closely related to ......................... . 4. Elasticity is the tendency of a body ......................... . 5. Matter is made of ...................... and ....................... . 6. Weight is a measure of ...................... . 7. .................... denotes the amount of ...................... a body contains. 8. It is changeless or ........................ . 9. ...................... is a basic unit of measurement for mass and weight. 10. The greater the ...................... the greater is the weight. 11. Mass is closely related to .......................... . 12. The greater the mass the greater is the .................... of the body. 13. The fundamental particles of an atom are the ......................, ..................... and ....................... . 14. A neutron has neither a positive nor a negative ......................... . 15. ................. is the tendency of a body to return to its original shape. D. Find proper meanings from list B for the words in list A: List A List B 1. moon a. not moving 2. gram b. a particle of an atom 3. at rest c. composed of tiny particles 4. neutrons d. a planet 5. granular e. unit of measurement 6. compound f. consisting of 2 or more E. Give definitions for: a) mass - b) weight - c) inertia -




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F. Translate into English: 1. Inercija je jedno od svojstava tvari. 2. Masa je usko povezana s inercijom. 3. Substancija je širok pojam. 4. Neka svojstva nisu zajednička svim tijelima.




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TESTING YOUR KNOWLEDGE

NAME: DATE:

MATTER

A. Read the text carefully and circle the correct answers: 1. There are three states of matter: solids, liquids and gases. Some substances occur naturally in all three states. Others occur in only one of them. Water is normally a liquid, but it can occur as a solid - ice, and as a gas - water vapour. A change in temperature is usually the reason for a change in the state of a substance. If we heat ice, for example, it will change into a liquid - water. The temperature needed for changing the substance in this way from a solid state into a liquid is called the melting point. When water is heated until it starts to boil, it becomes steam or water vapour. So, at its boiling point a liquid, water for example, turns into a gas, in this case, water vapour. If we want to turn a gas into a liquid, we need to change its temperature again. This time we lower the temperature so that the gas condenses and turns into a liquid. When we lower the temperature even further, the liquid turns into a solid, e.g. water freezes and we get ice. The freezing point is the temperature at which water turns into ice. EXERCISES A. 1. There are three states of matter: a) solids, liquids and ice b) solids, liquids and gases c) ice, water vapour and liquid 2. Water normally occurs as: a) a liquid b) a solid c) a gas 3. A substance turns from one state to another because: a) we heat it b) we lower the temperature c) we change the temperature 4. Freezing point is the temperature at which: a) water becomes ice




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b) water vapour turns into a liquid c) water turns into steam 5. The boiling point of water is the temperature at which: a) a liquid turns into a gas b) a substance changes its state c) water turns into steam 6. A thermometer is an instrument for measuring: a) heat b) cold c) temperature 7. We measure temperature in a) degrees Centigrade b) degrees Centigrade or Fahrenheit c) Fahrenheit 8. Translate the following words into Croatian: a) temporary b) permanent c) nutrient d) container B. Put the letter in front of the appropriate number of the words of the same meaning: __ 1. occur a. quantity __ 2. manufacture b. characteristic __ 3. amount c. happen __ 4. property d. link __ 5. bond e. produce C. Choose and circle the synonyms: a) decide suppose b) explain c) believe a) precise exact b) general c) partial




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a) a few several b) many c) few D. Translate the following instructions into Croatian: 1. Treat no chemicals lightly. 2. Use no open flame near flammable solvents. 3. Never work alone in the laboratory. 4. If you spill anything, clean it up immediately. E. Fill in the gaps with the following words: volume; gas; absorption; elasticity; element; 1. -------------- is the tendency of a body to return to its original shape. 2. -------------- is the measure of the amount of space that matter occupies. 3. Each -------- has its symbol. 4. ----------- is a process in which one substance is taken in by another substance. 5. Liquid in the form of vapour is called --------------- . I. Translate the text into Croatian




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TESTING YOUR KNOWLEDGE: Translate the following passage into Croatian. NAME: DATE:

MATTER

Matter has certain properties or characteristics. One familiar property of matter is its state. There are three states of the matter: solid, liquid, and gas. Among other properties of matter are volume, weight, mass and inertia. Water provides a good example of how matter exists in three states. Ice is solid water. Melt the ice and it becomes a liquid. Heat the liquid water to the boiling point, and it turns to steam. Steam is the gaseous state of water. Many other substances can also exist as a solid, liquid or gas.

VOLUME All matter occupies space. Volume is the measure of the amount of space that matter occupies. The scientist uses special graduated container to measure the volume in the metric system. A solid has a definite volume. There is no change in the volume of a solid block of wood, for example, so long as it remains in one piece. Put a wooden block on the floor, in a box or on a shelf. Bury it. Hold it beneath some water. Wherever you place it, its volume remains the same. To change its shape and volume you must cut it, burn it, or change it in some other way. Similarly, a specific volume of a liquid remains unchanged. One litre of milk, for example, is a specific volume. It makes no difference whether the milk is in a bottle, poured into a pan, or spilled upon the floor. The one litre volume remains the same. But there is a difference between the shapes of a solid and a liquid. Unlike a solid, a liquid always takes the shape of the container in which it is placed. A gas also takes the shape of the container in which it is placed. It too, has no definite shape. but the volume of a gas varies according to the size of its container. You can pour a litre of milk into a gallon jug, and you still have only one quart of milk. A gas, on the other hand, spreads out when it is transferred from a small tank into a large tank. the gas takes the volume of its container.




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PHYSICAL AND CHEMICAL PROPERTIES OF SUBSTANCES

The study of the properties of substances is an important part of chemistry, because their properties determine the use to which they are put. The physical properties are those properties of a substance that can be observed without changing the substance into another substance. The chemical properties relate to its participation in chemical reactions, i.e. chemical changes. Matter may be classified according to its physical state, i.e. the stage of aggregation of the atoms, ions or molecules involved. For most purposes three major subdivisions are adequate: the solid, the liquid and the gaseous state. Sometimes more restricted categories such as the crystalline state and the plasma state are also used. In everyday life we are familiar with sodium chloride (NaCl) as a solid, mercury (Hg) as a liquid, and oxygen (O2) as a gas. We are also familiar with water as a solid (ice), as a liquid, and as a gas (steam) and with the transformation of water from one state into another. One might ask why some substances are solids, others liquids and still others gases at normal temperature and pressure. In addition one might ask what happens when a substance undergoes a change of physical state. The answer to these questions requires that we understand how these three states differ at the atomic and molecular level, how the specific chemical nature of each substance is related to the state or states of aggregation of its atoms, ions or molecules. The state or states of matter which are stable, i.e. show no tendency to transform spontaneously into another state, depend on the temperature of the substance and the pressure that is applied to it. The physical properties of matter in a given state also vary with temperature and pressure. Each pure substance may be recognized by specific physical properties, e.g. melting point, boiling point, freezing point, condensing point, density, solubility, conductivity, and many other properties which are characteristic of it. Most of these properties can be measured precisely and expressed in numbers. The chemical properties of a substance describe its ability to form new substances under given conditions. A change from one substance to another is called a chemical change or a chemical reaction. Most substances have the power to enter into many chemical reactions. That is why the chemical properties of a substance may be considered to be a listing of all the chemical reactions of a substance and the conditions under which they occur. The study of these reactions constitutes a large part of the study of chemistry.




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Main branches of chemistry: General chemistry is a survey of all the branches of chemistry. Organic chemistry is concerned with carbon and its compounds. Inorganic chemistry is concerned with the chemistry of elements other

than carbon and their compounds. Analytical chemistry is concerned with the identification, separation and quantitative determination of the composition of different substances. Physical chemistry is primarily concerned with the structure of matter and the laws, principles and theories which explain the transformation of one form of matter into another. Biochemistry is the chemistry of living organisms. GLOSSARY- PHYSICAL AND CHEMICAL PROPERTIES OF SUBSTANCES determine, v. - odrediti, određivati put to use - upotrijebiti, iskoristiti relate, v. - biti povezan, odnositi se na, prema participation, n. - sudjelovanje state of aggregation - agregatno stanje purpose, n. - svrha, namijena, upotreba solid, n./adj. - krutina, kruto, čvrsto stanje liquid, n./adj. - tekućina, tekuće stanje gas, n. - plin, plinovito stanje gaseous, adj. - plinovit steam, n. - vodena para pressure, n. - pritisak undergo, underwent, undergone, irr. v. - prolaziti kroz, podvrgnuti se require, v. - zahtijevati, tražiti stable, adj. - stabilan, stalan, postojan tendency, n. - sklonost, tendencija specific, adj. - specifičan melting point - talište boiling point - vrelište freezing point - ledište density, n. - gustoća solubility, n. - topljivost conductivity, n. - provodljivost




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listing, n. - nabrajanje occur, v. - javljati se, pojaviti se, događati se constitute, v. - ustanoviti, činiti EXERCISES A. Give definitions of the following. You may consult your dictionaries. - melting point - - boiling point - - freezing point - - condensing point - - density - - solubility - - conductivity - B. Give the definition of physical and chemical properties of substances. Find them in the passage. Physical properties - Chemical properties - C. Underline all the passive forms in the text. Copy three of them in the space below. D. Underline all the modal verbs. List them in the space below. E. Give an example for each of the following: - a physical change - - a chemical change -




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ELEMENTS

An element is a pure substance that cannot be broken down into other substance by ordinary chemical means. A "pure substance" consists of only one kind of matter. This pure substance, or element, is neither combined nor mixed with anything else. Gold, for example, is an element. If you take a piece of gold and break it into bits, the smallest piece will still be gold, assuming that you applied ordinary physical or chemical means such as heating, grinding, melting, etc. Whatever your method, nothing changed the basic substance. The tiniest piece of pure gold is an atom. We can also say that a chemical element is a substance that contains only one kind of atom. There are 103 elements recognized today, 92 of which are naturally occurring elements. Others are produced artificially only in atomic energy laboratories. Since 1964 scientists have been claiming to have created six new elements, but those elements have not yet been accepted officially. Of the known elements more than eighty are solids in their natural state. Two are liquids and ten are gases. Gold, silver, iron, copper, uranium, tin and aluminium are representative solids. Mercury and bromine are the two liquids. Hydrogen, oxygen and neon are examples of gases. Each element has a symbol consisting of one or two letters. Chemists use the symbol as an abbreviation for the element. In some cases, the symbol is the first letter of the element's name. For example, C is the symbol for carbon. If the names of two or more elements begin with the same letter, two letters of a name are used. Calcium has the symbol Ca. Some symbols come from an old word for the element. The symbol for lead, Pb, comes from the Latin word for lead, plumbum. A capital letter is used always as the first letter in a symbol of a chemical element. Chemists use the symbols of elements to write formulae for compounds. The formulae tell which elements and how many atoms of each are in a compound. The symbols also provide an international language for chemists. The symbols for all the elements are in the Periodic Table of Elements. EXERCISES A. Make a list of all the definitions found in the text. - - - - - - B. Fill in the table below. Give the name and the Croatian equivalent for the following symbols of elements.




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Symbol Name Croatian equivalent C Cu F Au H I Fe Pb Mg Mn Hg N O K Ag Na S Sn W Xe Zn Note: Be sure you have checked the English pronunciation of all the elements.




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DESCRIPTION OF AN ELEMENT

HYDROGEN 1. State of aggregation: gas 2. Color, odor: colorless, odorless 3. Molecular weight: 2.016 4. Density: 0.08988 g/dm3 at stpx = 1 atm/0oC 5. Melting point: -259.14oC 6. Boiling point: -257.7oC 7. Solubility in water: 21.5 ml/dm3 water at 1 atm 0oC 8. Occurrence: everywhere 9. Atomic number: 1 10. Valency: 1 (monovalent) 11. Atomic weight: 1.008 12. Reactivity: at room temperature net very reactive; reactivity increases in the presence of a catalyst. xstp = standard, temperature, pressure = standardne okolnosti EXERCISES: A. Here is some information on Mercury. List it as in the example on Hydrogen: .....silver grey, odorless .....mono- and divalent .....not very reactive .....liquid at room temperature .....13.600 g/dm3 .....not soluble .....630 K = -273.15oC .....no molecular weight .....80 .....usually as a sulphide; can be elemental .....200.6 .....234.3K = -273.15oC




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SUBSTANCES

Melting points and boiling points

Everyday substances are found in one of three possible "states of matter": solid, liquid or gas. For example, by changing the temperature, we can often change a solid into a liquid or a liquid into a gas. for example, between 0o and 100o C, water is liquid. However, if you cool water below 0o C, it turns to solid ice, and if you heat it above 100o C, it turns into gaseous steam. The melting point of water is 0o C and its boiling point is 100o C. You can turn natural gas (which is mostly methane) into a liquid providing it is cold enough. Liquid methane boils at a very low temperature indeed: - 161o C. It melts at an even lower temperature: - 182o C. So, at room temperature, it is much too hot for solid or liquid methane to exist. This is why it is a gas. In a similar way, you can get liquid steel if the steel is heated above its melting point of 1500o C. The melting point of a substance is the temperature at which the solid becomes a liquid; the boiling point is the temperature at which the pressure of escaping gas equals the atmospheric pressure. Mixtures are always impure. You can always tell a mixture from a pure substance, because a mixture rarely melts or boils at a sharp temperature. Instead, the changes happen over a range of temperatures. In the table, there are seven mixtures and two pure substances: only water and alcohol are pure. All the others contain more than one type of substance, and melt over a range of temperatures. You can check the purity of a particular substance by measuring its melting and boiling points. Solutions and suspensions. There are two different sorts of mixtures. Some are all mixed into one state of matter, and are called solutions. Steel (solid) and petrol (liquid) and air (gas) are like this. But some are in more than one state, and these are called suspensions. For example: suspension contains number of states smoke dust+air two: solid and gas fog water+air two: liquid and gas Exercises A. After checking all the words you do not understand in your dictionaries translate the text.




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Control Text. Read the following text. Underline all the words you do not understand. Make a list and find the meaning in your dictionaries. Translate the text. SUBSTANCES - Melting points and boiling points. Everyday substances are found in one of three possible states of matter: solid, liquid or gas. For example, by changing the temperature, we can often change a solid into a liquid or a liquid into a gas. For example, between 0oC and 100oC, water is liquid. However, if you cool water below 0oC, it turns to solid ice, and if you heat it above 100oC, it turns into gaseous steam. The melting point of water is 0oC and its boiling point is 100oC. You can turn natural gas (which is mostly methane) into a liquid providing it is cold enough. Liquid methane boils at a very low temperature indeed -161oC. It melts at an even lower temperature: -182oC. So, at room temperature, it is much too hot for solid or liquid methane to exist. This is why it is a gas. In a similar way, you can get liquid steel if the steel is heated above its melting point of 1500oC. The melting point of a substance is the temperature at which the solid becomes a liquid. The boiling point is the temperature at which the pressure of escaping gas equals the atmospheric pressure. Mixtures are always impure. You can always tell a mixture from a pure substance, because a mixture rarely melts or boils at a sharp temperature. Instead, the changes happen over a range of temperatures. All mixtures contain more than one type of substance, and melt over a range of temperatures. You can check the purity of a particular substance by measuring its melting and boiling points. Solutions and suspensions. There are two different sorts of mixtures. Some are all mixed into one state of matter, and are called solutions. Steel (solid) and petrol (liquid) and air (gas) are like this. But some are in more than one state, and these are called suspensions. For example:

suspension contains number of states smoke dust+air two: solid and gas

fog water+air two: liquid and gas




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EXERCISES A. Number the paragraphs B. Paragraph 1. 1. Find a passive sentence and copy it. 2. Underline all the nouns and adjectives and make a list below: NOUNS ADJECTIVES 3. Underline all the modal and auxiliary verbs by a double line. Paragraph 2 1. Underline all the modal and auxiliary verbs. Make a list. MODAL AUXILIARY Paragraph 3 1. Find comparatives and copy them. 2. Make a list of all the adjectives in this paragraph. 3. Find all the pronouns and underline them.




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Paragraph 4 1. Underline all the nouns and adjectives and make a list. NOUNS ADJECTIVES 2. Find a Present Participle. And copy the sentence. Paragraph 5 1. What tense is used in this paragraph. Say why. 2. Make a list of the verbs used in this paragraph. Paragraph 6 1. Copy all the passive forms. B. 1. Find the definitions in the text and copy them in the space below. 2. Make a diagram of the classification of mixtures in the space below. C. Translate the text




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Control Text SUBSTANCES

Separating solutions Solutions are not stopped by filters. In a solution, one or more substances are dissolved by another substance. The one doing the dissolving is called the solvent and the ones being dissolved are called solutes. The mixture of a solute and a solvent is all in one state of matter, and so it will pass through a filter together as a single substance. This is, however, not true for a suspension, because a suspension is separated into the substances making it up. For example, a vacuum cleaner filters the dust from dusty air by passing the suspension through a paper bag. The paper traps the dust but allows the air to pas through. In the same way, filtration is used to separate a suspension of a solid in a liquid. Note that the solid gets trapped by the filter paper. Solids from solutions. In many cases, solutions contain solid solutes dissolved in a liquid solvent. Some common solvents are water, alcohol, acetone and petrol. To separate the dissolved solids from a solution, you need to use heat. The liquid solvent boils off, but the bp (boiling point) of a dissolved solid is too high for it to turn to gas. The gaseous solvent can be turned back to liquid by passing the gas through a tube surrounded by a cooling water-jacket. Sometimes, the heating is done in an open basin and the solvent is allowed to escape. Both methods are shown below. The first is called distillation, and the second evaporation. Evaporation is a process in which liquids are turned to gases by heating; condensation is a process in which gases are turned to liquids by cooling; distillation is the evaporation and condensation of the solvent from a solution. Liquids and gases from solutions. It is not easy to separate a liquid solute from a solution. Both solute and solvent evaporate together, producing a mixture of gases to be condensed. To separate this gaseous mixture a fractionating column is used. The whole process is called fractional distillation, as shown. The hot gases coming off the boiling liquid warm up the beads on the column. Until the temperature of the column reaches the bp of the liquid, the gas condenses on the beads. After a short while, the column gets hot enough for the liquid with the lower bp to reach the top of the column. But the one with the higher bp keeps condensing and running back to the vessel. So, the two liquids are separated because of the difference in their boiling points.




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EXERCISES A. 1. Check the meaning of the following words. Mark what part of speech they belong to ( n., adj., v., adv., etc,) substance - solute - dissolved - dissolving - solvent - solute - mixture - state of matter - suspension - separated - filter - dust - paper bag - trap - filtration - heat - boil off - turn back - tube - surrounded - water - jacket - basin - distillation - evaporation - condensation - fractionating column - come off - bead - bp - vessel - 2. How many of the nouns can be transformed into verbs, and how many verbs can be transformed into nouns? Give examples. Example: mixture - mix

escape ,v. - escape, n.




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3. How many phrasal verbs can you find in the text? Make a list. Example: cool off B. Number the paragraphs. C. Paragraph 1 1. Find a passive sentence and copy it in the space below. 2. Find two participle clauses. Copy them and then transform them into relative clauses. 3. Find a sentence in the Future Tense. Copy it in the space below. C. Paragraph 2 1. Underline all the adjectives. 2. Underline all the participles with a double line. D. Paragraph 3 1. Underline all the nouns. 2. Underline all the verbs with a double line. E. Find all the definitions in the text and copy them below. F. Make a diagram of the classification of substances.




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GLOSSARY substance, n. - tvar, supstanca, supstancija dissolve,v. - otapati acid, n. - kiselina measure, v. - mjeriti measure, n. - mjera density, n. - gusto}a differ,v. - razlikovati se condition, n. - stanje heating, n. - grijanje decompose, v. - raspadati se, razgraditi se semiconductor, n. - poluvodič posses, v. - posjedovati, imati property, n. - svojstvo cloud ,n. - oblak EXERCISES A. Make the following sentences interrogative and let your colleague answer them in interrogative form. Use: Do, What, How, ......... The substance dissolves in some acids. The instrument measures the medium density. These processes differ from chemical reactions. The substance actively enters into the reaction. The outer electrons leave the atom in some cases. These substances react in certain conditions. The temperature rises during this process. Heating ionizes gas. These molecules decompose in certain conditions. This procedure reduces energy losses. Semiconductors posses valuable properties. The temperature remains constant throughout the experiment. The substance catalyzes some chemical reactions. Each atom has an electron cloud in normal conditions.




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B. Make questions with the words in brackets: Use: What, Why, How, When, etc. You measure it. It enters the reaction. He develops it. They establish it. He looks into the problem. Their results vary. They sometimes obtain different results. They maintain the same temperature. It is subjected to research. I analyze the samples. We filter off the impurities. They often repeat the experiment. We often discuss the problem. They check the measuring instruments. They inspect and wash the test tubes.




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GRAMMAR REVISION TEST

A. Make the following sentences negative using the word in the bracket, to make it first interrogative. 1. The substance dissolves in some acids /Do, What/ 2. The instrument measures the medium density. 3. These processes differ from chemical reactions. 4. The substance actively enters into the reaction. 5. The outer electrons leave the atom in some cases. 6. These substances react in certain conditions. 7. The temperature rises during this process. 8. Heating ionizes gas. 9. These molecules decompose in certain conditions. 10. This procedure reduces energy losses. 11. Semiconductors posses valuable properties. 12. The temperature remains constant, throughout the experiment. 13. The substance catalyses some chemical reactions. 14. each atom has an electron cloud in normal conditions. B. Make questions with the words in brackets: 1. You measure it. /what, why, how, when/ 2. It enters the reaction. 3. The temperature remains constant. 4. He develops it. 5. They establish it. 6. He looks into the problem. 7. Their results vary.




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8. They sometimes obtain different results. 9. They maintain the same temperature. 10. It is subjected to research. 11. I analyse the samples. 12. We filter off the impurities. 13. They often repeat the experiment. 14. We often discuss the problems. 15. They check the measuring instruments. 16. They inspect and wash the test tubes.




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SOLVENT AND SOLUTE

A solution has two parts: the solvent and the solute. The solvent is the substance present in the greater quantity. In the case of a sugar solution, water is the solvent. The solute is the part present in the smaller amount. Sugar is the solute in a sugar solution. There is still another way to think about the solvent - solute relationship: the solute is the substance which is dissolved. The solvent is the substance in which the molecules of the solute are dispersed. Sugar dissolves in the formation of a sugar solution. The sugar molecules disperse within the water. Water is an important solvent. In fact, it is the most common solvent available to the chemist, the housewife, and the student of science. Water is highly reactive.

SOLUTIONS The most common solutions consist of a solid within a liquid. But solutions can also involve other states. For example, there are solutions of gases within liquids. Solutions have special properties that set them apart from other mixtures. A scientist defines a solution as a mixture composed entirely of individual molecules and atoms. Suppose you had mixed sugar with salt. You would have a mixture. But the individual particles would be grains of sugar and salt, not molecules. The tiny molecules take on a very specific quality in the definition of a solution. The molecules are distributed uniformly throughout the entire amount of the solution. The breakdown of a sugar lump into water is a physical change. A solution results, but there has been no chemical reaction. No new materials have been produced.

TRUE SOLUTIONS There is no visible proof of a sugar in a sugar solution. But there is a simple way to verify the presence of sugar. A sugar solution is a true solution. Scientists have established certain properties of a true solution. It never settles. That is, the parts of it never separate. It can stand indefinitely. Yet, you will never see a bottom layer or an upper layer beginning to form. There is simply no settling. Some solutions are colored, others are colorless. If not too highly colored, a true solution is clear. Shine a beam of light along one surface of the solution. Look through the solution from one side, and you will see the beam clearly. The freezing point of a true solution is lower than the freezing point of water. You can easily test this property with sugar solution. The freezing point of

water is O °C ( 32oF). Does sugar solution freeze at this temperature? GLOSSARY - SOLVENT AND SOLUTE




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solution, n. - otopina involve, v. - uključivati set apart, v. - izdvojiti grain, n. - zrno uniformly, adv. - podjednako, pravilno verify, v. - provjeriti establish, v. - ustanoviti, utvrditi, settle, v. - taložiti se disperse, v. - raspršivati se available, adj. - dostupan EXERCISES A. Find one word to denote the described: 1. One of three states of matter; it has a definite volume _________ 2. The ability of a substance to be dissolved; it varies with the temperature. _________ 3. A special kind of mixture having similar properties throughout. _________ 4. Any material, but usually a liquid, that can dissolve another substance. _________ 5. The change of matter into another substance as a result of a chemical reaction. _________ 6. Anything that takes space and has weight. _________ B. Complete these sentences following the pattern: A scientists defines it. It can be defined. 1. The sugar molecules disperse it. _______________ 2. We can look through it. _______________ 3. You can dissolve it. _______________ 4. A chemist can freeze it. _______________ 5. One can see a beam of light. _______________ 6. You cannot see a bottom layer. _______________ C. Find equivalents in column B for the words in column A. 1 entirely a. evenly 2. establish b. indefinitely 3. amount c. completely 4. forever d. quantity 5. equally e. define




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WATER - NEXT TO OXYGEN

Civilization has long centred around sources of water. Water is essential to man - he cannot live without it. Not only is it more important to him than food, but without it he cannot grow crops, run factories, wash himself and his clothes, or keep his home clean.

ADDITIONAL WATER FOR MAN'S NEEDS

One of the most serious problems facing us today is that of how to get more water for man to use. As we know, the world's population is literally exploding. It is expanding at such a rapid rate that scientists predict there will be more people than our planet can house or feed properly. It was accurately estimated in 1960 that by the year 2000, the population of the world would be double. Nearly three quarters of the earth's surface is covered by water - undrinkable water, as far as man is concerned. This water cannot be used by man because of its high mineral content. Of the remaining one quarter of the earth's surface, at least 60% is considered to be arid. In these dry areas water is indeed precious. Very few crops can be grown, and this means that few people can be supported there. There are different degrees of water purity. Purity is measured by the amount of impurities in the water. For instance, water is considered to be of high quality and potable if it has no more than 500 parts minerals, or salts, per one million parts of water. Sea water, on the other hand, contains about 35,000 parts per million (ppm). For purposes of irrigation, water can have from 1,000 to 3,000 ppm.

