1

Solutions to

Natural Sciences Grade 9

Textbook and Workbook

(A. Olivier) Version 1 - 2017

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2 Cells as the Basic Units of Life Practical Examination 1 – page 7

Exercise : Cells as basic units of life – page 9

1.1 A cell is the basic structural and functional unit of a living organism.

1.2 Microscopic. We cannot see them with the naked eye – we need a microscope to see a cell.

1.3 Plant and animal cells. 2.1 Structures in the cytoplasm of the cell. 2.2 Figure 1: Diagram of an animal cell

Figure 2: Diagram of a plant cell 2.3 1. cell membrane

2. mitochondria 3. nucleus 4. vacuole 5. cytoplasm

2.4 Function Part of cell Jelly –like medium

Cytoplasm

Contains DNA Nucleus Responsible for energy

Mitochondria

Surrounds contents of cell

Cell membrane

Space filled with cell sap

Vacuole

3 Structure Plants only

Animals only

Both

Nucleus

Cytoplasm

Cell membrane

Mitochon-dria

Large vacuole

Chloro-plasts

Cell wall

Flexible shape

Error in questions: question 4 should refer to a plant cell, while Question 5 should refer to an animal cell

4.1

4.2.1 Gives the cell a specific shape and sturdiness. Protects the inside of the cell.

4.2.2 Contains chlorophyll so that photosynthesis can take place

5.1

5.2 Nucleus. It controls all the functions of the cell.

3 5.3.1 Encloses the contents of the cell and

allows certain substances to move into and out of the cell

5.3.2 Contains organelles, chemical reactions take place in the cytoplasm and it maintains the shape of the cell

5.3.3 Cellular respiration takes place in mitochondria – energy is released during this process.

5.4 Vacuoles in plant cells are large and permanent, while those in animal cells are small and temporary.

6 Microscopic: organisms that can only be seen with a microscope, e.g. bacteria, viruses and some fungi Macroscopic: organisms that can be seen with the naked eye, e.g. humans, dogs, ants, etc.

7.1 Basic structural and functional unit 7.2 Group of cells with the same structure

and function 7.3 More than one type of tissue that form

a specific structure (e.g. a heart) 7.4 Group of different organs that work

together to carry out a common function

7.5 Consists of different organ systems that form one body

8 Electron microscope. A beam of electrons is shot at a small object that is covered with a thin layer of gold. Electrons bounce back from the surface to form an image that can be seen on the computer screen.

9.1 A. Eye piece B. Tube C. Course adjustment knob D. Fine adjustment knob E. Arm F. Revolving nosepiece G. Objectives H. Stage I. Stage clips J. Diaphragm K. Mirror or electrical light source L. Base

9.2 A. Lens you place your eye against. Can magnify object 10x

C. Moves tube up and down to focus on the object.

D. Used for final focus G. Lenses that ensure different

magnifications. J. Controls the amount of light that

moves to and through the object K. Reflects/shines light upwards

through the condenser to the opening in the stage.

10.1 Diagram of plant cells, e.g. onion cells 1. cell wall 2. vacuole 3. cytoplasm 4. nucleus

10.2 Diagram of plant cell 1. cell wall 2. chloroplasts

10.3 Diagram of animal cells, e.g. cheek cells 5. Nucleus 6. Cytoplasm 7. Cell membrane

10.4 Diagram of plant cell 1. Nucleus 2. Cytoplasm 3. chloroplasts

11.1 Figure 1: Animal tissue Figure 2: Plant tissue

11.2 Cells all have a similar shape. Lots of chloroplasts visible.

11.3

12.1 It is an unspecialised cell that can divide into different specialised cells

Diagram of a plant cell

Cell wall Nucleus

Cytoplasm Chloroplast

Diagram of an animal cell

Cell membraneNucleus Cytoplasm

4 12.2 Adult stem cells have been used for

many years in the treatment of diseases, e.g. certain blood cancers and immunological disorders (bone marrow transplants), replacing skin after major burns. New research show that stem cells could be used to treat heart disease, cerebral palsy, Alzheimer’s and Parkinson’s diseases, diabetes and spinal cord injury. Most of these disease currently have no cure.