WATER FOR INDUSTRY AND AGRICULTURE Dual water supplies, though expensive, would help to use available water more efficiently. The purer water could be used only for drinking, and the less pure water for other purposes such as washing and agriculture. The reason man cannot live on sea water is that the human kidney cannot excrete salts in a concentration of more than about 2%. Sea water contains approximately 3.5% minerals. This means that for every 100 millilitres of sea water drunk, the kidneys would have to excrete a volume of 175 millilitres of fluid in order to dilute the salt concentration. The additional 75 millilitres of fluid would be drawn from the body's stores of water, in and around the cells. This, in effect, dehydrates the body. People who drink sea water soon become delirious. When this happens, they have become just as dehydrated as a man on a desert without any water at all.




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WHAT TO DO

A partial answer to the problem of water scarcity is conservation. One way to conserve water is to circulate water used for industrial purposes over and over. When water is iced for cooling the machinery in a large factory, it is ordinarily used only once, and then allowed to run into a common sewer with all the waste material from the factory. However, if recirculation of water is not considered when the plant is being built, it is often very expensive to install such a system at a later time. Another way to conserve water is to use treated and untreated sewage for irrigation of crops. One problem here is that the flow of sewer water comes all year round, regardless of how wet the ground may be already because of natural precipitation. Another way to solve the problem of water scarcity is to learn to make use of the most abundant supply of water we have - the sea. If we could learn to get potable water from sea water, we would be sure of never having a water shortage.

USE OF SEA WATER The processes by which sea water is made usable are of two general kinds. One involves taking the minerals out of the solution. Taking the minerals from the saline water is usually done by chemical methods. Extracting pure water from the solution can be done in a number of ways. One is by distillation, which involves heating the solution until the water evaporates, and then condensing the vapour. Extraction can also be made by partially freezing the salts in the remaining unfrozen solution. A gas such as propane will combine with water molecules in a saline solution to form a solid product, called a hydrate. When this solid is melted (heated) the result is the original propane and pure water. The main problem with all of these methods lies in the cost of processing. It is the cost of the energy needed to convert sea water to drinking water that is so high. In the United States, electricity, and fossil fuels, such as coal and oil, are the main sources of energy. But in underdeveloped countries where fossil fuels do not exist and electricity is an unavailable luxury, other sources must be sought.

SOURCES OF ENERGY The most likely sources of energy in arid regions are the wind and the sun. Wind energy has been used to a limited extent in many countries; machines to use it more effectively are still being developed. However, the amount of wind available varies with the location and the season of the year. Solar energy seems to offer more hope than any other source of energy, particularly since those areas most in need of water lie rather close to the equator and have a relatively clear atmosphere. But better ways of taking advantage of this inexpensive - even free - source of energy need to be found.




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Another interesting source of energy is the heat that can be recovered from radioactive waste material. This source is dependable and predictable, but more study and research is still needed in this area. In addition to the problem of finding an inexpensive form of energy for desalination of sea water, each process seems to present other problems. For instance, when the saline solution is frozen, the salt left in brine sticks to the ice crystals of water; this makes it necessary to clean the crystals before they are melted. And all distillation that takes place at above 80o - 90o C is hampered by the minerals that accumulate on the sides of the containers. This makes heating the solution more difficult and more expensive. It essentially insulates the container against further transfer of heat from the outside. But, all of the problems are solvable, given enough time, interested people and the funds necessary to carry out the research. EXERCISES A. Circle the correct ending for each sentence below: 1. Water covers about a. one half of the earth's surface. b. three-quarters of the earth's surface. c. three-eighths of the earth's surface. 2. Water is considered to be of high quality and potable if the mineral content is no more than a. 500 ppm. b. 3,000 ppm. c. 35,000 ppm. 3. The main problem of all present methods of extracting usable water from sea water lies in a. the lack of equipment. b. the cost of processing. c. the shortage of labor. 4. Man cannot drink sea water because a. the oxygen content is too low. b. it contains harmful bacteria. c. the mineral concentration is too high. 5. Distillation involves heating the solution a. and then freezing it. b. and then condensing the vapor. c. and then applying chemicals to it. 6. A gas such as propane will combine with water molecules in a saline solution to form a. a hydrate. b. protium. c. a nodule.




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7. The most likely sources of energy in arid regions are a. coal and oil. b. the wind and the sun. c. radioactive waste materials. B. Three of the four words on each line are similar in meaning or have something in common. Draw a line under the word that does not fit. 1. dual, potential, two, twice 2. delirious, dry, dehydrated, arid 3. accumulate, collect, gather, invert 4. sewer, pipe, brine, drain 5. seedling, shocking, surprising, startling 6. absolutely, literally, approximately, really 7. rainfall, maturity, precipitation, hail 8. place, insulate, put, install 9. advice, warning, hybrid, admonition 10. distillation, extraction, prediction, desalination C. Before each word in list A write the letter or phrase from list B that means the same. List A List B literally a. having two parts 2. arid b. drinkable 3. potable c. dry 4. dual d. really 5. dehydrate e. place in position for use 6. install f. remove water (from) 7. precipitation g. a salt solution 8. propane h. gather, collect 9. desalination i. rain, snow, etc.

10. accumulate j. removal of the salt content 11. brine k. C3H8




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D. Each sentence below contains two words joined by a hyphen ( - ). Write a new sentence that shows how the words joined together describe the word that follows them. The first two have been done for you. 1. Many disease-causing microbes, in fact, are found in perfectly healthy hosts. 1. Many microbes that cause disease, in fact, are found in perfectly healthy hosts. 2. A ruminant is a plant-eating animal whose stomach consists of several parts. 2. A ruminant is an animal which eats plant(s) whose stomach consists of several parts. 3. Large computers and data-processing systems have made the demand for mathematicians greater and greater. 3. 4. It is not just an accident that some are solid-colored tulips while others are streaked. 4. 5. Growth-regulating chemicals are applied in minute amounts to control the growth and behaviour of crop plants. 5. 6. A great deal of crop loss occurs each year as a result of low- temperature injury. 6. 7. An artificial satellite is a man-made object intended to orbit the earth, the moon, or another planet. 7. 8. Phytoplankton are tiny one-cell plants that drift at the mercy of the currents. 8. 9. The production of light and electricity by marine animals, the formation of sound-scattering layers, and the damaging effects of certain organisms come within the province of the marine biologist also. 9. 10. If the laws of motion are applied to rolling balls, to falling bodies, to horse- drawn wagons, and to ships sailing the seas, could they also apply to the moon going around the earth and to the planets going around the sun? 10.




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TEST

A. Complete the following passage using the given words: solvent, complex, occur, nutrient, blood, aqueous solution, suspension, wide range of, reactions, essential, structure, tissues, achieve, hydrolysis reaction. Water is the ................. in which the .................. reactions of living processes ............... . The movement of ........................ through the body is .................by means of .................. which is an ................... ...................... and ............... . Water is also important in a ........................ of other functions: for instance it takes part in .................. .................. , is an ........................ part of the structure of many plant and animal ...................... .

B. Match the following words with their descriptions and write the letter in front of the number. ..... 1. Enzyme ..... 2. Alloy ..... 3. Solutions ..... 4. Absorption ..... 5. Cellulose ..... 6. Ecology ..... 7. Fat ..... 8. Cell ..... 9 pH a) a special kind of mixture having similar properties throughout. b) The study of all relationships of living things to their surroundings, and to each others. c) The smallest whole part of a living thing. d) A process in which one substance is taken in and held by another substance. e) A substance consisting of a mixture of 2 or more metals or of a metal and non-metal. f) An organic catalyst. It promotes chemical reactions in body cells. g) A carbon compound which supplies energy to the body. h) The most common complex sugar; forms the wall of plant cells. i) Negative decimal logarithm of hydrogen-ion concentration, giving measure of acidity or alkalinity of a solution.




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WATER-TREATMENT SYSTEM - ACTIVATED CARBON

This system is effective at removing chloroform, chlorine, some pesticides, organic chemicals and bad taste and odor. The contaminants cling to the porous surface of the carbon, which is usually contained in a replaceable filter. But carbon or charcoal filters have one serious drawback: they require vigilant maintenance. Specialists warn that the organic material that collects on the carbon surface can supply a food source for bacteria that may produce endo-toxins. These poisonous substances, thought to be carcinogenic, may eventually end up in your "clean" water. Researchers found that the under-the-sink models containing powdered activated carbon only removed chloroform in the first three gallons of water. Afterwards, the water coming out of the filter contained more chloroform than the water going in. Most experts agree that frequent changing is essential.

DISTILLATION Water is heated until turns to steam and then the steam is condensed into water. Theoretically, this removes all bacteria and contaminants from water. But theory is not practice. distillation systems do not necessarily remove chloroform and other organic chemicals, which can vaporize with the water and then recondense. It was found that using an activated-charcoal filter with a distiller will increase its organic-removal rate to over 90 percent. You may need pre-treatment if your water is extremely hard or full of iron, which fouls the device. GLOSSARY cling, clung, clung, irr. v. - uhvatiti se, prilijepiti se charcoal, n. - (drveni) ugljen drawback, n. - nedostatak, mana, vigilant, adj. - budan; oprezan maintenance, n. - uzdržavanje; održavanje foul, v. - uprljati, onečistiti EXERCISES A. Find the differences between American and British gallons in your dictionaries and find their equivalents in litres. B. Find three passive sentences in the text and copy them below. C. Translate the passage into Croatian.




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HYDROLYSIS

Hydrolysis brings about a chemical change. It occurs when a molecule of water joins another compound. In digestion, the water molecule hooks up with fats, proteins, and carbohydrates. The resulting reaction causes the breaking of chemical bonds. The fats, proteins and carbohydrates separate into their various subparticles. The subparticles are molecules small enough to diffuse through the intestinal membranes. The hydrolysis of maltose is a simple example of this digestive process. Maltose is a complex sugar. Let's say that a molecule of water combines with a molecule of maltose. In the resulting breakdown, two molecules of glucose emerge. Glucose, a simple sugar, diffuses through membranes. Here is the equation for the hydrolysis of maltose:

Maltose + water -------------> glucose + glucose C12H22O11 + H2O-----------> C6H12O6 + C6H12O6

/Maltose plus water yields glucose plus glucose or 2 molecules of glucose./ Hydrolysis is just one example of a chemical reaction that takes place in a laboratory. This process, for example, is used commercially to manufacture glucose (in the form of syrup) from starch. The equation for the hydrolysis of starch is:

(C6H10 O5)n +NH2) --------------> NC6H12O6 The n represents a variable; it indicates that the exact number of molecules is not the same for all such reactions. GLOSSARY bring about, v. - uzrokovati, izazvati hook up, v. - zakvačiti take place, v. - događati se, odvijati se sugar cane - šećerna trska sugar beet - šećerna repica EXERCISES A. 1. Sucrose is table sugar. It is obtained from sugar cane and sugar beet. Say something about its hydrolysis. 2. What is the formula for sucrose? Write it down. 3. What does maltose yield when it undergoes hydrolysis? 4. Is hydrolysis important in candy making? B. Complete the following sentences with the following words:




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subparticles, variable, digestion hydrolysis. 1. Chemical change is brought about by means of ....................... . 2. The water molecule hooks up with fats, proteins and carbohydrates in ................... . 3. Molecules small enough to diffuse through the intestinal membranes are called ...................... . 4. A ...................... indicates that the exact number of molecules is not the same for all such reactions. C. Find the equivalents in meaning from column A and B. A B 1. occur a. connect (with) 2. hook up (with) b. appear 3. emerge c. give, result in 4. yield d. take place D. Join the correct sentence beginnings and sentence endings A B 1. Sucrose is obtained a. a complex sugar. 2. Hydrolysis brings about b. from sugar cane and sugar beets. 3. Maltose is c. a molecule of water joins another compound. 4. It occurs when d. a chemical change. E. Complete the following sentences referring to the text: 1. Chemical change is brought about by means of __________________. 2. The water molecule hooks up with fats, proteins and carbohydrates in _________________ . 3. Molecules small enough to diffuse through the intestinal membranes are called __________________ . 4. The equation for the hydrolysis of maltose is: _______________________. 5. _____________________ indicates that the exact number of molecules is not the same for all such reaction.




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ACIDS

1. An acid is a compound containing hydrogen which can be replaced directly or indirectly, by a metal. 2.Its solution in water turns blue litmus red. 3. Acids can be classified into two groups. 4. Acids which always contain the element carbon are called organic acids and they often come from growing things, like fruits. 5 Citric acid, which is found in lemons and oranges and other citrus fruits, and acetic acid, which is found in vinegar, are organic acids. 6. Acids which do not contain the element carbon are known as inorganic acids. 7. They are usually prepared from non-organic matter. 8. Inorganic acids consist of hydrogen and the chloride radical. 9. Hydrochloric acid consists of hydrogen and the chloride radical, and sulphuric acid consists of hydrogen and the sulphate radical. 10. They are inorganic acids.

a) All acids contain hydrogen. b) Inorganic acids contain the chloride radical. c) Organic acids always come from growing things.

11. The hydrogen in an acid is replaceable by a metal. 12. Acids can be divided into classes according to the number of atoms in each

molecule which a metal can replace. 13. Those which have only one replaceable hydrogen atom in each molecule are known as monobasic acids. 14. Other acids may contain either two or three such replaceable hydrogen

atoms in each molecule and these are known as dibasic and tribasic acids respectively.

15. All the atoms of hydrogen in the molecules of inorganic acids are replaceable by a metal.

16. Sulphuric acid is an inorganic acid which is monobasic. 17. Orthophosphoric acid, an inorganic acid whose molecules contain three

atoms of hydrogen, is tribasic. 18. Acetic acid molecules each contain four hydrogen atoms but only one of

these can be replaced by a metal. 19. Acetic acid is monobasic.

e) A molecule of hydrochloric acid contains one atom of hydrogen. f) Inorganic acids are monobasic. g) Hydrochloric acid is the only monobasic acid. h) A molecule of sulphuric acid contains three atoms of hydrogen. i) Orthophosphoric acid is an inorganic acid.




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EXERCISES A. Read the text carefully and then fill in the Croatian equivalents for the following: organic acid ................................ inorganic acid ................................ citric acid ................................ acetic acid ................................ hydrochloric acid ................................ sulphuric acid ................................ B. Fill in the Croatian equivalents for the following: monobasic acid ................................... dibasic acid .................................... tribasic acid ..................................... orthophosphoric acid ..................................... C. Contextual reference 1. In sentence 2, its refers to: a) acids b) hydrogen c) metal 2. In sentence 4, they refers to: a) acids b) organic acids c) inorganic acids 3. In sentence 10, They refers to: a) Hydrogen and the chloride radical b) Hydrogen and the sulphate radical c) Hydrochloric acid and sulphuric acid 4. In sentence 13, Those refers to: a) classes b) acids c) atoms 5. In sentence 18, these refers to: a) acetic acid molecules b) the four hydrogen atoms c) atoms




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D. Rewrite the following sentences replacing the underlined words with expressions from the text that have the same meaning. 1. All the atoms of hydrogen in the molecules of inorganic acids are replaceable by a metal. 2. Acids which do not contain the element carbon are known as inorganic acids. 3. Acids can be divided into classes according to the number of atoms in each molecule which a metal can replace. 4. Sulphuric acid has two replaceable hydrogen atoms in each molecule. 5. Ortophosphoric acid contains three atoms of hydrogen in each molecule. 6. Orthophosphoric acid, whose molecules contain three atoms of hydrogen, is tribasic. E. Relationships between statements Place the following expressions in the sentences indicated. Replace and reorder the words in the sentence where necessary. a) can be defined as (1) b) are classified as (5) c) for example (9) d) therefore (10) e) however (15) f) whereas (16,17) g) although (19) h) therefore (20)




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Test A. Translate the following text into Croatian

FOLIC ACID

Folic acid was first obtained in pure form from 4 tons of spinach leaves. Consequently investigators derived its name from the Latin word folium meaning leaf or foliage. Folic acid, the parent compound, is made up of three compounds linked together: 1) pteridine, a yellow pigment; 2) para-aminobenzoic acid; and 3) glutamic acid, an amino acid. Folic acid is not present in foods nor is it active as such in the body because it must be changed in body tissues to coenzyme forms before it can be used. Only 25-50 percent of the foalcin in food appears to be absorbed. Once it crosses the intestinal mucosal cell it is carried to the liver. Part of it accumulates in the liver while the remainder is distributed via blood to all parts of the body. body cells convert it to various coenzyme forms. B. Find two sentences written in the passive and copy them in the space below. C. Description of an element: HYDROGEN 1. State of aggregation: gas 2. Color, odor: colorless, odorless 3. Molecular weight: 2.016 4. Density: 0.08988 g/dm3 at stpx = 1 atm/OoC 5. Melting point: -259.14oC 6. Boiling point: -257.7oC 7. Solubility in water: 21.5 ml/dm3 water at 1 atm OoC 8. Occurence: everywhere 9. Atomic number: 1 10. Valency: 1 (monovalent) 11. Atomic weight: 1.008 12. Reactivity: at room temperature not very reactive; reactivity increases in the presence of a catalyzer ( xstp = standard, temperature, pressure = standardne okolnosti)




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D. The information below is given in a disorderly manner. Write it down correctly and guess what element it is about.

______________________

........ silver gray, odorless ........ 630 K = -273.15oC

........ no molecular weight ........ mono- and di-valent

........ not very reactive ........ 80

........ liquid at room temperature ........ 13.600 g/dm3

........ not soluble ........ 200.6

......... 234.3K = -273.15oC

....... usually as a sulphide; can be elemental




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TEST

A. Read the description of nitric acid and then write a similar description of sulphuric acid based on the notes provided.

Nitric Acid Nitric acid is a colorless, fuming liquid with a boiling point of 80oC. It has the chemical formula HNO3. It is a powerful oxidizing agent. It attacks most metals, producing fumes of nitrogen oxide. Its low boiling point indicates that it is highly volatile. The reaction of nitric acid with organic substances produces important compounds such as TNT and celluloid. It is also widely used in the fertilizer industry.

B. Notes on sulphuric acid: colorless, oily, bp 338 old name - oil of vitriol formula - H2SO4 extremely corrosive reacts strongly with water ---------- heat ------ this property used in drying not volatile cheapest acid - used in many industries (incl. manufacture of phosphate fertilizers, detergents, explosives) Now write a description of sulphuric acid: Sulphuric Acid




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TREATMENT OF THE LABORATORY SAMPLE

1. When it arrives at the laboratory, the sample often requires further treatment

before it can be analyzed, particularly if it is a solid. This usually involves decreasing the size of particles to a few tenths of a millimeter and through mechanical mixing.

2. In dealing with solid samples, a certain amount of crushing and grinding is ordinarily required to decrease the particle size. Unfortunately, these operations tend to alter the composition of the sample.

3.Several factors may cause changes in the composition of the sample as a result of grinding. Among these is the heat that is inevitably generated, which can cause losses of volatile components in the sample. In addition, grinding increases the surface area of the solid and thus increases its susceptibility to reactions with the atmosphere.

4. The moisture content, and thus the chemical composition, of a solid is frequently altered considerably during grinding and crushing. Both increases and decreases can occur. Decreases of water content are sometimes observed during the grinding of solids containing water in the form of hydrates. Undoubtedly, the change is a result of localized heating during the grinding and crushing of particles. More commonly, perhaps, grinding is accompanied by an increase in adsorbed water results.

5. Intermittent screening often increases the efficiency of grinding. In this operation, the ground sample is placed upon a wire or cloth sieve that will pass particles of the desired size. The residual particles are then returned for further grinding; the operation is repeated until the entire sample passes through the screen. It is obvious that grinding must be continued until the last particle has been passed. The need for further mixing after screening is also apparent.

GLOSSARY - TREATMENT OF THE LABORATORY SAMPLE decrease, v. - smanjiti (se), opadati, slabiti crush,v. - zdrobiti, gnječiti alter, v. - promijeniti susceptibility, n.- osjetljivost increase, n. - rasti, povećavati, povećati, umnožiti decrease, n. - smanjivanje, opadanje due to - ovisno o intermittently, adv.- povremeno, u razmacima screen, v. - prosijati kroz grubo sito wire, n. - žica cloth, n. - sukno, tkanina sieve, n. - sito, rešeto residual, adj. - koji preostaje, rezidualan screen, n. - grubo sito, rešetka, zaslon grind, ground, ground, irr. v. - samljeti, smrviti




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EXERCISES A. Translate the text into Croatian. B. a. Paragraph 1, sentence 1: What kind of sentence is it? Discuss the verbal forms in sentence 1. b. Paragraph 2. Underline all the gerund forms. c. Paragraph 3. Copy all the modal auxiliaries. d. Paragraph 4. 1. Underline and copy two sentences with verbs in the passive voice. 2. Copy all the gerund forms. 3. Decide whether the words increases and decreases are nouns or verbs in this paragraph. 4. Copy all the adverbs in this paragraph. e. Paragraph 5. Describe all the verbal forms in this paragraph.




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LABORATORY SAFETY

Most accidents in the laboratory can be avoided if a few precautions are taken. Since it is difficult to say when accidents will occur, a number of rules must be followed at all times. These rules are listed below. 1. Always wear safety glasses (goggles) in the laboratory. 2. Never work alone in the laboratory. Being alone in a situation in which you may be helpless is suicide. 3. All organic chemicals can be toxic if sufficient quantities are taken in. Always use the hood when working with toxic materials. Treat no chemical lightly. Remember that many chemicals can enter the body through the skin, as well as through the mouth or lungs. 4. Use no open flames near flammable solvents. Fire can be avoided by not lighting a burner until you are completely sure that no one near you is handling a flammable material. Ether is particularly dangerous. 5. Keep flammable solvents in flasks rather than in open beakers. Keep gas and water valves closed except when these utilities are needed. 6. Never heat an enclosed system and never completely close an assembly of apparatus in which a gas is being evolved. 7. Keep your laboratory place clean. If you spill any of your materials, clean it up immediately. 8. Study the procedures which should be followed in case of any accident. Be especially informed of antidotes which are available for the chemicals you will be handling. GLOSSARY - LABORATORATORY SAFETY precautions - mjere opreza safety glasses - zaštitne naočale take in, v. - uzeti, unijeti, konzumirati burner, n. - plamenik handle, v. - rukovati flammable, adj. - zapaljiv valve, n. - ventil utility, n. - pomagalo flask, n. - tikvica beaker, n. - laboratorijska posuda; boca enclosed system - zatvoreni sistem assembly of apparatus - sklop aparature evolve, v. - hlapiti, odvajati se, razviti se spill, v. - proliti procedure, n. - procedira, uputa antidote, n. - protuotrov EXERCISES




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A. Translate into Croatian: 1. Use no open flames. 2. Treat no chemicals lightly. 3. Keep no flammable solvents in open beakers. B. Choose the right definitions for the given words: - utilities - medicine used against poison - precautions - substance able to dissolve another substance - antidote - services such as the supply of water, gas, etc. - solvent - care taken in advance to avoid risk C. Look at the text carefully and complete the following sentences. Accidents occur: 1. when you do not ....................... 2. if you ............................................... 3. if a) ........................... , b) ..............................., c) ........................ 4. if you use ...................................... 5. if you keep ................................... 6. if you heat .................................... 7. if you spill ...................................... 8. if you are not informed ................................................................... D. Translate into English: 1. Ne držite zapaljive otopine u otvorenim bocama. 2. Ne radite s otvorenim plamenom. 3. Zaštitite otrovne materijale ako ih ostavljate u laboratoriju.




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THE CELL

MILESTONES

1869 Elegant experiments with pea plants enable Austrian monk Gregor Mendel to describe the mechanisms of heredity. 1944 Working with the bacterium that causes pneumonia O.T. Avery of Rockefeller University and colleagues discover that genes are made of DNA. 1953 The double-helix structure of DNA is discovered by Francis H.C. Crick and James D. Watson. 1965 RNA is used to achieve protein synthesis in a test tube. Scientists demonstrate that sequences of three nucleotides specify amino acids to be linked together to form proteins by the ribosomes. The genetic code is cracked. 1970 Hamilton Smith and Daniel Nathans of Johns Hopkins University discover and use a new class of restriction enzymes, the chemical scissors that slice and separate DNA molecules. 1972 Paul Berg and others at Stanford University combine the DNA from two viruses, a technique that yields what is called recombinant DNA. 1973 Stanley Cohen of Stanford and Herbert Boyer of the University of California at San Francisco insert recombinant DNA into host bacteria that reproduce, or clone, the foreign DNA. The age of genetic engineering begins. 1977 Genetech, one of the first genetic engineering companies, embarks on the

biosynthesis of important drugs by recombinant DNA methods. 1977 Frederic Sanger of the British Medical Research council and Walter Gilbert of Harvard University independently discover techniques for the rapid sequencing, or reading, of the order of nucleotides in DNA molecules. 1978 Sickle-cell anaemia is diagnosed before birth of an infant by analysis of its DNA. 1982 Human insulin produced by recombinant DNA techniques. GLOSSARY - THE CELL - MILESTONES elegant, adj. - gladak, jednostavan pea, n. - grašak monk, n. - redovnik, fratar heredity, n. - naslijeđivanje pneumonia ,n. - upala pluća gene, n. - gen double-helix, n. - dvostruka uzvojnica achieve, v. - postići, dosegnuti test tube, n. - epruveta. kušalica crack, v. - puknuti, slomiti, razbiti, probiti scissors, n. - nožice, škare slice, v. - razrezati na komade, separate, v. - razdvojiti, odvojiti combine, v. - spojiti insert, v. - ubaciti, ugraditi embark, v. - upustiti se sickle-cell anaemia - srpasta anemia




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EXERCISES A. Answer the following questions: 1. Who was the first to describe the mechanisms of heredity? 2. What did O.T. Avery and colleagues discover in 1944? 3. Where was the existence of DNA discovered? B. Now you proceed in the same manner. Ask your colleagues to answer as many questions as you can think of. Q: A: Q: A:

GLOSSARY Antibody - A protein that binds to an invading antigen prior to the destruction of the antigen. Antigen - a foreign substance, usually a protein, that triggers

the body's production of a specific antibody directed against the antigen. Bacterium - A single-celled micro-organism with a primitive nucleus. Chromosome - A segment of DNA containing many genes. Clone - One or more genetically identical organisms. DNA - Deoxyribonucleic acid, the stuff of which genes are made, a long chain like molecule composed of nucleotides. E.Coli - Escherichia coli - A common intestinal bacterium, studied by generations of biologists, that has probably provided more knowledge of biochemistry and genetics than any other living thing. Enzyme - A protein that catalyzes one of life's chemical reactions. Gene - A segment of DNA containing the code information for making a specific protein. Hormone - A substance secreted by one type of cell that carries a signal to another type of cell. Monoclonal antibodies - Identical antibodies cloned from a single source and targeted for a specific antigen. Nucleotide - Building block of the DNA molecule composed of an organic base, a sugar, and a phosphate. Plasmid - A self-replicating circular DNA molecule found in bacteria and carrying two or more genes.




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Protein - A molecule of linked amino acids. Proteins serve primarily as biochemical catalysts and as structural

parts for an organism. Recombinant DNA - A new combination of genes spliced together on a single piece of DNA. EXERCISES A. Match the name in column A with the appropriate description in column B. A B Enzyme a protein that binds to an invading antigen Gene a substance secreted by one type of cell Protein a foreign substance triggering the body's production of antibodies Antibody the stuff of which genes are made Plasmid a protein that catalyzes a life's chemical reaction Antigen a segment of DNA with the coded information Bacterium a molecule of linked amino acids Clone a single-celled micro-organism Hormone a new combination of genes spliced together on a single piece of DNA DNA a self-replicating circular DNA molecule Nucleotide a segment of DNA containing many genes Chromosome one or more genetically identical organisms Recombinant DNA building block of the DNA molecule

B. Now put as many questions as you can to your colleagues. Start with: What, Which, How, Do, Does, etc. C. Now speak out a definition and let your colleagues guess the name or vice versa speak out a name and let your colleagues say the definition.




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THE CELL

The human body is composed of some hundred thousand million cells, each of which is complete in itself. These cells are grouped together in the body to form tissues with special functions. The largest component of a cell is its nucleus, and this is surrounded by a watery fluid called cytoplasm. It contains a network of membrane-like material - the endoplasmic reticulum - which is studded with small dark bodies known as ribosomes. The cytoplasm also contains a number of bodies, among which are the egg-shaped mitochondria and the smaller lysosomes. The complex activities needed to sustain life take place within the body's cells, and we may liken the activity of a cell to that of a chemical factory in which a great variety of raw materials is processed and converted into finished products. In a single cell many different raw materials are required, though they are largely composed of only four elements: carbon, hydrogen, oxygen and nitrogen. The processing stage, which is concerned with the conversion of these simple raw materials into the much more complex substances required to carry out the many functions of the cell, involves thousands of different reactions. Each of these reactions comprises many steps which must be carried out in a definite sequence with the result that the chemical operations of a cell are much more complicated, and need much greater integration, than those of a chemical factory. In order to sustain life the cell's activities must be controlled and organized into a self-regulating and self-renewing pattern. But how can such control be achieved? The answer is to be found in the existence of a group of crucially important substances called enzymes. Enzymes control all the chemical changes, that is the metabolism, which occur in living cells. They regulate the building up of anabolic reactions that result in the formation of complex substances such as proteins from single building units. They also regulate the breaking down or catabolic reactions that result in release of energy. The role of enzymes can be better understood when it is realized that each step is controlled by its own enzyme. The fact that different cells perform different functions is explained in terms of the enzymes that are present. About a thousand different enzymes have been recognized in the body, but in any one cell only a selection are present. Even so, most cells contain about 200 different enzymes, each of which is responsible for controlling a particular step. The complement of enzymes present in a cell automatically selects and controls those reactions which are to take place.




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CLASSIFICATION OF ENZYMES The substance upon which an enzyme acts is called the substrate, and enzymes are usually named after this substance. Thus the enzyme that acts on urea is called urease and that which acts on maltose is called maltase. It is a general rule that enzymes are named after the substrate upon which the enzyme acts, and given the suffix -ase. But, there are some exceptions, such as pepsin, tripsin and others that were named before the rule was formulated and accepted. The five main groups of enzymes are shown in the following table. Of these the first two are the substrate, that is its reaction with water. Oxidases control the oxidation of the substrate, and this usually takes the form of removal of hydrogen. NAME REACTION CATALYSED GENERAL EQUATION Hydrolases Hydrosysis AB+H2O ---------> AOH+ BH Oxidases Oxidation ABH2 ----------> AB + 2H Isomerases Intramolecular rearrangement ABC -----------> ACB Transferases Transfer of a group AB+C -----------> A + BC Synthetases Addition of one molecule to another A + B -----------> AB EXERCISES A. Make sentences using the words given below: 1. cell's activity / liken / chemical factory 2. raw material / process / finished products 3. reaction / comprise / step / definite sequence 4. sustain life / cell control / organize B. Find out which definition describes each part of the cell listed below and write the name of the part in front of the definition: nucleus; lysosome; mitochondrion; ribosome; cytoplasm; protoplasm 1. _______________ A cellular organelle that contains various hydrolytic enzymes. 2. _______________ Any or the RNA - rich cytoplasmic granules that are sites of protein synthesis. 3. _______________ The center of activity in a cell. 4. _______________ The protoplasm of a cell inside the nuclear membrane.




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5. _______________ Round or long organelles, found outside the nucleus, which produce energy for the cell. 6. ________________ A matter of life. C. Translate into Croatian: 1. group together - 2. surrounded by - 3. membrane - like material - 4. largely composed of - 5. concerned with - 6. definite sequence - 7. the answer is to be found - D. 1. Translate Paragraph 1 into Croatian: 2. Paragraph 2: a) Write down the plural of the word nucleus _____________ b) Give the Croatian equivalent for membrane-like __________________ c) Find in your dictionaries the best Croatian equivalent for the word studded and then translate the Paragraph 2. 3.Paragraph 3. liken - compare - a) Write down the missing words of the same origin: variety, n. ----------------------------, v. ----------------------------, adj. process, v. ----------------------------, n. ----------------------------, adj. b) Find the sentence in the text describing the activities within the cell and copy it in the space bellow.




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c) Translate Paragraph 3. 4. Paragraph 4. a) Translate into Croatian: processing stage -------------------------------------- concerned with ---------------------------------------- comprise ------------------------------------------------- steps ----- ------------------------------------------------- carry out - ------------------------------------------------ (definite) sequence ----------------------------------- integration ------------------------------------------------ b) Translate Paragraph 4: 5. Paragraph 5. a) Translate into Croatian: in order to -------------------------------------------------- self-regulating -------------------------------------------- self-renewing ---------------------------------------------- pattern ---------- -------------------------------------------- the answer is to be found ------------------------------- crucially important enzymes---------------------------- Translate Paragraph 5. 6. Paragraph 6. a) Translate into Croatian: result in something ------------------------- result in release of ------------------------- b) Translate Paragraph 6. E. After you have read the text again translate into English:




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1. Faza prerade uključuje tisuće raznih reakcija. 2. Enzimi kontroliraju razgradnju kataboličke reakcije. 3. Najveći sastavni dio stanice je jezgra. 4. Jezgra je okružena vodenkastom tekućinom koja se zove ... 5. Za normalnu funkciju, stanici su potrebne mnoge sirovine.. 6. Prerada je, u stvari, pretvaranje sirovina u gotove proizvode.




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PROTOPLASM

1. All protoplasm consists of certain chemical substances. It is not a definite,

fixed substance, but a moving, living material, constantly undergoing changes. Usually, under a microscope, it shows up as a greyish, semi-transparent, semi-liquid mass. It resembles uncooked egg white. Sometimes it takes on the appearance of a jelly or of a sticky semisolid. At other times, it assumes an oil-like state.

2. Protoplasm is a colloid. A colloid is a gelatinous substance consisting of extremely small particles suspended in another material. A colloid is a suspension. Protoplasm is a suspension consisting of water and various elements. This colloidal suspension can vary in appearance depending upon the amount of water and other materials in a particular sample.

3. Although scientists have identified the ingredients of protoplasm, they have been unable to make it in their laboratories. Somehow, it has been impossible to combine all the protoplasmic elements in just the right way.

4. On average, protoplasm consists mostly of oxygen, carbon, hydrogen and nitrogen. These four elements account for 95% of the total weight of an average quantity of protoplasm. Almost all protoplasm also contains calcium, chlorine, sulphur, potassium, sodium, magnesium, iodine and iron. Trace elements occasionally get into protoplasm along with the intake of food. Protoplasm found in one part of a living thing, differs from the one found in another part of the same organism. These differences are reflected in chemical make up.

GLOSSARY protoplasm, n. - protoplazma undergo, underwent, undergone, irr. v. - proći, podvrći se transparent, adj. - proziran semi - polu liquid, adj. - tekući, u tekućem stanju resemble, v. - nalikovati, biti sličan take on, v. - preuzeti, zauzeti, poprimiti appearance, n. - izgled suspended in - u suspenziji jelly, n. - želatina, žele sticky, adj. - ljepljiv assume, v. - poprimiti, preuzeti identify, v. - identificirati, prepoznati ingredient, n. - sastojak, sastavni dio, sastojina average, adj. - prosječan on the average - u prosjeku account for - otpadati na, imati trace elements - elementi u tragovima occasionally, adv. - povremeno, ponekad intake, n. - unošenje, konzumiranje chemical makeup - kemijski sastav




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make up, n. - sastav, građa, struktura occur, v. - događati se, odvijati se, odigrati se dominant, adj. - dominantan unique, adj. - jedinstven bond, n. - veza capable of, adj. - sposoban za link up - vezati tie,v. - vezati, povezivati bind, v. - vezati unite,v. - povezivati chemical bonding - kemijska veza, povezivanje share, v. - dijeliti; imati zajedničko tend to,v. - imati tendenciju; obično; u pravilu outer,adj. - vanjski shell, v. - ljuska attract,v. - privlačiti nucleus, n. pl: nuclei - jezgra similarly, adv. - slično tome ordinarily, adv. - obično convenient, adj. - prikladan plane, n. - ravnina

stick out, v. - stršati angle, n. - kut to some extent - u nekoj mjeri bring about - izazivati, stvarati, dovoditi do readily,adv. - spremno, lako greyish, adj. - sivkast reddish,adj. - crvenkast bluish, adj. - plavkast consisting of = which consists of depending on = which depends on containing = which contains EXERCISES A. Give the Croatian equivalents for the following: certain chemical substances constantly undergo changes take on the appearance vary in appearance depend upon the amount identify the ingredients




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B. Choose the correct answer: a) all 1. Protoplasm consists of b) no chemical substances. c) certain a) cooked 2. Protoplasm resembles b) uncooked egg white. c) fresh a) an acid. 3. A colloid is b) a compound. c) a suspension. C. Pair letters with figures to get logical sentences: LETTERS FIGURES a. A colloid is 1. with other atoms b. Protoplasm found in one part of 2. the symbols of the a living thing elements are joined together by lines. c. Protoplasm 3. a gelatinous substance. d. In a structural formula 4. is a colloid. e. Carbon joins readily 5.differs from the protoplasm found in another part of the same organism. D. Find synonyms in columns A and B and write letters in front of the figures. A B ___ 1. readily a. look like ___ 2. link b. different ___ 3. occasionally c. show ___ 4. resemble d. easily ___ 5. various e. bond ___ 6. indicate f. sometimes




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E. Translate into English: 1. Njihov izgled ovisi o količini vode u uzorku. 2. Živa tvar neprestano doživljava promjene. 3. Pod mikroskopom se vidi kao plavkasta masa. 4. U prosjeku, ona se uglavnom sastoji od kisika i vodika. 5. Katkada poprima izgled želea.




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THE LIVING CELL

All cells are different. There is no such thing as two identical cells, or as a typical cell. Cells vary in size, shape and arrangement. They differ in function. One kind of cells serves a different purpose than another kind of cells. Each has its own place within an organism. In spite of these differences, all cells have basic similarities. All cells are made of protoplasm. Protoplasm is the substance of life. Being alive, a cell is never at rest. In fact, all cells share a common trait in their function and activity. Each contributes to the energy you need for breathing, walking, thinking and living. Chemical reactions are constantly going on within a cell. Each reaction needs energy. Every cell consists of two basic subdivisions. One or these fundamental areas within a cell is the nucleus. The other part is the cytoplasm. Recent studies indicate that there is much chemical activity on the border of the nucleus and the cytoplasm, with parts of each sometimes extending into the other. The nucleus and cytoplasm are within a container which is known as the cell membrane. The nucleus is a control center. It contains genes and chromosomes. They control all the activities of each individual cell. They determine the basic characteristics of an organism. A cell reproduces, that is, it gives birth to a new cell. All the cells in our bodies are reproducing themselves. The genes and chromosomes make sure that a new cell is like the original cell from which it came. The genes and chromosomes are found in a part of the nucleus known as the chromatin. Ordinarily, the chromatin has the appearance of a fine network of threads. At the time of cell division, it becomes apparent that this network consists of separate threads, which are the chromosomes. In reality, the chromosomes do not come together to form a network. They exist separately. Different chromosomes have different shapes. Many show up as short, slender rods. Others are curved. For example, they may have the shape of the letter S or the letter J. Genes are within the chromosomes. By staining a cell with a dye, scientists can bring the chromosomes into view under the lenses of a microscope. The genes are too small to be seen under a microscope, but experimentation has fully established their existence. Every cell contains thousands of genes. Each gene determines the identifying characteristics of an organism. Genes dictate the colour of your eyes, the shape of your nose, the size of your foot, etc. You inherit such features from your father and mother. Inherited traits and features are passed from parents to child through genes in chromosomes. Chromosomes are made of protein molecules and of a substance known as nucleoprotein. Biologists believe that genes may possibly contain some nucleoprotein. However, it could be that genes are deoxyribonucleic acid molecules. DNA is an important biological code. The DNA molecules specify the traits that will be passed along from a parent to a child. The nucleus of a cell also contains spherical bodies known as nucleoli in the nucleus. These tiny, round bodies show up as dark splotches when the cell is stained. The stain makes them darker than other parts of the nucleus. The nucleoli are manufactured by a certain chromosome within the nucleus. This chromosome releases material that collects into a nucleolus. All the nucleoli disappear during cell division.




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Thus, a chromosome within a new cell must manufacture its own nucleoli. It is strongly believed that nucleoli contain a compound known as RNA. The nucleoli discharge RNA into cytoplasm. RNA picks up the genetic information /traits of inheritance / laid down by DNA. The nucleus is bounded by a nuclear membrane. Materials flowing into and from the nucleus must pass through it. DNA, for example, is filtered through the membrane when it leaves the nucleoli and flows into the cytoplasm. The nuclear membrane is much like the cell membrane. It is a multilayered structure consisting of protein and fat. The nuclear membrane shows up under the microscope as an extremely thin wall separating the nucleus from the cytoplasm. Cytoplasm is a semi-fluid. At times this changing substance is like a jelly, at other times it becomes watery. As a living portion of the cell, cytoplasm of course, is made up of protoplasm. Biologists look upon the cytoplasm of a cell as an area rather than as a single substance. It contains several separate structures: mitochondria, the Golgi bodies, vacuoles, plastids, ribosomes and the endoplasmic reticulum. The mitochondria of various cells take various shapes. A mitochondrion can be short and rodlike. Or, in a different cell it can be a long filament. But, whatever its shape, a mitochondrion is a center of much activity. It is the "powerhouse" of the cell, a place where energy is released. A cell has a specific job to do. The function of a nerve cell differs from that of a muscle cell. Some cells use more energy than others. Cells demanding much energy contain many mitochondria. A cell may have as few as fifty mitochondria or as many as five thousand. To produce energy, these cellular power plants must, of course, have fuel. Their fuel is food in the form of acids. Various acids work their way into the mitochondria just as gasoline flows into the carburettor of an internal combustion engine. These acids are first produced through the digestive breakdown of fats, proteins and carbohydrates. /Glucose is a prime supplier/. The mitochondria remove carbon atoms from the acids, leaving water and carbon dioxide as waste products. With this breakdown of the molecules, energy is released. This chemical reaction is a form of oxidation known as respiration. In some respects it is similar to the simple burning /oxidation/ of a candle. Oxidation /respiration/ within the cell, however, differs in a significant way from an ordinary flame. In a cell, the energy in not released as heat. Instead, through a series of complicated steps, it is transferred to another substance. The substance receiving and storing this energy is known as adenosine triphosphate or ATP. ATP, then, releases this energy by breaking a bond. A compound known as a phosphate separates from the ATP. When the bond is broken, adenosine diphosphate is left. This substance is commonly referred to as ADP. Substances known as enzymes control and speed up the chemical reaction within the cell. They are contained in parts of the cytoplasm known as ribosomes. Ribosomes are microscopic granules. With the help of enzymes, they manufacture proteins. Thus the tiny ribosomes can be looked upon as "protein factories". The ribosomes are distributed along an irregular structure known as the endoplasmic reticulum. The endoplasmic reticulum consists of channels that connect the cell membrane with the nuclear membrane. Also




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among the living parts of the cell are the Golgi bodies, fatty materials shaped in various ways. Their function has not been fully explained, but they are most apparent in the cell of the glands. Biologists think they have something to do with the manufacture of glandular secretions. Many cells contain plastids. A plastid is an intricately structured storage center. Recent electron microscope studies show that folds of the cell membrane run through the cytoplasm, forming the endoplasmic reticulum. We call this a kind of skeleton. Clustered on the reticulum are the ribosomes, particles which synthesize proteins. The structure of plant cells The outer layer of a plant cell is called the cell wall. This is composed of a non-living material called cellulose. The inner surface of the cell wall is lined with a layer of protoplasm. The nucleus is embedded in this layer. The protoplasm which surrounds the nucleus is called cytoplasm. The cytoplasm sometimes contains chloroplasts. These are small bodies composed of proteins. The surface of the cytoplasm is covered with a cell membrane. The centre of a plant cell consists of a cavity called the vacuole. It is filled with fluid. The walls of a plant cell are often joined to other cells which surround it. The lining between the walls of two cells is called the middle lamella. Plant-animal cells Similarities: Both plant cells and animal cells contain nuclei. A plant cell contains a nucleus. An animal cell also contains a nucleus Differences: Plant cells contain vacuoles, whereas animal cells often do not have vacuoles. Animal cells, however, often do have vacuoles. THE LIVING CELL - GLOSSARY vary, v. - razlikovati se shape, n. - oblik arrangement, n. - raspored be at rest - mirovati trait, n. - crta, obilježje contribute, v. - doprinijeti cytoplasm, n. - citoplazma border, n. - rub, granica extend, v. - širiti se, pružati se container, n. - vrećica; posuda membrane, n. - membrana gene, n. - gen chromosome, n. - kromosom give birth, v. - roditi, dati




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make sure - osigurati; brinuti se (da), uvjeriti se, provjeriti chromatin, n. - kromatin network, n. - mreža thread, n. - nit, vlakno apparent, adj. - očit, vidljiv, jasan slender, adj. - tanak rod, n. - štapić stain, v. - obojiti dye, n. - boja establish, v. - ustanoviti, potvrditi, dokazati inherit, v. - naslijediti feature, n. - crta; karakteristika acid, n. - kiselina spherical, adj. - okrugao, kuglast, sferičan splotch, n. - mrlja release, v. - osloboditi, otpuštati ribonucleic, adj. - ribonukleinski storage, n. - pohrana, spremište, skladište discharge, v. - izbaciti, ispuštati, lučiti discharge, n. - iscjedak, pražnjenje, otpuštanje lay down, v. - planirati, odrediti bound, v. - omeđivati, ograditi, usmjeriti multi-layered, adj. - višeslojan, slojevit jelly, n. - želatina look upon, v. - gledati, smatrati, držati vacuole, n. - vakuola rodlike, adj. - štapičast filament, n. - vlakno, nit, powerhouse, n. - (električna) centrala muscle, n. - mišić power plant, n. - električna centrala fuel, n. - gorivo internal combustion, n.- nutarnje gorenje digestive, adj. - probavni breakdown, n. - razgradnja curved, adj. - zaobljen, zavinut ribbon, n. - traka flat, adj. - ravan; plosnat cylindrical, adj. - cilindričan rectangular, adj. - pravokutan tapering, adj. - koji se sužava (prema kraju) segment, n. - isječak, segment spherical, adj. - sferan, sferičan, okrugao, kuglast swelling, n. - oteklina, izbočina groove, n. - žlijeb, brazda, utor hook, n. - kuka ring, n. - prsten anterior, adj. - prednji posterior, adj. - stražnji




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evenly spaced - ravnomjerno raspoređen swelling, n. - oteklina, izbočina groove, n. - žlijeb, brazda, utor a transverse section - transverzalni, poprečni, dijagonalni presjek a longitudinal section- duljinski presjek Note! bacterium - pl: bacteria coccus - pl: cocci spirillum - pl: spirilla flagellum - pl: flagella nucleus - pl: nuclei nucleolus - pl: nucleoli mitochondrion - pl: mitochondria Something can be:rod -shaped

spiral-shaped square-ended

round-ended, etc EXERCISES: A. Complete these comparisons: a/....plant .....cells.....animal cells contain... and... b/ Plant cells always contain .................animal cells often............ c/ Plant cells are surrounded by ..... Animal cells ......., are not.... d/ In ...... plant cells.... animal cells, the nucleus..... by cytoplasm. e/ In .... the nucleus is embedded in the cytoplasm lining the cell walls, .... in .... it is connected to the cell walls by...... f/ In... the chloroplasts are spiral-shaped,......in....... they are round. B. Read the text carefully; give it an appropriate heading and translate it.

___________________________________ Bacteria are very small organisms with single cells. They can be divided into three groups according to shape. Cocci are spherical in shape. Some species occur in groups, some occur in chains, some have two cells joined together. Bacilli form bacteria are cylindrical or rod-shaped. Some are round-ended rods, others have square ends. Some bacilli have long flagella. Spirilla are spiral in shape. The bacterium which causes cholera is comma-shaped with a single flagellum.




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C. Translate into English: inverted flask - spherical flask beaker gas-jar conical flask test tube U-shaped tube a rod a spiral D. Arrange the following words into pairs of words with similar meaning: A B ___1. powerhouse a. vary ___2. differ b. dye ___3. stain c. power plant ___4. shape d. definite ___5. trait e.produce ___6. specific f. form ___7. manufacture g. feature ___8. apparent h. obvious E. Give the name for the parts of the cell described by the following sentences: 1. The nucleus and the cytoplasm are contained in it. --------------- 2. It contains genes and chromosomes. --------------- 3. It is semi - fluid. --------------- 4. It is the powerhouse of the cell. --------------- 5. When the cell is stained they show up as dark splotches. --------------- 6. It picks up the genetic information laid down by DNA. --------------- 7. Nucleoli contain that compound. --------------- 8. They control and speed up chemical reaction within --------------- 9. With the help of enzymes they manufacture proteins. --------------- 10. Fatty materials, most apparent in the cells of the glands. ---------------




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GENE SPLICING

Called gene splicing or recombinant DNA (deoxyribonucleic acid), it is a way to redesign the genetic composition of an organism. This new technology has devised methods to produce insulin for diabetics, enzymes to dissolve blood clots, and gene transplants to combat genetic disorders. DNA is the blueprint of any organism and is made up of genes that are strung together to form the DNA chain. A gene is a small unit that is responsible for one piece of information in the chain. In human beings, for example, one gene may determine the color of the eyes and another the shape of a person's nose. Every living organism has DNA, which determines the growth and function of the cells. Each organism has its own distinctive genetic composition. In gene splicing, scientists use special enzymes to break a DNA molecule apart at specific places between genes. At the specific place, the scientists may or may not remove a gene. The next step is to add a new gene or group of genes from some other organism. After the new set of genes is added, the molecule is put back together. The new DNA molecule now functions with new instructions and begins to reproduce itself. Because scientists still do not completely understand the total effect of gene splicing, they conduct most experiments on organisms such as bacteria. A one-celled germ found in the colon, E.Coli, is frequently used in gene splicing experiments. Some valuable discoveries have resulted from gene splicing. Besides those already mentioned in the first paragraph, one recent discovery was a hormone (human growth hormone) used to treat dwarfism. Interferon, a protein produced by the body to fight infection, has been reproduced through gene splicing. Some scientists hope that it will be useful in treating cancer. Because quantities are limited, however, interferon is still very expensive, so its use is limited. Some scientists believe that the nutritive value of plants could be improved by the injection of new genes. Others feel that the same value could be achieved with livestock. In industry, bioengineers are developing special genes to use against pollutants in water or to help extract crude oil from exhausted wells. Some people are critical of gene splicing. They are afraid that gene splicing is unethical because it changes the blueprint for life. Other critics believe it is possible that gene splicing will create "monster" - type substances. The answer to the concerns of the critics cannot be given because DNA is still being researched. Basically, the issue is social in nature. Science seeks to be pure, while the applications of a scientific discovery are social, governed by the attitudes of people.




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GLOSSARY - GENE SPLICING splice, v. - sastaviti dva kraja, povezivati, kanelirati, spojiti blueprint, n. - plan, nacrt, ovdje: genska karta string, strung, strung, irr. v.-vezati, nizati break apart, v. - razdvojiti, razderati, odvojiti, raskinuti add, v. - dodati, zbrojiti put together, v. - složiti, sastaviti dwarf, n. - patuljak treat, v. - liječiti cancer, n. - rak, karcinom livestock, n. - stoka, blago pollutant, n. - zagađivač extract, v. - ekstrahirati, izvući, iscijediti, istisnuti crude oil - sirova nafta exhaust, v. - iscrpiti well, n. - izvor, vrelo for life - zauvijek basically, adv. - u osnovi seek, v. - tražiti, težiti pure, adj. - čist a scientific discovery - znanstveno otkriće govern, v. - upravljati attitude, n. - stav, pristup matrix, n. - matrica EXERCISES A. Identification: Identify or define the following: DNA - gene - interferon - B. Completion: Complete the following statements using information from "Gene Splicing". 1. _____________ are strung together to form the DNA ___________, which is the ______ of any organism. 2. A new technology that redesigns the _______________composition of an organism is called _________ ______________. 3. DNA determines the _____________ and _______________ of cells and gives each its own distinctive genetic ________________ . 4. In gene splicing a DNA _______________is broken apart by special__________and sometimes a new ____________ is added which functions with new ____________ and begins to ______________ itself.