Systems in the human body – page 15 Exercise 1: The digestive system – page 18 1.1 To break down food into nutrients that

can be transported to cells via the bloodstream.

1.2 Ingestion, digestion, absorption, excretion.

1.3 Digestive tract (mouth, oesophagus, stomach, small intestine, large intestine) and supporting organs (tongue, salivary glands, liver, pancreas). Teeth also play a role.

1.4 Peptic ulcers, diarrhoea, cirrhosis of the liver, etc.

2 Process Description Digestion Large molecules broken

down… Excretion Indigested food is excretedAbsorption Movement of molecules.. Ingestion Taking food through …

3 Mechanical digestion occurs when food is broken down physically by teeth (chewing, grinding). Chemical digestion occurs through the action of enzymes that break down food into small molecules.

4 Nutrients can only be transported to the cells via the bloodstream. Only small, soluble molecules are therefore useful. Food has to be digested in order to form small, soluble molecules.

5. Peristalsis

6.1 1. Mouth 2. Salivary glands 3. Oesophagus 4. Liver 5. Gallbladder 6. Stomach 7. Pancreas 8. Small intestine 9. Large intestine 10. Rectum 11. Anus

6.2 The human digestive system 6.3 Salivary glands 6.4.1 Mouth 6.4.2 Anus 6.4.3 Small intestine 6.4.4 Small intestine 6.5.1 Stomach 6.5.2 Oesophagus 6.5.3 Large intestine 6.5.4 Rectum 6.5.5 Gall bladder 7

14 13.2 Ovum 14 Approximately every four weeks.

Menstruation takes place if no fertilisation occurred.

15.1 Menstrual cycle 15.2 Usually the 14th day of the cycle 15.3 The 1st to the 5th day of the cycle. In

this example from about 14 February 15.4 20 February 15.5 If the wall is thicker it can contain

more blood vessels in preparation of the implantation of a fertilised egg

16 A: menstruation. The wall of the uterus breaks down and is excreted. B: the wall of the uterus recovers and thickens C: an ovum is released by one of the ovaries D: the wall of the uterus is thickened in preparation of the implantation of a fertilised egg

17.1 Menses; period 17.2 5 days 17.3 28 days 17.4 14th day 17.5 19th to 28th day 17.6 Ovulation can occur from the 13th to

the 20th. Next period may start on the 30th

18.1 Fertilisation 18.2 A: ovum

B: sperm 18.3 A: ovary

B: testes 18.4 The zygote has to implanted in the

wall of the uterus 19.1 A: uterus

B: Fallopian tube 19.2.1 Y 19.2.2 X 19.3.1 B 19.3.2 A 20 The lining of the uterus will break

down and the unfertilised egg (ovum) will be excreted during a process called menstruation.

21.1 Testes 21.2 Ovary 21.3 Fallopian tube 21.4 Uterus 21.5 Uterus 22.1 Fertilised egg 22.2 Fertilised egg that has been

implanted

22.3 The embryo is called a foetus once it has developed to a certain level

22.4 Mature foetus that is born 22.5 Hollow organ where the foetus

develops 23.1 1. uterine wall

2. placenta 3. umbilical cord 4. amniotic fluid 5. cervix

23.2.1 Provides oxygen and nutrients to the foetus and removes waste products from the foetus

23.2.2 Connect the foetus to the placenta 23.3 Pregnancy 23.4 Baby 23.5 If the baby is not lying with its head

down, this can cause complications during birth. A large baby can also be more painful.

24.1 A: placenta B: vagina

24.2 Oxygen and nutrients 24.3 Carbon dioxide and urea 24.4 Through the vagina 25.1 400 million 25.2 Thousands 25.3 The vaginal fluid is acidic and kills a

lot of sperm. Only one egg cell is released every month which makes the change of the sperm cell reaching the egg small.