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5. A protein that fights infection, called _________________, is a product of gene splicing and is used to treat _______________ . 6. Injecting a new _________________ in plants, some scientists believe, could improve their ______________ value. C. True - False: Write + if the statement is true and 0 if it is false and then correct the false statements to make them true. ________ 1. Gene splicing has already produced some "monster" - type

substances. ________ 2. Special genes are being developed to fight pollution in water. ________ 3. Some bioengineers work with exhausted oil wells to stimulate

production of crude oil by using special genes. _________4. Interferon determines the color of a person's eyes and the shape of his nose. _________5. E.Coli, a famous bioengineer, developed a special gene splicing machine. _________6. Gene splicing has produced a hormone that can treat

dwarfism. _________7. Deoxyribonucleic acid is the blueprint of any organism. _________8. DNA uses special enzymes that are found in the colon. _________9. Recombinant DNA is a term used instead of gene splicing. ________10. Some of the concerns about splicing are more social than scientific. Now correct the false statements: D. Word Study I. From column B select the word or expression equivalent in meaning to those in column A. Place the letter of your answer in the blank. A B _____ 1. devise a. absolute _____ 2. make up b. precise _____ 3. mention c. refer _____ 4. govern d. feeling _____ 5. method e. development _____ 6. growth f. yet _____ 7. place g. control _____ 8. effect h. invent _____ 9. function i. location




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_____10. specific j. way _____11. total k. purpose _____12. still l.period _____13. attitude m. compose _____14. stage n. result II. Form verbs from the following nouns and then write a sentence, using the verb in the Past or Past perfect Tense with an object. The first one is done as an example. 1. composition/ to compose Science has composed blueprints for gene splicing. 2.transplant/ ___________________________________________________ 3.shape/ ___________________________________________________ 4.splicing/ ___________________________________________________ 5.instruction/ ___________________________________________________ 6.experiment/___________________________________________________ 7.discovery/____________________________________________________ 8.injection/_____________________________________________________ 9.application/___________________________________________________ E.Grammar Practice Cloze Practice: Fill the blanks with the missing words and then check your answers by referring to paragraphs 5 and 6 in the reading. Because scientists still do __________ completely understand the total ___________ of gene splicing, they __________ most experiments on organisms ___________ bacteria. A one-celled ____________ found in the _______________, E. Coli, is frequently _________in gene splicing experiments. _____________ valuable discoveries have resulted _______________ gene splicing. Besides those _____________ mentioned in the first ______________, one recent discovery was_____________ hormone (human growth hormone) used to treat ______________. Interferon, ______________ protein produced by the ____________ to fight infection, has ____________ reproduced through gene splicing. ________________ scientists hope that it ___________ useful in treating___________. Because quantities are limited, _____________, interferon is still very ____________, so its use is ____________ . F. Definitions: There are several definitions in the text. Find them and copy them in the space below.




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Control text

A GENE IS CLONED

The recombinant molecule can be inserted into the bacteria that are to act as factories manufacturing the desired protein. By far the most popular choice of bacterial host is an organism known as Escherichia coli (E. coli). The predominance of this bacterium in genetic engineering is partly an accident of history. Molecular biologists have studied this particular species for decades, and as a result, more is known about the inner workings of this microscopic creature than about any other organism, including humans. The plasmids were chosen because they have an inherent ability to enter the cells of E. coli, and this invasion can be facilitated by adding a few simple chemicals to the mixture. Plasmids posses another property which is of great value to biotechnologists - they can make copies of themselves. Once inside a bacterial cell, a single plasmid can multiply itself to yield up to a few dozen identical replicas. If the plasmid contains a human gene, then that gene is copied along with the rest of the molecule. As the bacterium which harbours the plasmids is also growing and dividing - as often as once every twenty minutes - each daughter cell takes with it a few of the plasmids, which again reproduce themselves. Before long, a single bacterium will have given rise to millions of descendants. A population of cells all derived from a single ancestor is called a clone, and all cells in a clone have the same genetic make-up. Thus, within a day or so a single bacterium carrying a recombinant molecule will yield millions of identical cells, all of which contain the original human gene, and the gene is then said to have been cloned. EXERCISES A. Consulting your dictionaries finish the glossary. You will have to add to the list below. GLOSSARY - A GENE IS CLONED recombinant - along with - host - to give rise to - by far - insert - to yield up to - dominant - predominance - inherent - facilitate - multiply - replica - harbour -




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daughter cell - descendant - ancestor - genetic make-up - B. Answer the following: 1. Write down what you already know from your previous knowledge about Escherichia coli. 2. How is a gene cloned? 3. What is the role of plasmids in gene cloning. C. Grammar revision. 1. Find all the sentences in the Present Perfect Tense and copy them in the space below. (Remember when and why the Present Perfect Tense is used.) 2. Find all the sentences in the Passive form and underline them. When it is possible transform them into the Active.




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HELLO, DOLLY

CLONING AND ITS TEMPTATIONS

With the publication of a paper in Nature on February 27th, 1997, a Scottish sheep called Dolly became the most famous sheep in history. The reason is that she is the first mammal to have been cloned from the tissue of an adult animal. Despite the public anxiety that the advent of Dolly has stimulated, she has not sprung from nowhere. People have been trying (but failing) to clone animals from adult tissues for decades. Moreover, the creators of Dolly, Ian Wilmut and his colleagues at the Roslin Institute, near Edinburgh, used their technique to clone their first sheep back in 1995. The difference is only that their previous experiment used the cells of an embryo rather than an adult. A clone is an organism that is genetically identical to another. Mammals, all of which reproduce sexually, do not clone naturally, except into identical twins. Unlike many other organisms, adult mammals cannot clone themselves.

The making of a clone

The simplest way to clone a mammal is to copy what happens during the formation of identical twins. In the earliest stages of development, when the egg has divided into only a few cells, each is identical and none has yet taken on any special tasks. Each, if it becomes separated from the others, has the ability to grow into a complete being. Human identical twins grow this way by accident; in animals, scientists have frequently split early embryos deliberately. Dolly, though, is a bit different. Until now mammals have usually been cloned by "nuclear transfer". This involves fusing two cells together: a donor cell containing all of its DNA, and an egg cell from which the DNA has been removed. Removal of DNA from an egg is a precise but not difficult operation, and has been done routinely for years. Once the two cells have been fused (a process usually encouraged by a small electric shock), the developing embryo is installed in a surrogate mother. Until now, however, growing viable adult mammals using this technique has been impossible, unless the donor cell is taken directly from an embryo. Attempts to clone mammals from older cells consistently ended in failure, with glaring chromosomal abnormalities all too apparent. Until Dr Wilmut and his colleagues published their most recent paper, no one was sure whether this happened because older differentiated cells had switched off some genes permanently, or because no one had found a means of making them feel at home in an egg. The key to Dr Wilmut's success lays in co-ordinating the states of the donor cell and the recipient egg. During the cycle by which a single cell grows before dividing (in what is known as mitosis) into two daughter cells, it passes through three phases, known as G1, s and G2. During the s phase the chromosomes are copied, doubling the amount of DNA in the cell, so that




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when the cell splits each of its daughters receives the same amount of DNA the parent started with. Without this doubling, each daughter cell would inherit only half of the parent cell's DNA, and after a few generations each descendant cell would have only a fraction of the genetic information present initially. This means that when the cell enters the G2 phase it has twice as much DNA as it needs just to do its job. Previous attempts to clone mammals have typically used donor cells in the s or G2 phase, and an egg cell that is already starting mitosis. In principle, this should work: the egg is already prepared to split in two cells, and either the s or G2 phase should provide the right amount of DNA for this to occur smoothly. For some reason it does not. When the two cells fuse, a bit more DNA replication takes place. This snarls up mitosis, producing useless, broken chromosomes. So Dr Wilmut and his colleagues tried something different. Instead of using a donor cell that was actively going through the cell cycle, they used a cell that was quiescent. That is, a cell which just after splitting, has stopped all further activity. Quiescence occurs naturally in some cells - but Dr Wilmut and his colleagues induced it in their donor cells by starving them of nutrients. This caught the cells right at the start of the cell cycle, it meant that they had the normal amount of DNA. Moreover, it meant that the donor cells were more similar to the eggs in other respects too. During the cell cycle, different proteins accumulate, and the molecular make-up of a cell alters. The use of a quiescent rather than actively growing cell kept the rest of the cellular environment in tune with the one in the egg. When the two cells fused, development could go on normally. Last year, Dr Wilmut and his colleagues showed that this technique could work on cells taken from early embryos that were then grown for several generations in the laboratory. In this, they were also the first: previously, in order to work, nuclear transfer had to be done using fresh embryonic cells. And now they have shown that the DNA from three kinds of more mature tissue - older embryonic tissue, fetal tissue, and tissue from an adult - can still direct the development of a complete organism.

An old Dolly

The technique is far from perfect. Out of 277 fused pairs of cells where the donor cell was from adult tissue, only one - Dolly - survived. Indeed, out of a total of 834 fused pairs, only eight lambs were born, and one of these died immediately after birth. Nonetheless, it is now clear that the cloning of an adult mammal is possible. From a scientific point of view, three questions are now of special interest. Will Dolly and her remaining companions survive to adulthood? Will they age normally? And how easy would it be to use the same technique to clone other mammals? During the growth and development of an organism, cells differentiate. Heart cells become different from nerve cells, which are different in turn from blood cells, and so on. Until Dolly, it was not at all clear whether or not this differentiation took place through the permanent inactivation or disabling of genes irrelevant to being a heart cell or a nerve cell. In some ways, it is still




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not clear. Dolly was grown from just one kind of cell taken from the ewe's udder; DNA from other cells, especially nerve cells, may not be able to recover all of its functions. However, Dolly's existence suggests that at least in some cases, it is possible to develop a viable offspring from a single adult cell. Dolly is still young, however. Her genetic mother was six years old, and the DNA in her mother's cells had been replicated many times. During DNA replication, mistakes are sometimes made. Apparently none was bad enough to prevent Dolly from coming into being. But cloning experiments with amphibians typically failed to grow a clone from adult tissue into anything beyond a tadpole. Dolly's ability to survive will be of great interest. The big scientific (as opposed to ethical) question about Dolly is how she will age. For not all of the DNA important in an organism's development is contained in the nucleus. A fraction of it is outsourced to components of the cell known as the mitochondria. Once upon a time, the mitochondria were free-living bacteria. Now they provide energy for the hosts. Without them, cells cannot survive for long. In mammals, mitochondria are inherited just from the mother. Indeed, every egg cell contains hundreds of mitochondria, which are parcelled out among the daughter cells during the initial cell division. Mitochondria carry their own genes, but not all the mitochondria in a cell carry the same genes. And during the lifetime of an organism, the balance of mitochondrial DNA can shift. In humans, diseases such as Alzheimer's, Parkinson's and some forms of diabetes are one consequence of this shifting. The fusion of an old cell with a genetically unrelated egg raises two concerns. One is whether the mitochondria from the two cells will be compatible. Given Dolly's survival so far, it suggests that they are. But the bigger issue is whether the mitochondria that Dolly inherited from her mother will, by dint of having shifted in balance during the mother's life, shorten Dolly's or expose her to mitochondrial diseases. Since Dolly achieved stardom, many words have been spilled over the desirability of cloning humans. But it is still by no means certain that the technique that worked in her case can be used to clone other mammals. Dr Wilmut expects that it should be possible in pigs as well (despite the fact that pig embryos do not do well when they are put in a Petri dish instead of a womb). But Colin Steward, an embryologist at the National Cancer Institute, in Frederick, Maryland, reckons that the technique may not be easy to transfer directly to mice, or to humans. This is because even if the DNA from the donor cell retains all of its functions, it may still need to be "reprogrammed" before it can conduct the development of a new organism. That is, the switches that turn genes on or off need to be modified. Dr Steward points out that the DNA in a sheep's embryo does not start running the show until the egg has divided three or four times (i.e., into 8 or 16 cells). In mice, it must start up immediately after the first cell division and in humans after the second. This may not give the DNA enough time to prepare. Mice are no doubt the next target. Some biologists dearly want to clone adults, and it would be much easier to experiment on cloned mice than cloned




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sheep. But whether or not anyone should be allowed to make similar efforts to clone humans is going to be a subject of much debate. GLOSSARY - HELLO, DOLLY mammal, n. - sisavac adult, adj. - odrastao anxiety, n. - zabrinutost advent, n. - dolazak, prispijeće spring, sprang, sprung, irr.v. - iskočiti, niknuti, nastati task, n. - uloga, svrha split, split, split, irr.v.- razdvojiti, podijeliti, otcijepiti, raskoliti, kalati surrogate, n. - surogat, nadomjestak viable, adj. - koji se može održati na životu, sposoban za

život switch off, v. - prekinuti vezu, prespojiti, ugasiti snarl, v. - mrsiti, zaplesti, zamrsiti, quiescent, adj. - miran, koji miruje, nepokretan quiescence, n. - mirovanje fuse, v. - pomiješati se, stopiti se; rastaliti, rastopiti disable, v. - onesposobiti, učiniti neupotrebljivim ewe, n. - ovca (ženka) udder, n. - vime offspring, n. - potomak come into being - oživjeti tadpole, n. - punoglavac outsource, v. - izniknuti, proisteći host, n. - domaćin parcel out, v. - prenijeti, prenositi, predati by dint of - pomoću womb, n. - maternica, utroba dearly, adv. - skupocjen, vrijedan EXERCISES A. Number the paragraphs and give each paragraph a key word or words. B. Answer the following questions: 1. Who is Dolly?




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2. What is she famous for? 3. Who made her famous and why? 4. Where is the Roslin Institute? 5. When and where was the first sheep cloned? 6. What is a clone? 7. Can some organisms clone themselves? 8. Can mammals clone themselves? 9. What can cloning be compared to?

10. Have any mammals been cloned until now?

11. How were they cloned?

12. What is the difference between cloning mammals until now and cloning of Dolly?

13. Describe the process of cloning Dolly.

14. What is quiescence and why is it important in cloning?

15. How many cells were cloned in the experiment where Dolly was the only survivor?

16. From a scientific point of view what are the questions of special interest now? 17. When do the cells differentiate?

18. How and when does this differentiation take place?

19. What kind of cell was used for growing Dolly? 20. How will Dolly age?




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21. Explain the origin and the role of mitochondria. 22. Which diseases in humans are one of the consequences of mitochondrial DNA shift?

23. Which other animals are likely to be cloned next? 24. What is "reprogramming"?




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Genetic engineering

DOLLY - "A FARMYARD FREAK" Within hours of her public debut last week, Dolly the cloned sheep was lambastered as a "farmyard freak" and harbinger of genetic doom. France's farm minister, Philippe Vasseur, spoke darkly of six-legged chickens and eight-footed sheep following behind Dolly in quick succession. President Clinton has given an advisory panel of experts just 90 days to come up with proposals for government action. The government could prohibit the cloning of human beings or issue regulations limiting what researchers can do. But the government cannot control the actions of individuals or private groups determined to clone humans for whatever purpose. And science has a way of outstanding all ethical restraints. "In science, the one rule is that what can be done will be done", warns Rabi Moses Tendler, professor of medical ethics at Yeshiva University in New York. He opposes cloning on Biblical grounds. Some ethicists regard the cloning of humans as inherently evil, a morally unjustifiable intrusion into human life. Others measure the morality of any act by the intention behind it; still others are concerned primarily with the consequences -for society as well as for individuals. Father Richard McCormick, a veteran Jesuit ethicist at the University of Notre Dame, represents the hardest line: any cloning of humans is morally repugnant. Though many see her as a dangerous scientific precedent, Dolly is not the first genetically engineered creature to hit the headlines, nor the most fantastic. Transgenic animals - those whose DNA has been fiddled to include foreign genes or to remove existing ones are now common place in academic laboratories and biotechnology firms. They are, essentially, living test tubes that allow scientists to model human diseases, try better treatments and generate larger quantities of useful proteins more cheaply than ever before. Compared with goats making human antibodies, pigs producing human clot-busting factors and designer mice, Dolly is a humdrum scion basking in the celebrity of her unusual origins. Almost 20 years ago, some of the first transgenic mice - a species beloved of biologists - were created by injecting human DNA into the nuclei of newly fertilised mouse eggs. These delicate injections were performed under a microscope using hair-thin glass needles to deliver the genes and the slightest hint of pressure to hold the egg in place. As scientists hoped, the mice that developed from these manipulated embryos included the foreign DNA in their own chromosomes and then passed it on to their offspring, generation upon generation. Want to know how changes in certain genes cause cancer? Build a mouse with mutant p53, a gene that normally produces a tumour-suppressing protein, and hunt for tumours. Need to know if excessive amyloid tangles cause Alzheimer's disease? Easily done by supplementing your mouse-to-be with the gene for the human protein and watching for signs of brain breakdown in the adult. Dying to learn if antibodies are essential to protect against certain parasitic infections? Just blot the genetic blueprint in your




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transgenic mouse, thereby "knocking out" the enzyme used to make antibodies in the first place, and see how the parasite and its host square off. Such transgenic mice (and some rats as well) are rightly prized for the information they provide on disease and development. But their small size and short life-span makes them better living test tubes than walking factories. When it comes to producing rare and valuable human proteins for medical therapy, scientists have chosen to trade up to a larger model. Using microinjection techniques, a barnful of transgenic species has been developed to secrete milligrams of human protein in their milk, hundreds or thousands of times more than could be gathered directly from people or from genetically manipulated cells grown in the lab. At Genzyme Transgenic Corporation in Farmingham, Massachusetts, special goats have been designed to produce human antithrombin III, a protein that controls blood clotting. Antithrombin III harvested from the goats' milk looks exactly like the human protein and behaves the same, at least in the test tube. Clinical trials, now in progress, will show if it can help patients undergoing coronary bypass surgery who are particularly vulnerable to excessive clotting and the dangers of thrombosis. Near Edinburgh, transgenic sheep at PPL Therapeutics and the Roslin Institute, Dolly's home, have been busy churning out human alpha-1-antitrypsin. Clinical trials have begun to test the safety of this protein on healthy volunteers. If all goes well, tests will begin on cystic-fibrosis patients shortly. Much of the damage to their lungs and pancreas is due to a runaway enzyme in their bodies, called elastase, as it was the case in earlier animal experiments. PPL Therapeutics has also had success in creating cows which spike their own milk with human alpha-lactalbumin, a nutrient supplement or "nutraceutical". Although transgenic cattle can give high yields of the desired protein, they are slow to reproduce. Instead, many scientists have grown partial to transgenic pigs. They are all the rage in xenotransplantation, where porcine tissues engineered to resist human immune responses are seen by companies such as Imutran, in Britain, as a likely source of replacement organs for patients. By contrast, William Velander's pigs at Virginia Polytechnic and State University in Blacksburg will never come under the knife. He and William Drohan at the American Red Cross in Rockville, Maryland are milking their designer pigs for precious (and profitable) human blood products such as Factor VIII and fibrinogen. One block to large-animal engineering is that the most revolutionary technique in mouse transgenics - called embryonic stem cell technology - does not work in many other mammalian species. This means that while it is possible to produce the mouse of your dreams, selection in other animals is limited. This is frustrating for scientists trying to develop more reliable animal models of human disease or to use such technology to improve animal health or agricultural output. Nuclear transplantation, Dolly's immaculate conception, may be one way of overcoming this barrier in sheep and other species. Present company not included?




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EXERCISES A. Check the words in your dictionaries and write your own glossary. GLOSSARY - DOLLY - A FARMYARD FREAK B. After reading the passage again write an essay on the moral and ethical issues on cloning. How useful may it be and what dangers can it produce.




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PROTEINS

Proteins make up about 15% of protoplasm. They are the chief building materials of protoplasm, and thus, the body itself. They are essential nutrients and a necessary part of everyone's diet. Protein manufacture occurs in all body cells. Every protein molecule contains carbon, hydrogen, oxygen and nitrogen. Some proteins also contain some elements as potassium sulphur and iron. These long protein molecules have a complicated structure.

AMINO ACIDS Proteins are made up of smaller units called amino acids. There are more than one hundred amino acids known to exist in nature. Of the total, 23 are found in proteins. Each protein molecule has a characteristic number and arrangement of amino acids. An amino acid itself, of course, is a molecule. Thus, each amino acid consists of specific elements in a definite combination. There are basic elements present in every amino acid. These basic elements are carbon, hydrogen, the amino group which has the symbol NH2, and the carboxyl group, which has the symbol COOH. Thus, the general formula for an amino acid is:

H

------------- C --------------COOH

NH2 Amino acids join together in living organisms to form protein molecules. This manufacture of protein is constantly going on, for the amino acids are highly reactive. At the same time proteins are also breaking down into amino acids. When they are linked in protein molecules, the link is always between the carbon (C) of the COOH group and the nitrogen (N) of the NH2 group. In the reaction, the OH of the COOH group and the hydrogen atom of the NH2 group are removed. They join together to form water. Thus, water is a by-product of the reaction that produces proteins from amino acids.

THE MAKING OF A PROTEIN

The simplest amino acid is glycine. Two glycine molecules can come together to form a simple, two-chain protein. This protein is known as glycyl glycine. The structural formula of an amino acid chain appears at first to be very complicated. However, a careful reading shows that we are involved only with building blocks. All the pieces fall into place.

NUCLEIC ACID

The chemistry of living things is known as biochemistry. All the chemical reactions that take place in a plant or animal cell are biochemical reactions. They involve an interplay between matter and energy, the rearranging of atoms and molecules, and the emergence of new materials along with the disappearance of others. A living organism is like a factory that keeps taking in raw materials and turning out new products. All the biochemical reactions




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taking place within a living organism are carefully controlled. There are even blueprints that give the final results of these reactions. These blueprints are nucleic acids. One important nucleic acid is known as deoxyribonucleic acid, or DNA.

CARBOHYDRATES

About 1% of protoplasm is made up of carbohydrates. A carbohydrate is an organic compound containing carbon, hydrogen and oxygen. The term carbohydrate indicates the elements which these compounds contain. There are two kinds of carbohydrates: sugar and starch. They play an important part in the biochemical processes that release energy. Thus, as nutrients, sugar and starch provide energy for the body.

KINDS OF SUGARS

The sugar in candy is known as sucrose. It is just one of several kinds of sugar. The various types are classified as simple sugars, double sugars and complex sugars. Among the simple sugars are glucose, fructose and galactose. The double sugars are sucrose, maltose and lactose. Cellulose is a complex sugar.

STARCH As a carbohydrate, starch is made up of carbon, hydrogen and oxygen. it is a product of green plants. such foods as bread, potatoes, corn, rice, spaghetti and macaroni contain starch. foods containing starch are in the diet of people everywhere. Like sugar, starch is a fuel nutrient. That is, it provides heat and mechanical energy for the body. But carbohydrates are lacking in such nutrients as proteins, minerals, vitamins.

FATS

Fat, too, is a fuel nutrient. A fat is rich in energy. When a fat is broken down in the digestive process, energy is released. We get vegetable fats from such plants as corn, peanuts and soybeans. Animal fats are found in cream, butter, lard, eggs, bacon, and other meats.

PROTEINS - DESCRIPTION OF AN EXPERIMENT What is needed: sugar, egg white, nitric acid, ammonium hydroxide, gas burner, goggles Put sugar in one test tube and egg white in the other. Label each test tube. Carefully cover the sample in each test tube with concentrated nitric acid. Do not get nitric acid on your hands. Wear goggles to protect your eyes. Heat each sample until it boils. Use the gas burner. Make sure the mouth of the test tube is pointed away from your body. Be careful. Do not point the test tube toward someone else. Let the sample boil by passing the test tube in and out of the flame. Then remove the test tube from the flame. Remove the acid from each sample by pouring it carefully into some water. Let the test tube cool. Then add a little ammonium hydroxide do each sample. A pale yellow indicates the presence of protein. The brighter the yellow, the greater is the amount of protein in the sample.




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GLOSSARY - PROTEINS protein, n. - bjelančevina essential, adj. - glavni, osnovni nutrient,n. - hranjiva tvar diet,n. - vrsta ishrane potassium,n. - kalij sulphur, n (sulfur) - sumpor iron, n. - željezo amino acid, n. - amino kiselina arrangement, n. - raspored, organizacija carboxyl group, n. - karboksilna grupa by-product, n. - nus-produkt blueprint, n. - šifra, plan, prvi otisak glycine, n. - glicin biochemistry, n. - biokemija interplay, n. - međusobno djelovanje emergence, n. - pojava, nastanak disappearance, n. - nestanak nucleic acid, n. - nukleinska kiselina deoxyribonucleic acid, n.-deoksiribonukleinska kiselina carbohydrate, n. - ugljikohidrat starch, n. - škrob candy, n. - bombon sucrose, n. - saharoza simple sugars - monosaharidi double sugars - disaharidi complex sugars - polisaharidi fructose, n. - fruktoza galactose, n. - galaktoza maltose, n. - maltoza lactose, n. - laktosa cellulose, n. - celuloza corn, n. - AmE - kukuruz; BrE - žito rice, n. - riža lack in , v. - nemati vitamin, n. - vitamin digestive process,n. - probavni proces peanut, n. - kikiriki soybeans, n. - soja lard, n. - svinjska mast bacon, n. - slanina goggles, n. - zaštitne naočale gas burner - plinski plamenik test tube, n. - epruveta, kušalica holder, n. - držač label, n. - etiketa label, v. - obilježiti sample, n. - uzorak




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make sure - pazite, provjerite nitric acid, n. - dušična kiselina ammonium, n.; pl: ammonia- amonijak EXERCISES A. Answer the following questions: 1. Why should you avoid getting nitric acid on your hands? 2. Why should you make sure the mouth of the test tube is pointed away from your body? 3. How can you make the sample in the test tube boil? 4. What indicates the presence of the protein in this experiment? 5. Name as many kinds of foods containing protein as you can remember. B. Write down the nouns with the same root as the verbs listed. V N e.g. to heat heat V N to sample to cover to concentrate to point to protect to color to indicate to test C. Complete the following sentences using the words from the text: 1. ______________are the building blocks of proteins. 2. Each protein molecule has a characteristic ______________ and____________of amino acids. 3. _________________ manufacture occurs in all body cells. 4. The simplest amino acid is _________________. 5. DNA is short for _________________________________________. 6. Cellulose is a ________________________ sugar. D. Translate into English: 1. Obilježite svaku epruvetu. 2. Zagrijte vodu do vrenja.




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3. Pustite da se epruveta ohladi. 4. Pazite da vam dušična kiselina ne kapne na ruke. 5. Pažljivo izlijte tekućinu u vodu.




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Control text PROTEINS, ACIDS, FATS

Proteins are an essential nutrient and a necessary part of everyone's diet. Protein manufacture occurs in all body cells. Every protein molecule contains carbon, hydrogen, oxygen and nitrogen. Some proteins also contain such elements as potassium, sulphur and iron. These long protein molecules have a complicated structure and many contain a million or more atoms. Amino acids are smaller units that proteins are made of. There are more than a hundred amino acids known to exist in nature. Of the total, about 23 are found in proteins. They can be looked upon as "building blocks" of proteins. Each protein molecule has a characteristic number and arrangement of amino acids. And there are thousands of different protein molecules. Each amino acid consists of specific elements in a definite combination. The basic elements present in every amino acid are carbon, hydrogen, the amino group and the carboxyl group. Amino acids join together in living organisms to form protein molecules. This manufacture of proteins is constantly going on, for the amino acids are highly reactive. At the same time proteins are also breaking down into amino acids... When they are linked in protein molecules the link is always between the carbon and the nitrogen. They join together to form water. Thus, water is a by-product of the reaction that produces proteins from amino acids. Nucleic acids. All the chemical reactions taking place within a living organism are carefully controlled. There are even "blueprints" that spell out the end results of these reactions. These blueprints are nucleic acids. One important nucleic acid is known as DNA. The DNA molecule, in theory, is shaped like a spiralled ladder. The "rungs" of the ladder are arranged differently in each individual DNA molecule. Billions of arrangements are possible. A carbohydrate is an organic compound containing carbon, hydrogen, and oxygen. The term "carbohydrate" indicates the elements that these compounds contain. There are two kinds of carbohydrates: sugar and starch. The sugar in candy is known as sucrose. It is just one of several kinds of sugar. The various types are classified as simple sugars, double sugars and complex sugars. Among the simple sugars are glucose, fructose and galactose. Sucrose, maltose and lactose are double sugars. Starch. As a carbohydrate, starch is made up of carbon, hydrogen, and oxygen. Foods containing starch are in the diets of people everywhere. Like sugar, starch is a fuel nutrient. That is, it provides heat and mechanical energy for the body. Starch helps to provide the energy you need for all your daily activities. It contributes energy to the life processes going on in all body cells. Sugar and starch are essential to life and to the health of the body. But carbohydrates are lacking in such nutrients as protein, minerals and vitamins. Starch undergoes a chemical change when it is digested. It is changed to sugars. The digestive enzymes cause the groups of carbon, hydrogen and oxygen atoms in a molecule of starch to separate. The separated atoms form glucose. Fats. On average, about 13 per cent of protoplasm, by weight, is made up of fats. Fat, too, is a fluent nutrient. A fat is rich in energy. When a fat is broken down in the digestive process, energy is released.




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All fats contain carbon, hydrogen, and oxygen. /most fat molecules consist of three molecules of fatty acids attached to one molecule of an alcohol known as glycerine. EXERCISES A. There are several definitions in the text. Write them down in the space below. B. There are several classifications that can be found in the text. Find them in the text and write them down in the space below. C. Translate the text.




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Control text Translate into Croatian:

PLASMIDS - THE MAGIC CIRCLES All the genes essential for the bacterium's survival are carried on its single, large, circular chromosomes. There are also much smaller circles of DNA inside some bacteria and these rings are known as plasmids. Plasmids are enigmatic structures and their functions are not entirely understood, although it is clear that many of them carry genes which enable bacteria to resist antibiotics. Plasmids have an odd relationship with the rest of the cell; most importantly for genetic engineering, they will often pass from one cell to another, even if the cells are of different species. Therefore, if plasmids are taken from one set of bacteria and the human cDNA gene is "stitched" into the plasmid ring, the plasmid's natural ability will allow it to enter bacteria and convey the human gene into its new home. A plasmid used in this way is called a vector, from the Latin word for carrier or bearer. Certain types of viruses can also act as vectors. To stitch the human gene into a plasmid we call upon the services of another type of enzymes, a restriction enzyme. All enzymes are remarkably precise tools, and in restriction enzymes their powerful ability to distinguish between similar structures is brought to a peak of perfection. Faced with a tangled mass of DNA, restriction enzymes scan the double helix until they recognize certain specific sequences of bases, and then make a precise cut across the two DNA strands In the case of a circular plasmid molecule, this opens the ring ready for the insertion of the human gene.




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DISTRIBUTION OF NUTRIENTS IN PLANTS

The green appearance of the water in ditches and lakes is caused by tiny, microscopic green plants called algae. Each of these plants consists of a single cell. Transport of nutrients in these plants is not much of a problem. The sugars and other products of photosynthesis are used in the very cell in which they are produced. In higher plants, which are very complex, the cell is usually more specialized. Many cells are so specialized that they cannot produce their own food for photosynthesis. Usually, root cells are colorless and must obtain their sugar from the green leaves of the plant. A considerable distance is often involved, so an efficient transport system is necessary. It is rare that one finds plants with green roots capable of photosynthesis. (One of these is Hydrocharis, a pretty floating plant of the ponds and ditches of Holland). It is generally believed by scientists that millions of years ago plant life originated in the water, and that gradually new forms of plant life developed that could live on land. This would not have been possible if an effective transport system had not evolved inside the plant to distribute food, water, and minerals. The development of such a transport system was the key to the great development of land plants. The giant sequoia tree, in California, sends down to the ends of its roots sugars that are made in the leaves hundreds of feet up in the air. And the ends of the roots may be a hundred feet away from the base of the tree. Plants have three systems that make possible a rapid interchange of substances among various parts of the plant body. Although all three systems involve different tissues, they do interconnect so that material may go from one system to the other. In addition to the food transport system, there is the water transport system and the air transport system.

FOOD TRANSPORT SYSTEM

The food transport system is the most delicate of the three. It is easily damaged because it is alive; that is, the cells through which the food is transported are biochemically active. Wounds, heat, and exposure of the plant to toxic chemicals all damage the system that transports food. If you cut off a branch and put it in water, it may seem alive for many days or even weeks; yet the food transport system stops functioning soon after the branch is cut off from the tree.

WATER TRANSPORT SYSTEM The water transport system is much less delicate than the food transport system. Water transport in stems takes place in long, strong capillaries. These are dead cells. During the last century, a German scientist cut down a tree and then placed the base in a tub containing picric acid. The yellow, poisonous acid moved up to the top of the tree. There it killed the leaves, but




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the water transport system was not affected by the poison. When you cut through a tree trunk or branch, you notice two different tissues: the bark, and the water transport system through the wood. These transport tissues wear out as the tree grows. So they are continually replaced. Every year new water-conducting vessels appear in new wood, and every year new food-conducting tubes appear in new bark. The tissue responsible for this rejuvenation is a very thin layer of delicate cells. These cells are in a cylindrical layer around the stem, between the wood and the bark, and they form a tissue called the cambium. The fast-growing cambium is ideally located to receive nutrients, having the food stream to its front and the flow of water and minerals to its back.

AIR TRANSPORT SYSTEM The air transport system is simply an interconnecting arrangement of air spaces between cells. This system is especially well-developed in marsh plants whose roots are not exposed to much oxygen. The leaves of marsh plants such as rush or mangrove can transport oxygen from the stomata through the stem to the roots, all within the body of the plant. Gas spreads fairly rapidly. The porosity of a leaf can be shown by a simple apparatus invented by Dr. Alvin. The instrument is designed to measure the condition of the stomata in leaves while they are still growing. In addition to air, other gases will enter plants through open stomata and invade the interior of the leaf through the air space between the cells. Smog is a poisonous gas, a product of heavy car traffic in sunny climates. When the stomata are closed, smog cannot enter and no damage is done. But if a cloud of smog rolls over plants on a sunny morning when the stomata are open, it will ruin the leaves of sensitive plants. Many vegetable growers have left metropolitan areas because of the smog. GLOSSARY - NUTRIENTS IN PLANTS distribution, n. - distribucija, raspored nutrient, n. - hranjiva tvar appearance, n. - izgled ditch, n. - jarak, graba photosynthesis, n. - fotosinteza efficient, adj. - efikasan, brz, djelotvoran float, v. - plutati pond, n. - ribnjak originate, v. - poticati (od, iz) evolve, v. - razviti, evoluirati sequoia, n. - sekvoja rapid, adj. - brz damage, n. - šteta wound, n. - ozljeda tub, n. - posuda, kada picric acid - pikrinska kiselina




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affected by - na koji ( loše) djeluje, utječe tree trunk - stablo, deblo bark, n. - kora drveta wear out, v. - istrošiti rejuvenation, n. - pomlađivanje stem, n. - peteljka, stabljika, deblo cambium, n. - kambij marsh, n. - močvara, močvarno tlo mangrove, n. - tropsko drvo, mangrovo drvo chamber, n. - komora porosity, n. - poroznost invade, v. - napasti interior, adj. - unutarnji smog, n. - smog ruin, v. - uništiti, oštetiti accurate, adj. - točan, precizan acquire, v. - steći obtain, v. - dobiti, postići rush, n. - rogoz alga, n.; pl: algae - alga stoma, n.; pl:stomata - puči interchange of substances - izmjena tvari EXERCISES A. Number the paragraphs. B. Paragraph 1. 1. Underline all the verbal forms. 2. Copy all the passive forms. 3. Copy all the participles. C. Paragraph 2. 1. Underline all the modal verbs and make a list in the space below.




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2. Copy two passive forms. D. Paragraph 3. 1. Make a chart of all the verbal forms in Paragraph 3. E. Paragraph 4. 1. Explain why is do used in the sentence: “Although all three systems involve different tissues, they do interconnect so that material may go from one system to the other”. F. Food Transport System Paragraph 5. 1. Underline all the passive forms. 2. Say what kind of sentence the following is: If you cut a branch and put it in water, it may seem alive for many days or even weeks;..... G. Water Transport System Paragraph 6.




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1. Underline and copy all the Past Simple forms active or passive. 2. Underline and make a list of all the participles. H. Air Transport System Paragraph 7. Discuss with your colleagues the verbal forms in Paragraph 7. Write an example for each. I. Draw a line under the correct ending of each sentence: 1. It is believed by scientists that millions of years ago life originated a) in the mountains b) in the water c) in the marshes 2. The green appearance of water in ditches and lakes is caused by a) algae b) gases c) picric acid 3. Many vegetable growers have left metropolitan areas because of a) traffic noise b) lack of sunshine c) smog 4. Usually root cells must obtain their sugar from a) chemicals in the soil b) the green leaves of the plant c) the capillaries 5. The distribution of nutrients in plant is called a) interchange b) rejuvenation c) transport 6. The cambium of a tree is located




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a) under the roots b) between the wood and the bark c) in the sap J. Three of four words on each line below are similar in meaning or have something in common. Draw a line under the word that does not belong with the others. 1. task, job, work, stem 2. evolve, grow, expose, develop 3. marsh, concept, idea, notion 4. nutrient, food, status, mineral 5. chemistry, porosity, philosophy, literature 6. complex, accurate, exact, correct 7. expand, enlarge, invade, increase 8. acquire, obtain, identify, secure 9. stomata, ditch, river, canal 10. vessel, tube, capillary, rejuvenation




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VEGETABLE OILS AND FATS Vegetables are the most important source of edible oils and fats. Most vegetable oils are liquid at 20o C, though there are a few notable exceptions such as palm oil, palm kernel oil and coconut oil which melt above this temperature. Soya beans are grown extensively in China and the USA and soya bean oil is now the most important edible vegetable oil accounting for about a quarter of all vegetable oil supplies. After the oil has been extracted from the bean, the residue left constitutes a valuable source of protein. Soya bean oil is the major vegetable oil used in margarine manufacture and large quantities are also used in cooking fats. Vegetable oils are normally extracted from seeds, kernels and nuts, either by mechanical pressure or by solvents. The latter method involves the use of a liquid solvent of low boiling point in which the oil is soluble. After the seed or nut has been ground, it is shaken with the solvent, the oil extracted and the solid residue left behind. When the liquid mixture is heated, the low boiling solvent evaporates, leaving the oil. The olive oil is a valuable source of oil, over a million tons of olive oil being produced annually. Olive oil is notable for the large proportion of unsaturated acids which it yields on hydrolysis and also for its purity. The finest olive oil may be used without purification and is used for all purposes in Mediterranean countries, while in Great Britain it is used as salad oil. REFINING OF CRUDE OILS Crude olive oil is exceptional in that it can be used for edible purposes without refining. Most vegetable oils, however, contain a number of impurities such as moisture, free fatty acids, colouring matter, resins, gums, and sometimes vitamins. The refining process is carried out in a number of stages. 1. Degumming Crude oils often contain impurities in suspensions which, in the presence of water, forms gum. The impurities are removed by adding hot water to the warm oil, which is then transferred to a centrifugal separator. The separator revolves at a high speed and the gum particles, which have a higher density than the oil, are thrown to the bottom of the vessel, leaving an upper layer of clarified oil. 2. Neutralizing Owing to spoilage, all crude oils contain a small proportion of fatty acid and low-grade oils may contain considerable quantities. The acids are removed by neutralizing the oil with a solution of caustic soda, which converts the fatty acid into an insoluble soap. The soap is then removed by allowing it to settle to the bottom of the neutralizing tank. If the impurity is palmitic acid, for example, insoluble sodium palmitate is formed.




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3. Washing and drying In order to remove the last traces of soap from the oil, it is washed with warm water. Two layers form, and the lower water layer is run off, leaving the oil layer, which is then dried under vacuum. In modern plant these separate stages are being replaced by a continuous automatic process in which the neutralizing stage is carried out much more quickly in a centrifugal separator. The oil is now clear and free from acid, but it is usually yellowish in colour and still has a distinct odour. It is, therefore, bleached and deodorized. 4. Bleaching The oil is warmed and Fuller's earth and activated carbon are added. Both these materials have a large capacity for adsorbing colored matter. The mixture is stirred and a partial vacuum is maintained. When all the colored matter has been adsorbed, the oil-earth mixture is passed through filter presses from which the oil emerges as a clear colorless liquid. 5.Deodorizing The oil is heated under vacuum in a tall tank and steam is injected so that the liquid mixture is violently agitated. In one method it is sprayed upwards as an umbrella-shaped fountain, so that a large surface area of liquid is continually exposed, and the volatile, odoriferous substances and remaining free fatty acids are stripped from the oil. The oil is now pure and ready for blending. It is desirable that the oil should not come in contact with air once it has been refined, as this leads to deterioration due to oxidation. GLOSSARY edible, adj. - jestiv palm oil - palmino ulje kernel, n. - sjemenka, koštica, kost coconut, n. - kokos melt, v. - topiti se, rastapati se, postati tekućim soya bean, n. - zrno soje grow something - uzgajati extract, v. - izdvojiti, odvojiti, ektrahirati residue, n. - ostatak, talog seed, n. - sjemenka, sjeme, zametak kernel, n. - koštica; sjemenka, jezgra; sadržaj koštice, zrno

žitarice nut, n. - orah, orašasto voće, grind, ground, ground, v.irr. - mljeti, samljeti, drobiti shake, v. - tresti, protresti, pomiješati solid residue - kruti talog (ostatak) notable, adj. - poznat (po) evaporate, v. - ishlapiti




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saturated, adj. - zasićen unsaturated, adj. - nezasićen purification, n. - proćišćivanje crude, adj. - sirov refine, v. - rafinirati impurity, n. - nećistoća moisture, n. - vlaga free fatty acids - slobodne masne kiseline resin, n. - smola, biljni vosak gum, n. - biljna smola, kaučuk, guma carry out, v. - izvesti, provesti degumming, n. - uklanjanje smole ili voska revolve, v. - okretati se oko osi vessel, n. - posuda density, n. - gustoća, viskoznost clarified, v. - proćišćen, razbistren neutralize, v. - neutralizirati owing to - zbog, radi low-grade - loše kvalitete caustic soda - kaustična soda settle, v. - slegnuti se palmitic acid - palmitinska kiselina bleach, v. - izbijeliti, izbijeljivati, bijeliti Fuller's earth - Fullerova zemlja dedorize, v. - dezodorirati, ukloniti miris stir, v. - miješati emerge, v. - izaći, proizlaziti blend, v. - pakirati; flaširati EXERCISES A. Make a list of vegetable oils mentioned in the text. B. List the processes of refining crude oils:




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C. Find three examples for each verbal form listed in the text. GERUND PRESENT PARTICIPLE PAST PARTICIPLE 1. 2. 3.




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FAT IN THE BODY When fatty foods are eaten they pass through the digestive system. In the small intestine they are partly hydrolysed by lipase, one fatty acid molecule being split off from a fat molecule at a time, so that the result is a mixture of free fatty acids and mono and diglycerides. As the hydrolysis is not complete, little free glycerol is produced. A proportion of the fat is not hydrolysed at all, but is absorbed directly into the blood in a highly emulsified form. Although the exact mechanism of the digestion and absorption of fat is not fully understood, it is certain that about two hours after a meal the blood becomes "milky" in appearance due to the presence of emulsified fat, and that within another few hours this fat has disappeared from the blood. It might be supposed that once fat has been absorbed it would be oxidized directly to produce energy while the surplus would be transferred to the "reserve" and stored in the fat deposits of the body. Modern evidence, however, suggests a rather different sequence of events. After absorption, most of the fat is transported to the fat storage cells of the body and is not oxidized immediately. This seems to occur even when the body is in urgent need of energy. The fat deposits are not stable though; they are in a constant state of flux. In experiments carried out on rats fatty acids labelled with deuterium were fed to rats and within a week nearly half of the fat deposits were found to contain deuterium. This method of tracing the path of molecules during metabolism by labelling certain atoms with isotopes is known as isotopic tracer technique. The results show that fatty acids are rapidly interchanged between fats indicating that the latter are constantly broken down and resynthesized. When the body uses fat as a source of energy - which is mainly when there is a shortage of carbohydrate - the glycerol and fatty acids are oxidized. The breakdown of glycerol involves reaction with ATP to form glycerol phosphate which is subsequently broken down, in a series of oxidation steps, to carbon dioxide and water. The oxidation of fatty acids takes place in steps, a fragment containing two carbon atoms being removed in each step. If stearic acid is oxidized, for example, it is first broken down to palmitic acid, palmitic acid is then oxidized to myristic acid and so on, until butyric acid is reached. EXERCISES A. Give Croatian equivalents for the following groups of words: - partly hydrolysed - - one at a time - - it is not fully understood - - sequence of events - - this seems to occur - - label atoms with isotopes - - fat depots were found to contain - - it is subsequently broken down -




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B. Find synonyms for the following words and write them down: - proportion - - exact - - label - C. Find the right answer: a) through the stomach. 1. When fatty foods are eaten they pass b) through the liver. c) through the digestive system. 2. Fatty acids are partly hydrolyzed in a) stomach. b) small intestine. c) large intestine. 3. a) All the fat is hydrolysed. b) A portion of the fat is hydrolyzed. c) A portion of the fat is not hydrolyzed a) fully understood. 4. The exact mechanism of the digestion is b) not fully understood. c) completely understood. 5. After absorption most of the fat is transported to a) the fat storage cells of the body. b) storage cells. c) to the fat. 6. In experiments carried out on rats fatty acids labelled with deuterium were fed to: a) rats. b) guinea pigs. c) mice. a) fat. 7. The body uses fat as a source of b) energy. c) carbohydrates. a) in steps. 8. The oxidation of fatty acids takes place b) in fragments. c) in acids.




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D. Translate into Croatian: If energy is not required immediately, molecules of glycerol and fatty acid recombine and are deposited again as fat. There is, therefore, a dynamic equilibrium between the breakdown and rebuilding processes. When fats are metabolized at an abnormally fast rate, acetoacetic acid accumulates faster than it can be removed and its concentration in the blood increases. This condition may result from the use of diets containing too much fat and too little carbohydrate and it also occurs during starvation and in people suffering from diabetes.




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BACTERIA

Wherever life exists on the earth, from the bottom of the sea to the mountain tops, bacteria are found. They live in and on plants and animals, in water and on dust particles in the air. One ounce of ordinary soil may contain upwards of 100 million invisible bacteria. Of the several thousand known species, only about 150 cause disease. Thus their role in nature is more helpful than harmful. Bacteria are small, mostly under 1 micron in diameter. Bacterial cells are limited to three simple shapes: bacilli (rods), cocci (spheres) and spirilla (spirals). Bacteria reproduce by fission. After division the daughter cells may stay together in a colony whose structure - chain, cluster, sarcina, or other arrangement is determined by the plane of division. Structure of bacteria The small size and the absence of clearly visible nuclei once made bacteria seem like very simple organisms. However, new staining, breeding and biochemical methods, together with the electron microscope, now reveal how complex these little organisms really are. A cell wall composed of complex sugars is always present. The cytoplasm has a certain amount of structure. The cell has a membrane, whose folds dip into the cytoplasm. Ribosomes are abundant, as well as granules of food and other substances. There are no mitochondria, however, and the clumps of chlorophyll and other pigments are never contained within membrane-surrounded plastids as in cells of higher organisms. Many bacilli and spirilla swim by means of flagella, each consisting of two or three twisted strands of myosin-like protein. Each motile species has a typical arrangement of flagella. Many species have thick, slimy capsules, resembling those of blue-green algae. Spores Spores are heavy-walled structures, possibly protective, but not well understood, that form within certain bacilli. They can withstand the temperature of boiling water for hours. When conditions become favourable, the spore wall softens and the germinating bacterium grows out of it and resumes activity.




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Bacterial metabolism and its use Like other kinds of organisms, bacteria carry on metabolic activities. Their metabolism releases energy, as well as many kinds of waste products. Pigments in colored bacteria, toxins in deadly ones, and the useful products of fermenting organisms, are all by-products of metabolism. In many ways, bacteria are useful to man. We cultivate them to make vaccines, vitamins and antibiotics for medical use. Every waste product released by organisms has a bacterium -or a co-operating fungus - to dispose of it. Staining bacteria Robert Koch made it easier to examine bacteria when he invented methods of staining which are still in use. He used a loop of platinum wire to spread a smear of bacteria on a slide, passed the slide through a flame to kill and fix the microbes, and then colored them with aniline dyes. Since bacterial cells differ so little in shape, microscopic examination alone will not distinguish the many species. Differential stains are useful because various bacteria react differently to them. In the Gram stain (named after its inventor) the cells are dyed blue with crystal violet, then treated successively with iodine and alcohol. Gram-positive bacteria retain the blue color, while Gram-negative bacteria are decolorized. Nobody knows why the stain works. Yet the Gram reaction indicates important differences. Gram-positive bacteria have structurally simple cell walls containing little fat; penicillin is effective against them. Gram-negative organisms have layered cell walls with considerable fat; they respond to streptomycin but not to penicillin. In deciding on the diagnosis and treatment of a puzzling bacterial infection, Gram-staining is one of the first tests a doctor orders. A similar differential test, the acid-fast stain, is used to diagnose tuberculosis. GLOSSARY - BACTERIA bacterium, n. pl: bacteria - bakterija particle, n. - čestica bacillus, n. pl.: bacilli - bacil coccus, n. pl.: cocci - koki sphere, n. - kugla; sfera spirillum, n. pl.: spirilla - spirilli spiral, adj. - spiralan spiral, n. - spirala, uzvojnica fission, n. - dijeljenje; cijepanje cluster, n. - nakupina, grozd sarcina, n. - nakupina, paket koka




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arrangement, n. - nakupina, red plane of division, n. - ravnina diobe stain, v. - bojati nucleus, n. pl: nuclei - jezgra, nukleus staining, n. - bojanje breeding, n. - uzgajanje reveal, v. - otkriti, pokazati fold, n. - nabor dip, v. - uroniti abundant, adj. - brojan, obilan clump, n. - nakupina, grumen chlorophyll, n. - klorofil flagellum,n. pl: flagella - bič, flagela twisted, adj. - smotan, zavijen strand, n. - vlakno, nit myosin, n. - miozin motile, adj. - pokretan slimy, adj. - sluzav alga, n. pl.: algae - alga spore, n. - spora withstand, v. - izdržati germinate, v. - (pro)klijati, razvijati se metabolism, n. - metabolizam carry on metabolic activites - biti metabolički aktivan cooperating fungus - simbiotska gljivica loop, n. - eza; petlja smear, n. - razmaz Gram stain - bojanje po Gramu dye, n. - boja dye,v. bojiti puzzling, adj. - nejasan, nerazjašnjen decolorize, v. - gubiti boju acid-fast, adj. - otporan na kiselinu ounce, n. (oz) = six tenths of a pound = 28,35 gr EXERCISES A. Write down and pronounce the plural forms of the following nouns: 1. nucleus _________________ 2. virus _________________ 3. nucleolus _________________ 4. bacterium _________________ 5. coccus _________________ 6. bacillus _________________ 7. spirillum _________________ 8. alga _________________ 9. fungus _________________ 10. stimulus _________________




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B. Fill the blank in each of the sentences below with the appropriate word from the text which correctly completes the meaning: 1. Not all __________ of bacteria cause diseases. 2. Bacteria are very ______________ little organisms. 3. Koch invented methods of ______________ ___________ . 4. Bacteria reproduce by __________________ . 5. Spores can ________________ the temperature of boiling water for hours. C. Find one word expressing the meaning of the whole sentence and write it down in the space provided: 1. _______________ Substances produced by micro-organisms which interfere with the growth of other organisms. 2. _______________ Smallest unit of an element. 3. _______________ Rod-shaped bacteria. 4. _______________ The chemistry of living organisms. 5. _______________ Living outer layer of the protoplasm of a cell. 6. _______________ Spherical bacteria. 7. _______________ Substance which cannot be changed into any simpler form. 8. _______________ A form of reproduction in which the cell divides into two or more daughter cells.