25.4 One 25.5 In the Fallopian tube 25.6 A membrane forms around the

fertilised egg to prevent other sperm cells from entering

26.1 Male condom 26.2 It prevents sperm cells from entering

the vagina 26.3 Female condom 26.4

26.5 Vagina 26.6 It prevents sperm from entering the

vagina and uterus

15 26.7 The hormones in the Pill prevent egg

cells from being released 27.1 Smoking causes harmful substances

from passing through the placenta to the foetus. The foetus can be deprived of oxygen and its heart can be under stress

27.2 Drinking alcohol can lead to a miscarriage, stillbirth, premature birth and small birth weight. The baby can also get foetal alcohol syndrome.

28 It is the arrangement where one woman agrees to carry the baby for another person(s), who will become the baby’s legal parent(s) after birth.

Practical activity 1 – page 83 Hypothesis: the heart rate of the

learners will be higher after doing exercise

Independent variable: exercise done or not Dependent variable: heart rate Fixed variable: age of learners. You could also include mass or height of learners

Results: please note that these values will differ from your own.

Learner nr (boys)

Pulse before exercise

Pulse after exercise

1 68 112 2 72 120 3 71 118 4 72 125 5 70 114 Total 353 589 Average

70,6 117,8

Learner

nr (girls) Pulse before exercise

Pulse after exercise

6 72 125 7 73 118 8 70 120 9 70 125 10 72 121 Total 357 609 Average 71,4 121,8

Interpretation of Results:

You could also plot the average values only and make deductions from that.

Conclusion 1. Learner 1 (the first boy) as his

resting heart rate is low and his heart rate did not increase too much after doing exercise

2. Learner 9 (the second last girl) 3. Learner 5 and 1, 7, 3, 2, 10, 8, 4

and 6, 9 4. The average heart rate of boys is

lower than that of girls. Exercise 9: Circulatory and respiratory systems – page 85 1. The movement of air in and out of the

lungs. 2. STATEMENTS Inhala-

tionExhala-

tionIntercostal muscles relax 1. 2.

The diaphragm contracts 3. 4. Air is pushed out of the lungs 5. 6. The diaphragm becomes flatter 7. 8. The volume of the chest cavity increases 9. 10. The ribs move down and inward 11. 12. The pressure in the chest cavity reduces 13. 14. The diaphragm moves upwards 15. 16. Intercostal muscles contract 17. 18. The pressure on the lungs increases 19. 20.

020406080

100120140

1 2 3 4 5 6 7 8 9 10

Hear

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Learner number

Bar chart to show the effect of excercise on the heart rate of boys and girls

Before excercise

After excercise

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Boys Pulse before exercise

Boys Pulse after exercise

girls Pulse before exercise

GirlsPulse after exercise

Hear

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Bar chart to show the influence of exvercies on the heart rate of boys and girls

16 3. The muscles between the ribs

(intercostals muscles) contract and lift the ribs upwards and outwards. At the same time the diaphragm contracts and moves downwards. This makes the chest cavity larger and cause the air pressure in the chest cavity to decrease. The pressure inside the lungs is also decreased and air will move into the lungs (from higher pressure outside to lower pressure in the lungs) until the air pressure in the chest cavity and lungs are equal.

4. Carbon dioxide and oxygen are exchanged (swopped).

5. Cell membranes 6.1 1. Trachea

2. Lung 3. Bronchial tubes 4. Bronchioles 5. Alveoli 6. Lung sac

6.2 Oxygen and carbon dioxide 6.3 5 7.1.1 Higher 7.1.2 Lower 7.2.1 Oxygen 7.2.2 Carbon dioxide 7.3 The membrane is thin and permeable7.4.1 Before exercise: 500 cm3

During exercise: 1500 cm3 7.5 She in haled 3 times more during

exercise than before exercise 8 Air that is inhaled is high in oxygen.

the concentration of oxygen in the blood vessels next to the alveoli has a lower concentration of oxygen. The oxygen will diffuse from a high concentration in the alveoli to a lower concentration in the blood of the capillaries. Carbon dioxide will diffuse from a high concentration in the blood to a low concentration in the alveoli. Gaseous exchange can occur as the membranes of the cells of the alveoli are very thin.

9 Oxygen will diffuse from a higher concentration in the blood to a lower concentration in the body cells. Carbon dioxide will diffuse from a high concentration in the cell to a lower concentration in the blood.

10 It is the movement of blood through the body. In the process nutrients and oxygen are transported to cells and carbon dioxide and waste products are removed.

11.1

11.2 The heart pumps blood via the blood

vessels 11.3 To transport oxygen and nutrients to

all cells as well as to remove carbon dioxide and waste products from the cells

12 Heart: Function – pump blood through body. If left out - blood will not flow upwards. Blood: Function – transports gases, nutrients and waste material If left out – oxygen and nutrients won’t reach cells. If waste materials build up in cells, the cells will die. Blood vessels: Function – act as ‘pathways’ through which blood moves If left out – blood will move directly around all tissues If any of the above parts are left out, the person will die. From the above we know that all three parts of the circulatory system are essential. The parts work together to ensure effective functioning of cells.

heart

blood vessels

blood

17 13 1. Artery. Carries blood from the

heart to the rest of the body. Have thick, strong muscle walls as blood is transported at high pressure

2. Vein. Transport blood to the heart. Walls are thinner than that of arteries as pressure is lower.

3. Capillaries. Connect arteries to veins. Form networks around cells to provide cells with nutrient. Have very thin walls.

14.1 Arteries: Transport blood from the heart. Have a thick muscular wall Blood flows at high pressure Veins: Transport blood to the heart. Have a thinner muscular wall Blood flows at low pressure Capillaries: Connect veins and arteries Walls are very thin Low blood pressure

14.2 P. Lowest level of oxygen. Veins transport oxygen-deficient blood to the heart

15.1 1. Lungs 2. Left atrium 3. Left ventricle 4. Right atrium 5. Right ventricle 6. Liver 7.Kidney

15.2 A system with two pumps. One part of the heart pump blood into the lungs while the other pumps blood to the rest of the body.

16.1, 16.2 and 16.3

16.4 Gaseous exchange 16.5 Capillaries 16.6 More oxygen and nutrients are

needed by muscles. More carbon dioxide and other waste products are produced and these need to be removed faster. Therefore heart rate must increase to circulate blood faster.

17 Error in question: option D should read ‘pump blood into arteries’ E → D → F → C → B → A → G

18 1. F 2. Q 3. C 4. A 5. D 6. M 7. G 8. B 9. H 10. I 11. N 12. K 13. J 14. P 15. O 16. L 17. E

18 19 1. Aorta

2. Pulmonary artery 3. Upper vena cava 4. Left pulmonary veins 5. Right pulmonary veins 6. Left atrium 7. Right atrium 8. Heart valve 9. Left ventricle 10. Right ventricle 11. Septum 12. Lower vena cava

20.1

20.2 P: transports blood from body to

heart Q: transports blood from heart to lungs R: transports blood from heart to body S: transports blood from lungs to heart

20.3 Left side (close to ventricle) as the blood is pumped from here over a great distance to the rest of the body. Pressure is high.

20.4 Blood on the left side has more oxygen than that of the right side.

20.5 To prevent reflux 20.6 We measure the pulse rate. When

the heart beats, the heart muscle contracts and relaxes. This makes the arteries expand and contract slightly. We can feel this contraction when we put our fingers over the arteries.