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IRREGULAR FOREIGN PLURALS

Singular Plural alga algae quantum quanta nucleus nuclei phenomenon phenomena analysis analyses matrix matrices D. According to the examples above write the plural forms of the following words: Singular Plural spectrum ________________ synthesis ________________ bacterium ________________ criterion ________________ hypothesis ________________ formula ________________ fungus ________________ catalysis ________________ symposium ________________ bacillus ________________ radius ________________ axis ________________ equilibrium ________________ index ________________ E. Complete the following sentences using correct plural forms: 1. Each chemical element has its characteristic spectrum. Most elements give very complex ___________________ . 2. The mass of an atom is concentrated in its nucleus. In most atoms the ___________ are made up of protons and neutrons. 3. One criterion of a chemically pure substance is its color. Other ___________are its melting point and boiling point. 4. An interesting phenomenon was observed. Oxidation and reduction are basic chemical __________________ . 5. The scientists subject any hypothesis to test or experiment. Many ___________________ will have to be discarded. 6. The quantum theory states that radiant energy is emitted and absorbed in very small but definite portions which are called energy ______________ .




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MICROBES AS CHEMICAL MACHINES

In 1857 Louis Pasteur published a report showing that the souring of milk is caused by microbes which convert milk sugar into lactic acid. The process can be chemically expressed as follow:

C6H12O6 ---------------------->2CH3CHOHCOOH

(sugar) (lactic acid) In its gross result and in appearance this is one of the simplest chemical changes representing the breakdown of one molecule of sugar into two molecules of lactic acid. During the same period Pasteur studied alcoholic fermentation as exemplified by the conversion of grape juice into wine. In this case, micro-organisms were responsible for the change in yeast, which converts the sugar of grape juice into alcohol according to the following equation:

C6H12O6 ---------------------->2CH3CH2OH + 2CO2

THE PRESENCE OR ABSENCE OF OXYGEN When left exposed to the air, wine will turn into vinegar, and this is the next problem to which Pasteur turned. Hen showed that in this case the change is caused by another type of micro-organisms, the bacterium now called Acetobacter, which oxidizes alcohol into acetic acid according to the following formula:

CH3CH2OH + O2 -------------------->CH3COOH + H2O (alcohol) (acetic acid)

The conversion of sugar into lactic acid or alcohol occurs independently of the presence of oxygen, whereas the conversion of alcohol into acetic acid results from an oxidation in which atmospheric oxygen participates. Pasteur, however, observed that when a sugar solution was placed in an atmosphere from which the oxygen had been completely removed a very different kind of substance was likely to appear, namely butyric acid. Under these conditions, the bacteria which proliferate live best without oxygen and in fact may die in the presence of this gas. "Anaerobic" bacteria convert sugar into butyric acid.




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GLOSSARY - MICROBES souring, n. - kiseljenje convert, v. - pretvoriti, pretvarati lactic acid - mliječna kiselina breakdown, n. - razgradnja grape juice - sok od grožđa yeast, n. - kvasac conversion, n. - pretvaranje acetic acid - octena kiselina participate, v. - sudjelovati butyric acid - maslačna kiselina proliferate, v. - razmnožavati se, množiti se putem proliferacije EXERCISES A. 1. Underline all the Past Simple forms. 2. Underline all the Future Tense forms. 3. Underline all the Passive forms. 4. Underline all the Participles. B. Write at least 10 questions to cover the text. C. Make a list of all the acids you know in English. You may consult your dictionaries.




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Additional Reading

MICROBIOLOGY

Turning over a new leaf A bacterium without cell walls could prevent disease in cabbages and other crops, writes Bernard Dixon. It is no longer fashionable, or even permissible, for scientists to spend time simply thinking of or studying natural phenomena for any other reason than to develop a saleable product. More is the pity - as a paper published this month in Letters in Applied Microbiology shows. Written by microbiologists, it establishes that bacteria deprived of their cell wall can live in close association with Chinese cabbage cells and thereby protect the plant against disease. The work has considerable practical possibilities. Yet it was initiated by the researchers' late colleague Alan Paton, as a result of observations made while peering for hours down a simple, old-fashioned microscope. The Aberdeen research is based on varieties of bacteria known as L-forms. Bacteria of this sort have lost, either permanently or temporarily, the ability to synthesise the materials that constitute their cell walls. They are bounded only by the delicate membrane that normally lies under the rigid wall. Most bacteria can be turned into unstable L-forms by treating them with penicillin or lysozyme (a natural antiseptic in tears and other secretions). Some of them can be stabilised in that state. Many L-forms also change their appearance as they go through a complex life cycle, which includes tiny granular forms that pass like viruses through very fine filters. Studying potato, carrot and turnip cells from plants infected by bacterial soft-rot diseases, Paton noticed some of the cells were densely packed with bacteria that had caused the disease, but other harmless ones too. Further studies suggested that L-form granules could have entered through apertures denied to much larger, "normal" bacteria. by injecting ordinary bacteria together with penicillin or lysozyme into plant tissues, the Aberdeen microbiologists have since created associations between a wide variety of different bacteria and plants. The fact that the bacteria in such partnerships continue to show the biochemical activities they conducted when living alone suggests that one potential practical use of these associations might be to enhance the nutritional value of crops. Other new characteristics, such as drought and cold resistance, might be introduced into crops too. The other putative range of applications is resistance to the fungi, viruses and bacteria that cause diseases. In theory there are several ways in which an L-form, living in close association with a plant, might protect it against infection. One would be simply by being there, barring the way to invasion by a harmful microbe. More actively, an L-form could produce an antibiotic that destroys the invader. This month's report by Anne Glover and her colleagues provides evidence that L-forms can indeed protect plants against disease-causing bacteria. Their experiments were in two parts. First, they prepared L-forms of the bacterium Pseudomonas syringiae and added them to germinating Chinese cabbage




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seeds. They grew the seedlings, and removed any surface bacteria and confirmed the presence of the bacterium inside the plant. To determine whether the Chinese cabbage could now resist a potentially serious infection, they used Xanthomonas campestris, a bacterium responsible for spot disease of peppers and other infections. To facilitate infection, they damaged the leaves of the seedlings and then applied X. campestris. The result was striking. Six days later, plants carrying the L-forms were healthy and showed no sign of disease, while the plants that had not been augmented by the L-forms, were in a bad way. The leaves infected by X. campestris were dead, and the others were wilting. Experiments with the original Ps. syringae showed it failed to protect Chinese cabbage in the same way; only the L-form worked. It's not yet clear how the L-forms safeguard the plant cells against invasion. However, the effect seems not to be one of simple physical exclusion, because Ps. syringae with its cell wall intact does not work. What seems to happen is that the plant responds to the L-form, with which it can co-exist, in such a way as to repel more threatening invaders. GLOSSARY - MICROBIOLOGY phenomenon, n. pl: phenomena - pojava; fenomen deprived, adj. - lišen, bez cell wall, n. - stanična stijenka late, adj. - pokojni peer, v. - zuriti bounded, adj. - ograničen delicate, adj. - osjetljiv; tanak tiny, adj. - sićušan fine, adj. - sitan, tanak rigid, adj. - čvrst, krut treat, v. - tretirati; liječiti turnip, n. - bijela repa densely, adv. - gusto; zgusnuto aperture, n. - otvor association, n. - nakupina; skupina drought, n. - suša; suhoća putative, adj. - takozvani, navodan; tobožnji disease-causing bacteria - bakterije koje uzrokuju bolest fungus, n. pl. fungi - gljivica virus, n. pl: viruses - virus seedling, n. - presadnica augment, v. - povećati, uvećati wilt, v. - uvenuti repel, v. - odbiti




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EXERCISES A. After you have read and understood the text, read it again trying to find the answers to the questions bellow. Read the questions first. 1. What does a paper published this month in Letters in Applied Microbiology show? 2. Is this an important finding? 3. Who started it? 4. What is the Aberdeen research based on? 5. Which plants did Alan Paton study? 6. What did he find out? 7. What have the Aberdeen microbiologists created since? 8. What is the other putative range of applications? 9. What do Anne Glover and her colleagues report? 10. In how many parts were their experiments done? Describe them. 11. What was the result of their experiment? Describe it. 12. What is the conclusion of the paper? 13. What is your own conclusion after reading this text? 14. Can you find a hint of criticism while reading the paper? 15. Do you agree with it and why? State your point. B. Find at least two sentences with gerund forms. C. Find at least two sentences with present participles. D. Find at least two sentences with past participles. E. Find at least two sentences in passive form.




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OXYGEN, OXIDATION, ANTIOXIDANTS

Oxygen can be beneficial - or it can be harmful. We all need oxygen to live, to grow, to be energetic. Oxygen starvation prevents our healthy cells from functioning properly. Although essential to life, oxygen can also be destructive through oxidation. Oxidation is the process of oxygen combining with other compounds in our bodies. An example of undesirable oxidation is the interaction of oxygen with components of the cell membrane called lipids. This oxidation reaction results in the breakdown of body cells. The oxidation of lipids also creates peroxides which are damaging to proteins. Lipid peroxidation and damage to crucial proteins causes cells to deteriorate during the ageing process. An iron fence will corrode, creating iron-oxide when exposed to the oxygen in air. Just as a good coat of paint protects the iron fence from oxidation, so will certain nutrients protect our body cells from oxidation. Our bodies are composed of billions of cells and the health of these cells is directly related to our health. Vitamins A, C, E and Selenium are nutrients which keep our body cells functioning properly by limiting oxidation damage.

VITAMIN A Beta-Carotene, an important antioxidant in our food, is converted to vitamin A in the body. It protects body fat and lipid membranes against oxidation by trapping potentially dangerous oxygen molecules. It also increases the ability of cells to prevent foreign substances from penetrating them. Experiments have indicated that a lack of vitamin A made body cells more vulnerable to certain harmful conditions while increased amounts of vitamin A made them more resistant.

VITAMIN C This oxidant vitamin was found to deduce the damage to proteins from peroxides. Generously supplied, it protects the liver from damaging substances.

VITAMIN E Vitamin E has long been recognized as an important antioxidant and has been used clinically in a variety of oxygen-related conditions. Like other antioxidants, it works by uniting with oxygen to prevent the oxygen from being converted to harmful peroxides. By inhibiting oxidative damage to cell membranes, the integrity of our body cells is maintained.

SELENIUM

Researchers have shown that people living in regions where Selenium is found in water and plants have fewer incidences of certain degenerative conditions than people living in Selenium deficient areas. Selenium is known to be an essential component of an enzyme (Glutathione Peroxidase) that helps to prevent oxidation damage to cells.




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GLOSSARY - OXYGEN - OXIDATION - ANTIOXIDANTS beneficial,adj. - koristan harmful, adj. - štetan, škodljiv starvation, n. - glad, nedostatak oxidation, n. - oksidacija undesirable, adj. - neželjeni, loš breakdown, n. - razgradnja, raspadanje crucial, adj. - bitni, važni, krucijalni fence, n. - ograda expose, v. - izložiti paint, n. - boja damage, n. - šteta convert, v. - pretvoriti increase, v. - povećati ability, n. - sposobnost trap, v. - uhvatiti, uloviti, hvatati lack, n. - nedostatak vulnerable, adj. - ranjiv, osjetljiv reduce, v. - reducirati, smanjiti damage, n. - šteta liver, n. - jetra recognize, v. - prepoznati, priznati, prihvatiti unite, v. - ujediniti se, sjediniti se, spojiti se inhibit, v. - spriječiti, onemogućiti maintain, v. - održavati, održati research, n. - znanstveno istraživanje incidence, n. - pojavljivanje, rasprostranjenost degenerative condition - degenerativna stanja deficient, adj. - manjkav component, n. - sastavni dio tissue, n. - tkivo water-soluble, adj. - topljiv u vodi oil-soluble, adj. - topljiv u ulju level, n. - razina, nivo, depletion, n. - iscrpljenje, ispražnjenje adverse, adj. - suprotan, protivan, štetan, nepovoljan EXERCISES A. 1.Name the beneficial and harmful effects of oxygen. 2. Say which nutrients are essential for our body and why.




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B. Translate into Croatian: These four nutrients work together to help protect the body's tissues against oxidation damage. Vitamin C works in water-soluble regions of the cell, while Vitamin E works in oil-soluble regions of the cell. Vitamin C levels in the blood decrease with the depletion of Vitamin A. Vitamin E works alongside Vitamin A by protecting Vitamin A from being destroyed by oxygen. Vitamin E also supports Selenium; they work together in avoiding adverse oxidations. Selenium neutralizes peroxides while vitamin E protects fats from being destroyed by oxygen.




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Revision Test ENERGY FOR LIFE

A. Each of the underlined words below has several meanings. Use the context

to help you decide which of the meanings is appropriate in each case. Read each text through first, then circle the letter in front of the right answer. Example: When plants make sugar they convert light energy into chemical energy. a) take someone's property and use it b) cause a person to change his opinion and beliefs c) change from one state, use or purpose into another d) change from one type of money to another Right answer: c

1.The various processes carried out by the body, such as movement, growth and reproduction, all require the expenditure of energy.

a) treatments of film for developing b) series of actions leading to a particular result c) projecting pieces of bone d) particular systems or treatments of materials used 2. During daylight hours, green leaves absorb carbon dioxide and water and

release oxygen. a) set free b) press (of a handle) c) allow to be printed d) give up (a property or a right) 3. One group of digestive enzymes breaks down starchy foods into sugars such as glucose. a) fails to function b) collapses c) separates into simple substances d) destroys 4. The carbon cycle refers to the movement of carbon compounds from the bodies of plants and animals into the air and back again. a) a complete series of events that recur again and again b) a long period of time c) a form of transport with two wheels d) a group of songs, poems, etc., connected with a theme 5. Just as wood when burned gives off energy in the form of heat and light, so food gives off energy when it is burned, or oxidized, in the cells.




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a) small rooms in prison b) groups of people in a secret political organization c) pieces of apparatus for making a current of electricity d) individual units of living matter B. The following passage describes the two important processes of

photosynthesis and respiration. Read through it carefully and fill in the gaps. Choose the correct word from the alternatives given in the margin. All life on earth exists ................. two chemical so that / because of processes called photosynthesis and respiration. Through photosynthesis, green plants make carbohydrates ................ carbon dioxide (in the air) to / from and water (in the soil), using ....... energy of an / the sunlight absorbed ........ the chlorophyll in their by / of leaves. Oxygen gas is a by-product of the process ...... is released into the atmosphere. and / but Through respiration, both plant and animal cells take up oxygen and use it ........ turn the sugar to / for in food into energy. The by-products of respiration, water and carbon dioxide, are returned to the atmosphere to ......... used once again in be / have photosynthesis. ........ cycle is endlessly repeated. A / The

C. Now translate the previous passage into Croatian. D. Read the short text below. It gives a short factual description of the process

of photosynthesis. Notice the underlined verbs. During photosynthesis plants make sugars such as glucose. To do this, the

energy of light is absorbed by the chlorophyll and is used to combine oxygen and water. Oxygen is released as a by-product and diffuses out of the plant into the atmosphere.

1. What are the verbal forms used in this description? Say why. E. The following sentences are all factual descriptions of biological structures. Put the verbs in brackets into the correct form. 1. A cell .................... of a nucleus and cytoplasm. (consist) 2. The nucleus of a cell ............. by a jelly-like substance. (surround) 3. The jelly-like substance ............... cytoplasm. (call) 4. The thin skin, which ............ the cytoplasm and (enclose( nucleus of a cell, is known as the cell membrane. 5. The cell membrane ............. certain chemicals to (allow) pass in and out of the cell. 6. Other chemicals, however, ............ from passing (prevent)




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through the membrane. 7. The body .............. with skin and hair. (cover) 8. A membrane is a sheet of tissue which covers or ................. a surface. (line) F. Translate these sentences into Croatian. G. Read the following passage and while reading think about the answers to these questions. 1. How can respiration be defined? 2. What are the raw materials of respiration? 3. What are the products of respiration? 4. What two forms of respiration are described? _________________________ In modern biology, respiration can be defined as: the processes which lead to,

and include, the chemical breakdown of materials to provide energy for life. These processes occur inside the living cells of every type of organism.

The energy for life is released during respiration from substances known as food. There are many different foods and they are taken into the body in many different ways, but in the majority of organisms foods are converted into the sugar, glucose, before they are used as a source of energy.

In most organisms, energy is released by a process called aerobic respiration, which requires a continuous supply of oxygen molecules obtained from the air or water surrounding the organism. In certain circumstances, however, energy can be released without the use of oxygen molecules. This is known as anaerobic respiration.

The aerobic respiration of glucose is usually summarized by the following chemical equation:

C6H12O6 + 6O2 ------------------->6CO2 + 2898 kJ of energy Aerobic respiration releases all the energy within each glucose molecule; that

is, it produces the same amount of energy that is released when glucose is burnt in oxygen gas. The chemical equation above gives the false impression that respiration involves only one chemical reaction because it shows only the raw materials and end products of respiration. The whole process involves some fifty separate reactions, each catalyzed by a different enzyme. The result is a controlled release of energy which is far more useful to the organism than a sudden explosive burst of energy.

ANAEROBIC RESPIRATION

It differs from aerobic respiration in three important ways. First, anaerobic

reactions break down glucose in the absence of oxygen molecules. Second, anaerobic reactions do not completely break down glucose into carbon dioxide and water, but into substances such as lactic acid or alcohol. Third,




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anaerobic respiration releases far less energy than aerobic respiration, because glucose is not completely broken down. Organisms which respire anaerobically are called anaerobes.

Certain bacteria are complete anaerobes. They live permanently in conditions where no oxygen exists. Certain other micro-organisms, such as yeast, obtain most of their energy by anaerobic respiration, but can also respire aerobically in the presence of oxygen.

Give a title to the passage. Choose the best alternative a) Aerobic and Anaerobic Respiration b) energy for Life through Respiration c) The Need for Oxygen H. Say if the following statements are TRUE or FALSE. Put a T in front of the true statements and an F in front of the false ones. Correct the false statements. 1, Respiration involves a single, simple chemical reaction. 2. Organisms which respire anaerobically can live in conditions where no molecular oxygen exists. 3. Enzymes speed up the chemical reactions of respiration and this results in the release of violent bursts of energy. 4. During aerobic respiration, glucose is oxydized completely to produce carbon dioxide and water. 5. Anaerobic respiration releases far more energy than aerobic respiration. 6. Yeast can respire both aerobically and anaerobically.




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DIGESTION AND ABSORPTION

Digestion is both physical and chemical; the chemical process involves the breakdown of larger molecules into smaller ones, while the physical process involves the breakdown of large food particles into smaller ones. Foodstuffs are mainly complicated, insoluble substances that must be converted into simpler, soluble, more active ones before they can be used by the body. Not all nutrients need digesting, however, for there are some such as water and simple sugars (e.g. glucose) and many vitamins and mineral salts which do not need to be broken down. Whether or not nutrients need to be broken down by digestion they cannot be utilized by the body until they have passed into the bloodstream in a process which is known as absorption. Once in the bloodstream nutrients are distributed to all the cells of the body where they sustain the complex processes of metabolism.

THE ROLE OF ENZYMES IN DIGESTION The chemical processes involved in digestion are brought about by enzymes. The chemical breakdown of food molecules, which in the absence of enzymes would be very slow, is speeded up so that digestion is completed in a matter of hours. Thus, in three or four hours a remarkable change in the nature of the food has occurred. Substances such as starch, which may contain as many as 150,000 atoms in a single molecule, have been converted into molecules containing only 24 atoms (simple sugars such as glucose). An average protein molecule is split up into about 500 amino acid molecules during digestion. These two examples perhaps make clearer the magnitude of the chemical task performed by the enzymes of the digestive system. Each stage of digestion involves hydrolysis and is catalyzed by a hydrolysing enzyme or hydrolase. The hydrolysis can be represented as

AB + H2O --------------->AOH + BH The equation shows how water is involved in splitting up a molecule AB into two smaller molecules AOH and BH. In some instances, e.g. sucrose, a single step involving the breakdown of a molecule into two parts is sufficient to produce a small soluble molecule that can be absorbed. In other instances, e.g. proteins, a very large number of hydrolytic steps is required before breakdown is complete. When food is eaten, the size of the individual pieces is reduced and saliva is secreted by the salivary glands. Saliva becomes well mixed with food during mastication, lubricating it and so making it easier to swallow. Saliva is a dilute aqueous solution having solid content of only about 1%. Its main constituent is a slimy substance called mucin which assists lubrication. It also contains the enzyme salivary amylase, and various inorganic salts, the most abundant being sodium chloride which furnishes chloride ions that activate the enzyme. The initial hydrolysis of cooked starchy food is catalyzed by salivary amylase in the mouth, and this catalytic action is continued as the food moves down the oesophagus and into the stomach. The enzyme soon becomes inactivated in the stomach, however, because it cannot tolerate a strongly acid environment.




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Food is carried down the oesophagus by gentle muscular action called peristalsis. The muscles contract, producing a peristaltic wave and this moves down the oesophagus, carrying the food with it.

DIGESTION IN THE STOMACH The stomach may be regarded as a reservoir in which food is prepared for the main stage of digestion in the small intestine. This does not mean that no digestion takes place there, for the cells in the lining of the stomach produce a fluid called gastric juice. The two essential constituents of this (gastric juice) dilute aqueous solution are its enzymes and its acid content. The main enzyme is pepsin which is secreted as the inactive pepsinogen and which becomes activated when it comes into contact with the hydrochloric acid constituent of the gastric juice. Some twenty minutes after starting to eat a meal, vigorous muscular movements begin in the lower region of the stomach. Muscular contraction produces an inward pressure and this moves down the stomach wall as a peristaltic wave, so moving food through the stomach and causing it to become mixed with the gastric juice. In this way the acidity of the semi-fluid food mixture called chyme increases, until the endopeptidase pepsin is able to catalyze the conversion of part of the protein into slightly simpler molecules called peptones. The other enzyme in the gastric juice is rennin, which also acts in an acid medium and brings about the coagulation or clotting of milk. The acidity of the gastric juice also causes some bacteria, which enter with the food, to be killed. A copious flow of gastric juice is necessary during a meal and its production is stimulated both by psychological and chemical means. Certain foodstuffs act as chemical stimulants to secretion. Meat extractives, for instance, which are dissolved out of meat when it is put in boiling water, are particularly potent in this respect. Soups and meat dishes in which the extractives have been preserved are therefore valuable aids to digestion in the stomach.

DIGESTION IN THE SMALL INTESTINE

The main stage of digestion occurs during the passage of chyme through the long, small intestine. As soon as food enters the duodenum, digestive juices pour forth. There are three sources: the liver secretes bile which is then stored by the gall bladder, and the pancreas secretes pancreatic juice - these two secretions enter the small intestine; the third is produced in the lining of the small intestine and is called the intestinal juice. They are all produced at the same time and as they are alkaline they neutralize the acidity of the chyme. Under these conditions the enzymes of the three secretions are able to exert their catalytic influence. The pancreatic juice contains enzymes which enable it to help in the digestion of the three main types of nutrient. The endopeptidases, trypsin and chymotrypsin among others, carry on the degradation of proteins begun by pepsin in the stomach; they complete the breakdown of proteins into peptones. Pancreatic amylase is another enzyme present in the pancreatic juice; its capacity for catalyzing the hydrolysis of large amounts of starch and




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converting it into maltose should be discussed separately. Pancreatic lipase brings about the partial hydrolysis of some fat molecules converting them into simpler substances which can be absorbed. The bile has no enzyme action, but contains bile salts which convert fats (which are liquefied by the warmth of the stomach) into a fine emulsion of tiny oil droplets which may be then acted upon by the lipase of the pancreatic juice. The intestinal juice contains a number of enzymes which break down the double sugars into simple sugars that can be absorbed. A group of exopeptidases, called erepsin, continue the breakdown of proteins begun by the endopeptidases pepsin, trypsin and chymotrypsin. They attack the ends of the chain-like peptone molecules until they are broken down into small units called dipeptides containing only two amino acids. Finally, another group of enzymes called dipeptidases break down the dipeptides into free amino acids which can be absorbed.

ABSORPTION IN THE SMALL INTESTINE

The digestive process is almost complete after the food material has been in the small intestine for some time. The proteins have been converted by stages into amino acids; all carbohydrates, except cellulose, have been broken down into simple, soluble sugars, while fats have been emulsified and partly split into simpler substances called fatty acids and glycerol. However, all these nutrients can be utilized by the body only after they have passed into the bloodstream, by the process of absorption. The absorptive process in the small intestine is not a simple one, and it involves both diffusion and active transport. The mechanism of diffusion is explained in terms of osmotic forces, which depend upon a concentration gradient across the membrane. Diffusion of dissolved substances takes place so as to reduce the concentration gradient, that is from the more concentrated to the less concentrated solution, provided that the membrane is permeable to the dissolved materials. Diffusion of soluble nutrients from the small intestine to the bloodstream depends therefore on the concentration gradient and the permeability of the membrane. The mechanism whereby nutrients are absorbed against the concentration gradient is known as active transport. The products of protein and carbohydrate digestion, namely amino acids and simple sugars, are absorbed by diffusion and active transport, but the mechanism of fat absorption is a subject of some controversy. It seems safe to say that some fat is absorbed undigested in an emulsified form and that the minute fat droplets pass directly through pores in the intestinal wall; also that some fat is absorbed in a partially hydrolized state and some as fatty acids and glycerol.




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THE LARGE INTESTINE

About four hours after a meal has been eaten any food that has not been digested and absorbed in the small intestine, passes into the large intestine. No new enzymes are produced by the body during this stage but the large intestine is a rich source of bacteria. These may attack undigested substances such as cellulose with their own enzymes and partially break them down. In addition, vitamin K and certain vitamins of the B group are synthesized, i.e. built up by the bacteria. The main function of the large intestine is to remove water from the fluid mass; this process continues as the fluid passes along, so that by the time it reaches the end of the tube it is in a semi-solid form known as faeces. In a day, between 100 and 200 grams of moist faeces may be produced containing undigested food material, residues from digestive juices, large numbers of both living and dead bacteria, and water. After having been in the large intestine for about twenty hours these materials are passed out of the body.

TRANSPORT IN THE BODY Food, after digestion and absorption, provides nutrients that are the raw materials of body metabolism. But this process is not complete without an efficient transport system capable of carrying nutrients to the cells that require them. The constant circulation of blood through the body system enables these nutrients to be transported to where they are needed. Blood, which is four-fifth water, contains many substances, such as nutrients and hormones, in solution. Other substances, such as the red blood corpuscles which transport oxygen are present as cells in the blood and are carried round with it in suspension. The heart pumps blood through the arteries to the capillaries. There, nutrients and oxygen from the blood diffuse into the blood. Blood carrying the waste material passes into a network of veins, carbon dioxide is removed by the lungs, while soluble substances are removed by the kidneys. GLOSSARY - DIGESTION AND ABSORPTION digestion, n. - probava foodstuffs, n. - hrana utilize, v. - koristiti bloodstream, n. - krvotok sustain, v. - održavati; hraniti absence, n. - odsutnost magnitude, n. - velićina, važnost task, n. - dužnost; uloga require, v. - trebati, tražiti. zahtijevati saliva, n. - slina secrete, v. - izlučivati




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salivary gland, n. - pljuvačna žlijezda mastication, n. - žvakanje lubricate, v. - podmazati lubrication, n. - podmazivanje lubricant, n. - mazivo swallow, v. - gutati stomach, n. - želudac dilute, v. - razrijediti slimy, adj. - sluzav abundant, adj. - obilan furnish, v. - osigurati, opskrbiti muscle, n. - mišić constituent, n. - sastavni dio (bitan) aqueous, adj. - voden, vodenast inactive, adj. - neaktivan gastric juice - želučani sok vigorous, adj. - snažan inward, adj. - unutarnji clotting, n. - grušanje copious, adj. - obilan small intestine - tanko crijevo bile, n. - žuč gall bladder - žučni mjehur lining, n. - sluznica exert pressure - vršiti pritisak droplet, n. - kapljica act (up)on - djelovati na permeable, adj. - propusan permeability, n. - propusnost faeces, n.pl. - fekalije corpuscle, n. - tjelešce medium, n. pl: media - sredstvo, medij oesophagus, n. pl: oesophagi - jednjak EXERCISES A. 1. Number the paragraphs. 2. Give a key word or a key sentence for each paragraph.




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B. 1. Fill in the blanks. Digestion is both _________________ and __________________ . The _____________ process involves the ________________ of larger _______________ into __________ ones, while the _______________ process ______________ the breakdown of large ________________ _________________ into smaller ones. When food is eaten, the _________ of individual pieces is __________ and saliva is _______________ by the _______________ glands. ____________ becomes well mixed with _____________ during _______________, ________________ it and so making it ______________ to _________________ . C. Give definitions for: a) foodstuffs - b) absorption - c) enzymes - d) saliva - e) mucin - f) gastric juice - g) rennin - h) pancreatic juice - i) intestinal juice - j) pancreatic amylase - k) faeces - D. Make a table of classification for: a) digestion in the small intestine b) digestion in the large intestine E. Transport in the body 1. Find all the sentences in the passive form and copy them in the space below. 2. Translate the passage.




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4. Name the main phases of digestion. 5. Describe the role of enzymes in digestion.




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DETERMINATION OF SUGARS

TOTAL SUGARS The phenol/sulphuric method can be recommended for sugar estimation since it is sensitive, rapid and accurate. It estimates all sugars whether reducing, non-reducing, substituted or in polymeric form. In potatoes after storage, sucrose, fructose, and glucose, together constitute the majority of sugars. Put 2 cm3 of a sugar solution containing between 0.01 and 0.1 mg cm-3 of sugar into a test tube or colorimeter tube and add 1 cm3 of an aqueous solution of phenol. Add 5 cm3 of concentrated sulphuric acid rapidly, directing the stream of acid against the solution surface in order to obtain good mixing. Let the tubes stand for 10 minutes, then shake them and place them in a water bath for 10 to 20 minutes at 25 to 30oC before taking the readings. A colour filter should be chosen which transmits the wavelength that is most strongly absorbed by the solution. This will be around 4.80 10-7 m. The colour is stable for several hours and readings may be made later if necessary. A standard curve may be prepared for solutions containing 0.02, 0.04 and 0.1 mg cm-3 sugar. If no colorimeter is available then the solutions of unknown concentration may be compared visually with those of unknown concentrations. For determination of the total sugars, a standard curve for the phenol/sulphuric acid reaction may be prepared from a mixture containing equal proportions of glucose, fructose, and sucrose over a total concentration range of 0.01 to 1 mg cm-3. EXERCISES A. Paragraph 1. Translate precisely consulting your dictionaries: sugar estimation - sensitive - rapid - accurate - (non-) reducing - substituted - B. Translate Paragraph 1: C. Why can the phenol/sulphuric method be recommended? Find the answer in the text.




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D. Translate the rest of the passage. E. Describe an experiment that you have done yourself. F. Underline the verbal forms in Paragraph 2 and discuss them. G. Underline all the modal verbs in Paragraphs 3 and 4.




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VITAMINS AND THEIR FUNCTIONS More than 30 compounds are known to have the properties of vitamins. They are needed in very small amounts. Vitamins are raw materials for the production of a large number of coenzymes, substances vitally important to the function of many enzymes. Consequently, the long absence of vitamins from a cell impairs metabolic processes and produces unsteady or diseased states. In this connection, careful distinction should be made between the biological and clinical effects of a deficiency. Most, and possibly all cells of an organism, require most or all vitamins. If a vitamin deficiency exists, some metabolic process in cells will be impaired. This is a biological effect. The B vitamin riboflavin, for example, is a precursor of a coenzyme that functions during respiration. If riboflavin is in deficient supply, respiratory reactions in cells will be affected. Superimposed on such biological effects are clinical ones. They become evident when the cells of given tissues or organs are more sensitive to a deficiency than other cells. Such sensitive cells will then exhibit symptoms of disease sooner or more pronouncedly than others: For example, riboflavin deficiency in mammals has long been known to lead to loss of hair, to growth failure, and to eye disorders. By themselves, clinical data alone would imply that riboflavin is required specifically in hair, bones and eyes. Actually, however, clinical results represent only the large-scale secondary consequences of the deeper biological effects of deficiency, which influence most or all cells. EXERCISES A. 1. Consulting your dictionaries complete the glossary with Croatian equivalents for the words listed. GLOSSARY - VITAMINS AND THEIR FUNCTIONS consequently, adv. - unsteady - deficiency - affected - given (tissues) - fail - failure - large - scale - impair - distinction - superimposed - pronouncedly - imply -




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B. SYNONYMS impair - damage, harm affect - influence consequence - effects, after-effect consequently - therefore, accordingly, hence failure - omission of performance of and action or task pronounced - definite, decided distinction - difference imply - suggest, indicate, point secondary - subordinate, inferior impose - use, exploit super - highly, exceptionally, very C. ANTONYMS Now give the antonyms (opposite meanings) for the words listed in exercise B. D. Identify the following: 1. produce coenzymes - 2. absence impairs metabolic processes - 3. vitamin deficiency, metabolic process impaired - 4. the cells of given tissues more sensitive to a deficiency than others - E. FACTUAL QUESTIONS 1. Why are vitamins raw materials? 2. What is the consequence of a prolonged absence of vitamins from cells? 3. Explain the difference between biological and clinical effects of vitamin deficiency in a cell. 4. Take the example of riboflavin and explain the difference between biological and clinical effects.




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F. Write the adjective and then the adverb of the following nouns: Example: science scientific scientifically NOUN ADJECTIVE ADVERB problem curiosity truth experiment hypothesis instrument universe G. Translate the passage into Croatian.




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VITAMINS Until about 70 years ago it was supposed that a diet containing adequate amounts of protein, carbohydrate, fat, mineral elements and water would be sufficient for the maintenance of health. It was found, however, that animals fed on an artificial diet containing only these nutrients did not thrive and it is now known that small quantities of certain other nutrients called vitamins are required in addition. Vitamins are organic compounds found in small amounts in many foods; their presence in the diet is essential because, with a few exceptions, the body is unable to synthesize them from other nutrients. In the case of most vitamins a deficiency will cause a check in the growth of children and this is usually aggravated by a loss of appetite. Various diseases called deficiency diseases, are also associated with shortages of specific vitamins. Deficiency diseases have been the cause of much suffering and death for many centuries but today they can be prevented and cured by ensuring that the diet contains a sufficient quantity and variety of vitamins. Most vitamins are very complex chemically; they do not belong to one chemical family but are all quite different from each other. However, the structures of all of them are known and, with one exception, they can be prepared synthetically. Before their structures were determined the vitamins were designated by letters as vitamin A, vitamin B and so on. They are now known by names which give some indication of their chemical structure and in general these names are used in preference to the letters. Foods contain only very small quantities of vitamins, but these small amounts carry out some of the most important tasks in the body. Members of the B group of vitamins form part of several coenzyme molecules which are absolutely necessary for the maintenance of good health. The other vitamins are essential, though in some cases their exact job in the chemistry of the body is not known. Only small amounts of vitamins are needed by the body and the minute quantities present in foods are usually sufficient for man's needs. They are, however, distributed among many types of food, and to ensure that all the vitamins are represented in the diet it is important that a variety of different foods is eaten. The vitamin content of a food can vary quite considerably. This is especially so with fruit and vegetables, where the vitamin content depends, among other things, on the freshness and variety, and climatic conditions during its growth. It is so important that sufficient quantities of vitamins are consumed that in some cases extra vitamins are added to food. Examples have already been encountered in connection with flour, to which the vitamins thiamine and nicotinic acid are added to replace what has been lost during milling, and margarine to which vitamins A and D are added. In these cases synthetic vitamins are used and this demonstrates how useful a knowledge of their structures is because otherwise synthesis would be impossible. All the known vitamins have now been isolated in a pure form and international units can be precisely defined in terms of the weight of pure vitamin. Vitamin C, for example, has been prepared in crystalline form and the international unit defined as 0.05 mg of the pure vitamin.




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VITAMINS NAME MAIN SOURCES FUNCTION IN THE BODY

AND THE EFFECT OF SHORTAGE Vit. A Green vegetables, milk Necessary for healthy skin dairy products, margarine, and for normal growth and fish liver oil development. Deficiency will slow down growth and may lead to disorders of the skin, lowered resistance to infection and disturbances of vision such as night blindness. Vit. B Bread and flour, meat, Function as co-enzymes in milk, potatoes, yeast many of the reactions extracts. Involved in making use of food. Shortage causes loss of appetite,

Slows growth and development and impairs general health. Severe deficiency may lead to a deficiency disease such as pellagra or beriberi. Vit. C Green vegetables, fruits Necessary for the proper formation potatoes, black current of teeth, bones and blood syrup, rosehip syrup vessels.

Shortage causes a check in the growth of children and if prolonged may lead to the disease scurvy.

Vit. D Margarine, butter milk, Necessary for the formation fish liver oils, fat fish of strong bones and teeth. A shortage may cause rickets and possibly dental decay. GLOSSARY vitamin, n. - vitamin diet, n. - hrana ishrana adequate, adj. - odgovarajući sufficient, adj. - dovoljan maintenance, n. - održavanje health, n. - zdravlje




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nutrient, n. - hranjiva tvar nutrient, adj. - hranjiv thrive, v.(throve, thriven)- napredovati deficiency, n. - nedostatak, pomanjkanje check, n. - zastoj check in the growth - zastoj u rastu, razvoju aggravate, v. - pogoršati, otežati loss, n. - gubitak disease, n. - bolest death, n. - smrt ensure, v. - osigurati designate, v. - odrediti, označiti preference, n. - prednost task, n. - zadatak distribute, v. - razdijeliti flour, n. - brašno milling, n. - meljava brašna margarine, n. - margarin demonstrate, v. - pokazati, dokazati source, n. - izvor dairy products, n. - mliječni proizvodi liver, n. - jetra shortage, n. - manjak, nestašica, nedostatak slow down, v. - usporiti disorder, n. - poremećaj vision, n. - vid yeast, n. - kvasac impairment, n. - oštećenje severe, adj. - ozbiljan pellagra, n. - pelagra beriberi, n. - beriberi black currant, n. - crni ribiz rosehip, n. - šipak blood vessel, n. - krvna žila scurvy, n. - skorbut rickets, n. - rahitis EXERCISES A. Say whether these sentences are true or false. Use the table to Justify your answers. ___1. Milk is poor in vitamins A and B ___2. An adequate supply of vitamin C can be obtained from milk. ___3. Fresh fruit contains a considerable amount of vitamin C. ___4. Shortage of vitamin A causes the disease scurvy. ___5. Vitamin C deficiency causes a check in the growth of children. ___6. Fish liver oil is rich in vitamin A. ___7. The B vitamins function as co-enzymes.




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___8. An insufficient amount of vitamin D may cause rickets. B. Complete the sentences using the following words: skin, deficiency, severe, necessary, shortage. 1. Vitamin A is necessary for healthy ............... . 2. A ................ in vitamin A causes bad teeth. 3. Grow strong and healthy. ............... . 4. The state of having less than is needed. ................ . 5. That which is contained in something ................ .




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ASCORBIC ACID

Ascorbic acid, or vitamin C, is a white water-soluble solid of formula C6H8O6. In spite of the name ascorbic acid the molecule does not contain a free carboxyl group. It is really a lactone formed from the free acid by loss of water between the carboxyl group on one carbon atom and the hydroxyl group on another. Lactones behave very like as acids and for many purposes can be regarded as such. Ascorbic acid has the sharp taste optically active and is dextrorotatory. Ascorbic acid is a good reducing agent and consequently it is easily oxidized. The oxidation product dehydroascorbic acid is easily reconverted into ascorbic acid by mild reducing agents and because this reduction can be accomplished by the body it is as active as the ascorbic acid and only small amounts are present in foods. Of all the vitamins, ascorbic acid is the most easily destroyed by oxidation, and in extracts, juices, and foods with cut surfaces, it may be oxidized by exposure to air. The oxidation is catalysed by oxidases which are contained within the cells of foodstuffs and are set free on cutting, chopping or crushing. The rate of oxidation is greatly accelerated by heat, by alkalis and especially by traces of copper which catalyses the oxidation. The rate of oxidation is diminished in a weak acid solution and by storage in the cold. Ascorbic acid occurs mainly in vegetable foods. Fruits are usually good sources, but many popular eating apples, pears and plums supply negligible amounts. Green vegetables and potatoes are the most important sources of ascorbic acid in our diet. GLOSSARY - ASCORBIC ACID reducing agent, n. - redukcijski agens ascorbic acid, n. - askorbinska kiselina lactone, n. - lakton dextrorotatory, adj. - desnorotirajući consequently, adv. - zbog toga, dosljedno tome convert, v. - pretvoriti accomplish, v. - postići exposure, n. - izloženost catalyse, v. - katalizirati foodstuffs, n. - prehrambeni proizvodi cutting, n. - rezanje chopping, n. - sjeckanje crushing, n. - drobljenje trace, n. - trag diminish, v. - umanjiti




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EXERCISES A. Read the text carefully and suggest a suitable heading for each paragraph. Paragraph 1. ............................... Paragraph 2. ............................... Paragraph 3. ............................... Paragraph 4. ............................... B. Decide whether the following statements are true or not true according to the text. Correct the false statements. _____1. Vitamin C has all the characteristics of a true acid. _____2. In spite of being a good reducing agent, ascorbic acid is easily oxidized. _____3. Vitamin C is so stable that it is not affected by exposure to air. _____4. The best way of providing the necessary amount of vitamin C is to eat as many apples as possible. _____5. Food articles containing ascorbic acid should be stored in dark and cold places. C. Find the words in paragraphs 2 and 3 similar in meaning to: consider - connect - quantity - inside - decrease - particularly - D. Find opposites in column B for the words in column A. A B ___ 1. major a. unpalatable ___ 2. harmless b. dead ___ 3. palatable c. minor ___ 4. live d. harmful ___ 5. desirable e. insufficient ___ 6. tough f. dormant ___ 7. favourable g. soft ___ 8. active h. unfavourable ___ 9. sufficient i. undesirable E. Before each word in list A write the letter that indicates the meaning




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from list B. 1. consequently a. achieve 2. accomplish b. consider 3. associate with c. change 4. regard d. as a result of 5. stable e. connect 6. accelerate f. not strong 7. diminish g. make smaller 8. weak h. make faster 9. convert i. that does not change easily F. Fill the blank beside each adverb with a related adjective and the blank beside each verb with a related adverb. adequately - ___________________ continue - ___________________ consequently - ___________________ simplify - ___________________ recently - ___________________ generalize - ___________________ steadily - ___________________ regularly - ___________________ understandably - ___________________ G. Choose the correct ending for each sentence: 1. In spite of the name ascorbic acid a) does not contain a free carboxyl group b) contains a free carboxyl group 2. Lactones behave much like a) acids b) dye 3. Ascorbic acid a) is a good reducing agent b) is not easily oxidised 4. Dehydroascorbic acid a) is easily reconverted into ascorbic acid b) cannot be reconverted into ascorbic acid 5. Of all the vitamins ascorbic acid a) is the most easily destroyed by oxidation b) cannot be oxidised by air 6. Ascorbic acid occurs a) mainly in vegetables




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b) mainly in fruits H. Complete the following sentences using: in spite of; regarded as; consequently; accomplish; contained; the rate of; set free; negligible; 1. __________________of oxidation is accelerated by heat. 2. The oxidation is catalyzed by oxidases which are ____________ within the cells of foodstuffs. 3. The oxidases are _________________--on cutting, chopping, etc. 4. _____________of its name ascorbic acid molecule does not contain a free carboxyl group. 5. Lactones can be ________________ as acids. 6. Ascorbic acid is a good reducing agent and _______________ it is easily oxidised. 7. This reduction can be _______________by the body. 8. Fruits supply ascorbic acid in __________________ amounts. I. Translate the following passage into Croatian.

GERMS MAY BLOCK ABSORPTION OF VITAMIN C You've been stricken with the very latest bug. Maybe it's bronchitis or an ear infection. At any rate, you probably feel miserable. What's your next step besides bed rest? You may need extra vitamin C - researchers believe. They have found that endotoxin, a natural product of the bacteria that are torturing you in the first place, blocks the body's absorption of vitamin C. What this means is that the amount of vitamin C that gets to your body tissues could be a lot less than the amount in your diet. So the amount of vitamin C that keeps you running when you're healthy probably isn't enough when you're sick.




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Additional Reading

SUPERNUTRITION For the best (radiant) health, you must boost a good diet with vitamins and minerals. But which ones? How much? What do they do for you? This exhaustive report packs the latest, need-to-know nutritional bulletins. What's the big news in the nutrition field today? It's that many experienced physicians have finally come to recognize that vitamins in relatively high dosages are extremely helpful in maintaining and restoring health. Fifteen years ago, the same physicians said: " Go ahead and take vitamins - if you want to throw your money away!" Nowadays those same physicians routinely advise patients to use a high-potency vitamin-mineral supplement plus large extra amount of C and E. Like thousands of others in this profession, they have changed from a conservative, antivitamin position to a liberal, provitamin one. Large segments of the medical establishment - The American Medical Association (AMA), Food and Drug Administration (FDA), and medical-school faculties generally - continue, however, to more or less disparage the use of nutritional supplements. Judging from recent trends in medical practice and public opinion, the conservatives appear to be losing a great deal of their support. "These anti-vitamin people are antiquated individuals", say most nutritionists and psychiatrists, "Where have they been? Haven't they read the research?" (Dr. Berger's Immune Power Diet). There is no doubt, for example, that vitamins A, C, and E profoundly affect the quality of your immune system. The efficacy of certain vitamins on certain systems is awesome. Vitamin C even causes interferon (a germ-fighting substance) to be produced. Among pro-vitamin physicians, the current approach is to advise a vitamin intake far in excess of the official RDA (Recommended Dietary Allowance). The RDA's are minimal doses, calculated to prevent outright deficiency in the average healthy individual rather than to fully nourish the tissues, so the dosage is considered inadequate. A further problem with the RDA is that there is no such thing as a biochemically average person. Requirements for specific nutrients can vary widely from one individual to another. In the days of the early sailing ships, when scurvy (vitamin C deficiency) was a big problem, some sailors become mildly ill, others severely ill, and still others died. But many remained entirely free of symptoms! say conservatives. In animal studies, researchers found rats that appeared to need forty times the amount of vitamin A required by others and guinea pigs that required at least twenty times the amount of vitamin C needed by their litter-mates. What this means in practical terms is that it is not easy to predict anyone's needs for vitamins and other essential nutrients. Some superhardy individuals seem able to thrive on "inadequate" diets with no vitamin supplementation at all. At the other end of the scale are those people who, because of genetic defects or acquired deficiencies, are unable to function without extremely heavy doses of certain nutrients, such as niacin, vitamin B6 (pyridoxine), and




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folic acid. In between is the great majority, whose needs vary from modest to large and do not conform to any pattern. If you are taking a moderately potent multivitamin, a provitamin health expert would probably tell you that you are getting more of some nutrient than you need, the right amount of others, and not enough of still others. An anti-vitamin physician might comment that you don't need any of these nutrients in tablet form as long as your diet is well balanced. Today, most pro-vitamin physicians and nutritionists believe in supernutrition, in feeding people a better than natural diet. The vitamin dosages being advocated nowadays are much higher than those recommended by nutrition authorities twenty or thirty years ago. The other big news in nutrition is that many new uses have been found for vitamins and other nutrients. Since the essential nutrients (vitamins, minerals, fatty acids, amino acids, and certain other food substances) are generally harmless under toxic levels, nutritional research can be done at the clinical level by experimenting with actual patients. This process is much more rapid than traditional drug research, which requires that a new medication be extensively tested on animals, then on human volunteers, before it is released to the public. Here, in brief, are some of the recent discoveries. Vitamin A to guard against cancer. A few years ago, the National Research Council came out with a report stating that eating a diet low in fat and abundant in fruits and vegetables may reduce the risk of cancer. The key ingredient in fruits and vegetables is beta-carotene, the chemical origin of vitamin A. In a study that examined the eating habits and health histories of over 265,000 people, it was found that those who followed a diet rich in beta-carotene had about half the normal risk of getting cancer. Beta-carotene is the chemical responsible for the yellowish-orange color of such produce as carrots, squash, cantaloupes, and apricots. It is also present in most green leafy vegetables. If you eat these foods regularly - five times a week or more - you probably have sufficient dietary protection against cancer. If not, it might be wise to take a beta-carotene supplement. So called A-complex capsules, which provide both vitamin A and beta-carotene, are now available. Vitamin B6 for mental health. While it has long been known that lack of certain B vitamins - in particular B1, niacin, and B12 (cobalamin) - can cause mental-emotional problems, many researchers have turned their attention to vitamin B6 (pyridoxine) in recent years. B6 is known to be a mood elevator, especially for women who suffer anxiety or depression. Some researchers have found a combination of B6, zinc, and manganese to be helpful in treating certain forms of schizophrenia, and others studying the effects of nutrition on behavior, say that B6, combined with magnesium and C, is important in helping autistic children. Vitamins C and E for the immune system. These two substances, say nutritionists, are invaluable in maintaining health and prolonging longevity. Vitamin C strengthens the body's capacity to fight illness and also raises the level of interferon in the blood. Vitamin E is an antagonist of free radicals,




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unstable chemicals produced when oxygen is used up by the cells. Because free radicals react readily with other chemicals within the cells, they can cause damage to cellular control mechanisms and are believed to be at the root of the aging process. Since vitamin E is a potent antidote to free radicals, some researchers have called it the youth vitamin. So far we have been talking about the standard vitamins with which we are all more or less familiar. Recent research also suggests that other nutrients - fatty acids and amino acids - are extremely important in maintaining health. GLA, the mother's milk fatty acid. Gamma-linolenic acid is the by-product of an essential fatty acid called linoleic. In the normal human body, GLA is manufactured from ordinary linolenic, a substance found in dietary fat and oils. The body then uses GLA to make PGE1, a prostaglandin that may be helpful in inhibiting blood clotting, dilating blood vessels, lowering cholesterol levels, and reducing inflammation. Some people are unable to produce GLA because of disease, stress, aging, a high-fat diet, and excessive use of alcohol, among other reasons. Low levels of GLA may lead to PMS (premenstrual syndrome), eczema, and arthritis. There are only two natural sources of GLA: mother's milk and the oil of the evening primrose, a flower used medicinally by American Indians and exported by the early settlers back to England, where it has been used as an herbal remedy for over two hundred years. it is only recently that the active ingredient in evening primrose oil was found to be GLA. Clinical research has found many uses for evening primrose oil. Canadian endocrinologists have discovered that it produces dramatic improvement in sufferers of PMS. British experiments have shown that evening primrose oil causes significant improvement in many cases of chronic eczema. Another British research group has reported significant improvement in hyperactive children who were given evening primrose oil. One of the most promising uses of GLA appears to be in treating alcoholism. B.E. Leonard, professor of pharmacology at University College, Galway, Ireland, has discovered in animal experiments that alcohol damages the brain cells by interfering with the fat composition of the membranes surrounding the cells. When the oil is administered, says Leonard, most of these damaging effects are reversed. Supplements of evening primrose oil, together with B complex vitamins (especially thiamin) might help some alcoholics. Ian Geln, M.D., a Scottish psychiatrist, administered evening primrose oil to 120 alcoholics in withdrawal and noted that they recovered more quickly and had fewer symptoms (hallucinations, nervousness) than would ordinarily be expected. In informal experiments with primrose, a number of heavy drinkers reported they were no longer able to get very drunk, had less desire for alcohol than before, and experienced fewer hangovers. Evening primrose oil contains forty-five milligrams of GLA per five-hundred-milligram capsule. The usual daily dose for PMS symptoms is six to eight capsules. After two to three months, the dose can be reduced to two capsules. Glutamine, the antialcohol amino acid. This substance was mentioned in 1971 as a promising remedy for alcoholism. Today it is on the market in the 1-




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glutamine form. In experiments with drinkers, it appears to mitigate the effects of alcohol and to prevent hangovers when taken before drinking and relieve them when taken afterward in doses of two to four grams. Glutamine has the capacity to directly nourish the brain. It cannot be obtained from dietary protein. Tryptophan, sleep aid and antidepressant. This is an essential amino acid, supplied in the diet by such foods as milk, chicken, turkey, beef, peanuts, yoghurt, and cheese. Because of either a low-protein diet or an amino-acid imbalance, some people do not obtain enough of the substance. Tryptophan is needed by the brain to produce serotonin, a vital neurotransmitter that exerts a calming effect on the nervous system. When serotonin is undersupplied, anxiety, depression, and insomnia may result. In many cases the administration of tryptophan will relieve these symptoms. (Usual daily dosage is one or two grams on an empty stomach.) Phenylalanine for weight loss, Phenylalanine is an amino acid abundant in cheddar cheese, beef, lamb, nuts, brewer's yeast, and wheat germ. Some people may be deficient in phenylalanine, which is essential in creating epinephrine, a hormone that mobilizes the body's energies and is important in the burning up of fat reserves. According to Dr. Berger, phenylalanine is also an appetite suppressant. Here is his recipe for a "diet cocktail": one thousand milligrams vitamin C, five hundred milligrams phenylalanine, and one hundred milligrams vitamin B6. Take before bed, on an empty stomach, and it will lower your appetite the next day.