21.1 A From the body B From the lungs C To the lungs D To the body

21.2.1

System 1: gaseous exchange

21.2.2

System 2: cellular respiration

21.3 System 1: blood that is low in oxygen and high in carbon dioxide is transported to the lungs. In the lungs gaseous exchange takes place. The oxygen-rich blood is then transported to the rest of the body. System 2: oxygen is needed for cellular respiration . Blood transports oxygen to the cells. Carbon dioxide is a product of cellular respiration and is transported away from the cells by the blood.

22.1.1 The more strenuous the activity, the faster the heart rate of the person will be.

22.1.2 Duration of activity, mass of person, age of person, fitness of person, etc.

22.1.3 Type of activity 22.2.1

22.2.2 Person C 22.2.3 Jogging 22.2.4 If the person is fit, it will be back to

normal (resting heart rate). If a person is very unfit, the heart rate will be lower than immediately after exercise but might still be higher than resting rate.

23.1 Reaction between glucose and oxygen that takes place in a cell.

23.2 In every living cell 23.3 Oxygen, glucose and enzymes 23.4 Carbon dioxide and water 24.1 Exercise increases the pulse rate 24.2 Jo. Jo’s pulse rate increases from 78

to 122, i.e. by 44 24.3 More oxygen is needed by the cells

and more waste products are produces. An increase in blood flow is needed to achieve this.

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The effect of activity on the heart rate of athletes

Before excercise

After excercise

19 24.4 When duration of exercise increases,

recovery time also increases. Practical activity 2 – page 98 Aim: To test if fat/oil is present in food Hypothesis: fat/oil is present in food Materials and equipment:

Food Ethanol Filter paper Mortar and pestle

Method: 1. Put a small amount of food in the

mortar 2. Add sufficient ethanol to cover the

food 3. Grind the food in the ethanol with

the pestle 4. Let stand so that the bits of food

settle on the bottom of the mortar 5. Carefully pour out a bit of the

liquid onto the filter paper 6. Leave until the ethanol has

evaporated Results and observation:

This will vary based on the food you used. If the food contains fat/oil you will observe a oily mark on the paper.

Conclusion: some foods contain fats/oils

Discussion: The interpretation of results in this test can be subjective. If a small amount of fat/oil is present, it might be missed. This test also does not indicate the amount of fat/oil or the type of fat/oil that the food contains. In order to maintain a balanced diet, it is important that we know which foods are rich in oils/fats, carbohydrates, proteins. An accurate food test is therefore useful.

Exercise 10: Digestive system – page 101 1.1 A diet that provides the body with all

the necessary nutrients 1.2 Food is the source of energy an

nutrients 1.3 Proteins, carbohydrates, fats and

oils, vitamins, minerals, fibre, water

2 Food Main nutrient

Main function

Meat Protein Building blocks of body. Required for growth and cell repair

Sugar, bread

Carbo-hydrates

Source of energy

Butter Fats and oils

Insulation, protective cover over nerve cells, source of energy

Lemons Vitamins Ensure correct function of various processes, resistance against disease

Apple, cabbage

Fibre Prevents constipation, reduces risk of colon cancer

3.1 Carbohydrates 3.2 Vitamins 3.3 Fibre 4.1 Is the medium in which the metabolic

processes take place. Is the solvent for nutrients.

4.2 We get our amino acids from proteins. Amino acids are essential part of the cell structure.

5.1 Less in Japan. South Africans eat a lot more fats and oils and less leafy greens.

5.2 More in South Africa as South Africans eat more sugar.

5.3 More leafy greens 6.1 Meat and eggs 6.2 Bananas and oranges 6.3 Nuts and eggs 6.4 Eggs for proteins (rebuilding cells

after exercise) and bananas for carbohydrates (source of energy)

6.5 Eggs 7.1 It is the harmful effects on the body

from too much or too little of the different food groups

7.2 Too few nutrients are taken in 7.3 Too much energy giving food is eaten8.1 Proteins 8.2 Iron 8.3 Not enough carbohydrates and fats 8.4 Vitamins