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WHAT VITAMINS CANNOT DO FOR YOU

Vitamins are not a cure-all. They cannot for instance: 1.Compensate for a mediocre diet. If you live on coffee, doughnuts, and fast-food dinners, no amount of vitamin-mineral supplementation is going to make you healthy, though it may prevent extreme malnutrition. Trying to improve a bad diet with vitamins is like trying to turn kerosene into high-octane fuel by pouring in an additive - it won't work. To get the maximum benefit from vitamins, you need to consume adequate amounts of meat, fowl, fish, nuts, whole grains, dairy products, and vegetables. 2. Make up for lack of exercise. Nature and evolution have designed the human body for exertion, not rest. If you lead a sedentary life, never standing when you can sit, never walking when you can ride, and never lifting anything heavier than a box of Kleenex, you can expect to suffer physically, no matter how good your diet and nutritional supplements are. Women are luckier than men in this respect - female hormones tend to prevent cardiovascular deterioration in sedentary women until middle age or, in some cases, the onset of the menopause. This merely postpones the inevitable, however. Look around you and you will see hundreds of inactive women in their fifties and sixties who suffer from high blood pressure diabetes, and other ailments or are so weak they barely have the strength to open a door, get up from a chair, or climb a flight of stairs. You don't have to be a super jock to maintain physical fitness - just exert yourself regularly. Spend fifteen to thirty minutes a day jogging, walking briskly, dancing, playing Ping-Pong or racketball, skipping rope - anything that will elevate your pulse, get you slightly out of breath, and cause you to break out in a mild sweat. Carefully lift a heavy object - forty to seventy pounds - for thirty seconds. Do a few minutes of callisthenics, stretching exercises, or yoga in which you move all the joints of your body as far as they will go in every direction. This simple daily regimen should be enough to keep you in reasonably good shape. 3. Redeem you from an unhappy, frustrated, stressful life. Some of the most unhealthy-looking people of your age who look skinny, sallow, tense, may be nutrition fanatics. They haunt health-stores, take double doses of every known nutritional supplement, eat only "approved" foods such as granola, wheat germ, yoghurt, beef liver, tofu, and organically grown vegetables. Nevertheless, they may suffer from depression, anxiety, insomnia, skin problems, and indigestion, to name only a few of their problems. They may have problems at home or at work. Despite all this unpleasantness they blame only poor nutrition, not their life-style, for whatever problems they encounter. Are they despondent? Is it because there is too much copper or not enough selenium in their diet. Angry and discontent? Maybe their body has become unable to absorb calcium, etc. These people believe in magic rather than the actuality of nutrition. What they really need is counselling, the gumption to turn their lives around, or both.




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4. Substitute the traditional therapy in cases of serious or life-threatening disease. Though vitamin therapy may help or relieve many serious complaints, not one of the provitamin experts believes that a patient should self-medicate with nutrients instead of seeking medical advice. Vitamin therapy is something you should try in addition to medical treatment.




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CAN VITAMINS BE BAD FOR YOU? In general, vitamins are harmless to adult users except when administered in absurdly high doses. Even then, the bad effects are temporary and will be reversed when dosages are lowered. This is not the case with infants and small children, who are much more susceptible to nutrient overdose. Do not give vitamins to an infant without the consent of a doctor. For a grown-up, the fat-soluble vitamins A and D are potentially the most troublesome. Since these vitamins are stored in the body, they can reach toxic levels when oversupplied. You should not take more than twenty-five thousand international units (I.U.) of A or one thousand I.U. of D daily except on the advice of your physician. The B vitamins are water-soluble and do not build up in the body. Any excess of a B vitamin is usually excreted harmlessly. Nevertheless, there are precautions you should take. B is a group of vitamins that work together as a complex. Do not use large doses of one B vitamin without supplying moderate doses of all the others, because this will aggravate any existing deficiencies. Be careful of vitamin B6: Recent reports show that B6 in megadoses above five hundred milligrams can produce temporary nerve damage. Do not take more than two hundred milligrams of B6 per day except under the careful supervision of a doctor. Vitamin C is safe in doses up to five grams (five thousand milligrams) or more. Some people, however, suffer indigestion or diarrhea when taking ascorbic acid in gram quantities. If this should happen, switch to sodium ascorbate ( a non-acid form of C). Vitamin E can be dangerous in high dosages (more than four hundred I.U. per day), especially to patients with arterial disease, who may react badly because E causes the heart to beat more vigorously. If you suffer from hardening of the arteries, do not take E without consulting your physician. Minerals are potentially much more dangerous than vitamins. Of the minerals recommended in this article, iron, magnesium, and selenium can be extremely toxic in large amounts. Do not take them in dosages larger than advised.

WHICH VITAMINS DO YOU NEED - AND IN WHAT AMOUNTS?

The following chart is based on the recommendations of provitamin physicians who believe in supernutrition - taking nutrients in a quantity sufficient to ensure full nutrition of all the cells. The basic dosages given are for the average, more-or-less healthy individual. If you are free of major diseases and do not suffer much from colds, headaches, allergies, and other minor complaints, this is the dosage you should start with.




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Someone moderately unhealthy - subject to insomnia, nervousness, respiratory infections, weakness, fatigue, skin trouble, and frequent minor infections - may require a higher dosage. If you are seriously ill with a debilitating or life-threatening disease or a mental/emotional complaint, such as acute depression, the topmost dosages are probably indicated. (In addition, you should put yourself in the care of a nutritionally trained physician.) Other factors are also important in deciding your dosage. You will need extra-generous amounts of vitamins if you: smoke drink alcohol exercise strenuously take the Pill get inadequate sleep drink a lot of coffee or tea take antibiotics or strong medication take illicit drugs like marijuana or cocaine are on a reducing diet are under physical or emotional stress VITAMINS BASIC DOSAGE HIGHER DOSAGE Vitamin A (retinol) 10,000 I.U. 25,000 I.U. Helps resist infection, builds healthy skin and organ tissue, promotes healthy eyes and vision. VITAMINS BASIC DOSAGE HIGHER DOSAGE Vitamin B1 (thiamine) Essential for normal functi- 10 to 25 mgs. 50 to 200 mgs. oning if nervous system, muscles, and heart. Vitamin B2 (riboflavin) 10 to 15 mgs. 50 to 200 mgs. Essential for healthy eyes, skin, nails, and hair. Pro- motes growth and general health. Helps prevent cata- racts.




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Niacin 50 mgs. 100 to 200 mgs. Essential for nervous and circulatory systems. Maintains proper protein and carbohydrate metabolism. May prevent headaches and insomnia. Pantothenic acid 200 mgs. 400 to 500 mgs. Important for the release of energy from carbohydrates, fats, and protein. Vital to the proper functioning of the adrenal glands. Protects against physical and mental stress. VITAMINS BASIC DOSAGE HIGHER DOSAGE Vitamin B6 (pyridoxine) 10 mgs. 50 to 200 mgs. Essential for protein and fat metabolism and in formation of antibodies. Aids nervous system and brain functioning. Can relieve symptoms of epi- lepsy, cerebral palsy, and certain types of anaemia. Choline 100 to 200 mgs. 400 to 500 mgs. Important for the metabolism of fats. Helps regulate liver and gall bladder functioning. Useful in treating high blood pressure and kidney disease. Inositol 100 to 200 mgs. 400 to 500 mgs. Vital for hair growth and formation of lecithin. Useful against high blood cholesterol and hair loss.




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Folic acid 400 mcgs. 600 to 800 mcgs. Necessary (with vitamin B12) for production of red blood cells. Aids cellular growth and production of RNA and DNA. Helps prevent anaemia and gastrointestinal disorders. PABA (para-aminobenzoic 100 mgs. 500 to 1,000 mgs. acid) Prevents premature aging of hair. Useful against sun- burn and in treating certain skin disorders. VITAMINS BASIC DOSAGE HIGHER DOSAGE Biotin 150 t0 300 mcgs 200 t0 500 mcgs. Needed for protein, carbohydrate, and fat metabolism. Helps prevent skin disorders, muscle pains, and depression. Vitamin B12 (cobalamin) 100 mcgs. 300 to 500 mcgs. Necessary (with folic acid) for producing red blood cells. Protects against anaemia and nervousness. Vitamin C 1,000 to 2,000 mgs. 3,000 to 5,000 mgs. (ascorbic acid) Essential for wound healing, production of red blood cells, and the formation of con- nective tissue. Protects against infection. Vitamin D 400 I.U. 600 t0 1,000 I.U. Aids the absorption of




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calcium and other minerals. Helps maintain healthy bones and teeth. Guards against muscular weakness. Necessary for a stable nervous system and normal heart action. Vitamin E (tocopherol) 200 t0 400 I.U. 600 to 1,200 I.U. Protects red blood cells and prevents blood clots. Vital in cellular respiration. May be essential for health of reproductive organs. MINERALS Calcium 400 to 600 mgs. 800 to 1,200 mgs. Builds bones and teeth. Normalizes metabolism. Aids in muscle action and in maintaining normal heart function. Acts as a natural tranquilliser and sleep- inducer. Magnesium 200 to 300 mgs. 400 to 600 mgs. Aids in the utilization of fats, carbohydrates, calcium, and other minerals. Essential for healthy muscles, heart, and bones, and for the synthesis of proteins. Iron 10 to 18 mgs. 20 to 25 mgs. Needed to make hemoglobin, which carries oxygen throughout the body. Helps in protein metabolism. Prevents anaemia. Zinc 30 to 50 mgs. 75 to 100 mgs. Promotes healing of wounds.




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Helps synthesize body protein. Necessary for production of male hormones. Selenium 75 to 100 mcgs. 150 to 300 mcgs. Antioxidant. Acts to make vitamin E more efficient in the body. EXERCISES A. After you have carefully read the text consulting your dictionaries make a list of the most important words in the text. (key words) giving the Croatian equivalent as well. B. 1. Composition of the text. Number the paragraphs in the passage. Give a key sentence for each paragraph. 2. Which are the two opposite opinions considering vitamin and mineral supplementation to our diet mentioned in the passage. Give your opinion on the subject. 3. Make a list of food supplements discussed in the passage. 4. Name food supplements (if any) in the passage you have not heard of before. 5. Write a list of cases where vitamins or minerals cannot help:




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6. Write a short list of cases when vitamins and minerals can be dangerous to our health. 7. What are the absolute musts or must nots in case of vitamin and mineral use we must keep in mind all the time?




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NEW DISCOVERIES IN MINERAL NUTRITION

MAGNESIUM Much of the Western world does not get enough magnesium, and the result could be a higher incidence of heart disease and hypertension. That is because many areas are served by a soft-water drinking supply, which lacks the magnesium content of hard water. Magnesium plays a part in keeping your heart muscle beating rhythmically. People living in hard-water areas may complain that their soap will not lather as readily. On the other hand, the incidence of heart disease related deaths is 10.1 percent lower than in soft-water regions, according to the journal Magnesium. Additionally, studies show a relationship between low magnesium levels and high blood pressure and stroke. Your muscles, bones, nerves and teeth also need this multipurpose mineral. At the University of California at Davis, rats fed a magnesium-deficient diet ran out of gas faster than their brother rats, who consumed a normal diet. This research suggests that the rats' exercise capacity declined along with the magnesium in their diet. People who attempt suicide may have low levels of magnesium in cerebrospinal fluid, according to a research in Hungary. Magnesium is thought to be necessary for the release of serotonin, a neurotransmitter that strikes a balance between manic depressed behaviour. The Recommended Daily Allowance for magnesium is from 300 milligrams for women to 350 milligrams for men. Nuts and whole-grain cereals are good food sources of magnesium.

CALCIUM Calcium helps build up your bones and helps prevent osteoporosis. Exercise helps speed the calcium along on its way to your skeleton. When you are inactive, your body decides you do not need as much calcium, and the mineral is flushed out of your bones, a little at a time. Of all the minerals in your body, calcium is the king. There is more of it than of any other mineral. Without it, your blood could not clot, your teeth would turn to mush and your heart would not beat properly. We also know that men consume more calcium-bearing foods than women do. It is thought to be one of the reason women are more at risk from osteoporosis.




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SELENIUM

Scientists first became interested in selenium because of its toxic effects. Livestock grazing on selenium-laden soil developed corroded hooves. In the course of subsequent research, scientists came across evidence that selenium might reduce the incidence or tumours. That marked the beginning of cancer research with selenium. To track the relationship of selenium to cancer in humans, researchers have collected blood samples and followed up to see who developed cancer. So far, a majority of studies have linked higher selenium levels with a lower risk of cancer. Because the line between "safe" and "dangerous" levels of selenium is small, other researchers are working to develop man-made selenium-containing compounds, that have fewer toxic effects, but can still suppress tumours. The compounds they developed are promising. Even at a higher dose levels, these compounds are not toxic to lab animals. GLOSSARY - NEW DISCOVERIES IN MINERAL NUTRITION incidence, n. - pojavljivanje; rasprostranjenost hypertension, n. - povišen krvni pritisak, hipertenzija serve, v. - poslužiti; opskrbiti; supply, n. - opskrbljivanje; snabdijevanje; opskrba vodom; vodovod lack, v. - nedostajati; manjkati; oskudijevati; biti u pomanjkanju content, n. - sadržaj; hard water - tvrda voda soft water - meka voda heart muscle - srčani mišić rhythmically, adv. - ritmički lather, v. - sapunati (se), pjeniti (se) readily, adv. - spremno according to, adv. - prema high blood pressure- visoki krvni pritisak stroke, n. - moždani udar; kap feed, fed, fed, irr,v. - hraniti capacity, n. - sposobnost decline, v. - gubiti se; opadati; nestajati; nazadovati attempt, v. - pokušati suicide, n. - samoubojstvo cerebrospinal fluid - moždana tekućina to strike a balance - staviti u ravnotežu nuts, n. - orašasto voće whole-grain cereals- žitarice od cjelovitog zrnja build up, v. - izgraditi prevent, v. - spriječiti




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flush out, v. - isprati; otplaviti a little at a time - malo pomalo clot, v. - zgrušavati se mush, n. - kaša hoof, n. pl: hooves - kopito livestock, n. - stoka graze, v. - kretati se, dotaknuti u prolazu blood sample - uzorak krvi suppress, v. - spriječiti, obuzdati, zaustaviti beat, beat, beaten, irr. v. - lupati, kucati, udarati, magnesium-deficient diet - prehrana s nedostatkom magnezija run out of gas - ostati bez daha, snage, sape; iscrpiti se; istrošiti se manic and depressed behavior - manično-depresivno stanje calcium-bearing foods- hrana koja sadrži kalcij EXERCISES A. After you have read the text read it again and try to find the answers to the following questions: 1. What is the problem with magnesium in the Western world? 2. What can a lack of magnesium result in? 3. Which has a higher level of magnesium content, soft water or hard water? 4. What is the reason soap does not to lather readily? 5. Why is magnesium important for our health? 6. What happened to rats at the University of California at Davis? 7. What psychological effects can low levels of magnesium have on people and why? 8. What is the daily Recommended Dietary Allowance for magnesium? 9. Which are good food sources of magnesium? B. After answering the questions in exercise A. read carefully the texts on Calcium and Selenium and write as many questions you can think of. Then ask your colleagues to answer them. Work in pairs.




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THE STORY OF MERCURY AND MAN

The world-wide alarm at the threat to human health presented by undue concentrations of mercury in the environment is an example of the consequence of interfering with the balance of nature. Mercury, and some other rare metals, are present in all forms of life, in small but necessary amounts. They become dangerous only when concentrated by man's activities. While mercury has been present in the environment for as long as man has inhabited the earth, it has only recently caused concern. All forms of life carry traces of mercury derived from their ancestry in the sea - and man, at the top of the food chain, carries more than most. We may thus have developed not only the tolerance for, but a dependence upon, 30 to 50 parts per billion of mercury found in the body. The hazardous factor today is any variation in the amount or type of mercury that the body absorbs. Man's greatest exposure to mercury is in food; studies since the 1930s show small but definite traces in many staples. While world-wide levels have changed little in 30 years, dangerously high concentrations have developed in some areas. Mercury is used in making antiseptics, floor waxes, paint preservatives, paper, and fungicides - and some goes to waste. It was once thought that such waste mercury sank harmlessly into the soil - but it is now known that this is not the end of it. Although it is relatively harmless as a pure metal, it forms extremely poisonous organic compounds. When concentrated in a river bed, for example, it is attacked by bacteria and converted into deadly methyl mercury. This substance is taken up by algae and then by fish; in the Minimata Bay disaster in Japan, the victims were eating fish with 100 times the "safe" level of mercury. So far, no one has suggested how to prevent mercury wastes from being methylated by bacteria, and then entering the food chain. A particularly dangerous form of mercury is ethyl mercury, widely used in fungicides to prevent deterioration of seed grains and growing crops. If such grains are eaten, or get into the food chain through domestic birds, illness and death may occur. Studies in Sweden also show chromosome damage from high mercury levels suggesting long-term genetic effects. Many countries have consequently banned the use of methyl and ethyl mercury compounds from use on food crops. GLOSSARY THE STORY OF MERCURY AND MAN world - wide - širom svijeta alarm, n. - uzbuna threat, n. - prijetnja; strah, panika undue, adj. - prekomjeran; nerazmjeran mercury, n. - živa interfere, v. - kositi se, djelovati u obratnom smjeru uplitati se; (u)miješati se, štetno djelovati




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concern, n. - zabrinutost; nemir, briga trace, n. - trag ancestry, n. - porijeklo; preci tolerance, n. - snošljivost; podnošljivost; tolerancija; dopušteno odstupanje dependence, n. - ovisnost hazardous, adj. - opasan staple, n. - (glavni) proizvod, roba, sirovina, sastojina wax, n. - vosak paint, n. - boja, ličilo preservative, n. - konzervans fungicide, n. - fungicid waste, n. - otpaci; otpadne vode; kanalizacija sink, sank, sunk, irr. v.- potonuti; sleći se; taložiti se river bed - riječno korito seed, n. - sjeme; sjemenka grain, n. - zrno growing crops - usjev u rastu domestic birds - domaće ptice ban, v. - zabraniti; izbaciti EXERCISES A. Give Croatian equivalents for the following words: methyl mercury - methylated - ethyl mercury - B. Answer the following questions: 1. What are the consequences of interfering with the balance of nature? 2. To what extent is mercury necessary in our life? 3. Is mercury always dangerous? Give an example. 4. How long has mercury been present in the environment? 5. How is mercury distributed in all forms of life? 6. What amount of mercury is tolerable in our bodies?




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7. What is the greatest danger in man's exposure to mercury? 8. How do we use mercury? 9. Is mercury dangerous as a pure metal? 10. When is mercury poisonous? 11. What happens to mercury after it is concentrated in a river bed? 12. What happened in Minimata Bay? 13. How can seed grains and growing crops become polluted by mercury compounds? C. Paragraph 1. In the sentence: "The world-wide alarm at the threat to human health presented by undue concentrations of mercury in the environment is an example ... ." a) The word presented is a ________________________ (verbal form) b) It actually presents a short form of a ________________ clause. c) Rewrite the whole sentence in its longer form. d) Now you have got a true ___________________ sentence. e) Now try and write this sentence in active form. _____________________________________________________________ 2. Paragraph 2 Sentence 1: "While mercury has been present in the environment for as long as man "has inhabited the earth, ...... a) The underlined verbal forms are ________________________ b) Find more of these verbal forms in Paragraph 2 and copy them in the space below.




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c) What other verbal forms can you find in Paragraph 2? Make a list of these forms in the space below. d) Analyse and discuss in the same way the various verbal forms in Paragraph 4. First find out how many different verbal forms you can find in Paragraph 2. Then make your lists.




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BIBLIOGRAPHY 1. Raymond Chang: Chemistry, McGraw-Hill, Inc. 1991, New York 2. William L. Jolly: Modern Inorganic Chemistry, McGraw-Hill, Inc. 1991, New York 3. R. Parry, Ph. Dietz, R. Tellefsen, L. Steiner: Chemistry, Prentice Hall, 1985, New Jersey 4. Morrison and Boyd: Organic Chemistry, 1973, Allyn and Bacon, Inc., USA 5. Guy Waller. Teach Yourself Chemistry, 1987, Hodder and Stoughton, London 6. J. Carter, P. Bajema, R. Heck, P. Lucero: Physical Science, 1979, Ginn and Company, Lexington, Mass. 7. Ch. Bickel, N. Eigenfeld, J. Hogg: Physical Science Investigation, 1989, Houghton Miffin Company, USA 8. W. Keeton and J. Gould, Biological Science, 1986, W.W. Norton & Company, Inc., New York 9. J. Postlethwait and J. Hopson: The Nature of Life, 1989, McGraw-Hill, New YorkB.S. 10. Beckett: Biology, 1976, Oxford University Press, Oxford 11. J. Hassall: Biology, 1988, Charles Letts & Co Ltd, London 12. J. Mclaren, J. Stasik, D. Levering: Life Science, 1981, Houghton Miffin Company, USA 13. N. Rothwell: Understanding Genetics, 1983, Oxford University Press, Oxford 14. R. Tamarin: Principles of Genetics, 15. K. Talaro and A. Talaro: Foundations in Microbiology, 16. R. Scott Stricoff and D. Walters: Laboratory Health and Safety Book, 1990, John Wiley & Sons, Inc.,New York 17. D. Clarke and E. Herbert: Food Facts, The British Council, 1994 18.. K. Hartvig and N. Rowley: You Are What You Eat, 1996, Piatkus Publishers Limited, London 19. E. Coulson: Food Science, 1974, Longman Group Limited, London 20. B. Fox and A. Cameron: Food Science, 1978, Hodder and Stoughton, London 21. S. Prescott and B. Proctor: Food Technology, 1987, McGraw-Hill, Inc., New York 22. P. Bostick Reed: Nutrition. An Applied Science, 1980, West Publishing Company, St. Paul, Minnesota. 23. W. Root: Food, 1980, Simon and Schuster, New York 24. J. Mariani: American Food & Drink, 1983, Ticknor & Fields, New Haven and New York 25. J. Kirschmann and L. Dunne: Nutrition Almanac, 1984, McGraw-Hill, New York 26. D. Chiras: Environmental Science, 1991, The Benjamin/Cummings Publishing Comp. Calif. 27. Ch. Kupchella and M. Hyland: Environmental Science, 1989, Allyn and Bacon, Boston 29. B. Bucholz: Principles of Environmental Management, 1993, Prentice-Hall, Inc. New Jersey 30. I. Pearson: English in Biological Science, 1985, Oxford University Press, Oxford 31. Bill Mascull: Key Words in Science & Technology, Harper Collins Publishers, 1997 32. F. Zimmerman: English For Science, 1989, Prentice-Hall, Inc., New Jersey 33. A. Sonka: Skilfull Reading, 1981, Prentice-hall, Inc., New Yersey 34. D. Curry: Short Readings in Science, 1984, English Language Programs Division, Washington D.C. 35. L. Trimble: English for Science and Technology, 1985, Cambridge University Press, Cambridge 36. K. Croft and B. Brown: Science Reading, 1986, Educational Services, Washington, D.C. 37. V. Booth: Communicating in Science, 1993, Cambridge University Press 38. M. Baudoin, E. Bober, M. Clarke, B. Dobson, S.Silberstein: Reader's Choice, 1988, The University of Michigan Press, USA 39. The Cassel Dictionary of Science, Cassell 1997, London 40. Dictionary of Science and Technology, Larousse, 1995, New York 41. Some of the articles have been adapted from various newspapers, magazines and periodicals, such as: Scientific American, New Scientist, Prevention, Health, Time, Newsweek and National Geographic.

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