Nutrition in Plants POINTS TO REMEMBER

1. All living organisms require food as a source of energy. 2. Nutrients: carbohydrates, proteins, fats, vitamins and minerals are the

components of food. These components of food are necessary for our body and are called nutrients.

3. Nutrition: It is the mode of taking food by an organism and its utilization by the body. 4. Autotrophic: The mode of nutrition in which organism make food themselves

from simple substances is called autotrophic (auto = self, trophos = nourishment) nutrition Therefore, green plants are called autotrophs.

5. Heterotrophs: The category of organisms that take readymade food prepared by the plants are called heterotrophs (heteros = other, trophos = nourishment). For example: Human animals etc.

6. Parasitism plants: Some plants take readymade food from other organism and harms them. Such plants are called parasites and the organism, that suffers are called host. For example: Cuscuta is a parasite.

7. Saprotrophs: The category of organism that take nutrients from dead and decaying matter are called saprotrophs and the mode of nutrition is called saprotrophic nutrition.

8. Symbiotic relationship: Some organism live together for their mutual advantage. This is called symbiotic relationship. For example: Lichens. In lichens, a chlorophyll containing partner which is an alga, and a fungus live together.

9. Insectivorous plants: Some plants trap the insects and eat it that come in their contact. Such insect eating plants are called insectivorous plants. For example: pitcher plant.

10. Photosynthesis: i. It is food making process in plants.

ii. The synthesis of food in plants occurs in all the green parts of it, especially leaves. iii. During photosynthesis, chlorophyll containing cells of leaves in the presence

of sunlight, use carbon dioxide and water to synthesis carbohydrates.

Sunlight Carbon dioxide + water Carbohydrate + Oxygen

Chlorophyll

iv.Stomata: These are the tiny pores present on the surface of the leaves. These pores are surrounded by ‘guard cells’. Such pores are called stomata.

11. Sun is the ultimate source of energy for all living organisms. 12. We have to add ferilizers and manures to soil from time to time to enrich the

fertility of soil that increases the production of crops. 13. Cholorophyll: A green plant pigment which absorb energy from sunlight,

enabling the plant to build up food as carbohydrates from carbon dioxide and water by photosynthesis.

14. Host: A plant or an animal that supports a parasite is called host.

Q.1. Why do organisms need to take food? Ans. Food is needed by all living species for the following purposes:

a) It meant for the general growth and development of an organism. If it is not in sufficient amount, then it shows insufficient growth and development.

b) It is meant to provide energy. We need energy for movements such as running, walking or raising our arm.

c) It is also needed by living being for repairing of their damaged parts. d) It gives us resistance against diseases and protects us from infections.

Q.2. Distinguish between a parasite and a saprotroph. Ans.

Parasite Saprotroph

1. A parasite takes the food from the organism on which it lives.

2. They feed on a living organism.

3. The organism on which it feeds is called host.

4. It deprives the host of valuable nutrients

1. They secrete digestive juices on the matter they live and convert it into a solution and then absorb it.

2. They feed on dead and decaying organism.

3. They do not feed on a living organism. 4. There is no host at all.

Q.3. How would you test the presence of starch in leaves? Ans.Presence of starch in leaves can be tested by Iodine Test. Iodine turns starch

solution into blue black colour. Q.4. Give a brief description of the process of synthesis of food in green plants. Ans. Leave of a plant have a green pigment called chlorophyll. In the presence of

sunlight, they use carbon dioxide and water to synthesise carbohydrate. Sunlight

Carbon dioxide + water Carbohydrate + Oxygen Chlorophyll

During the process oxygen is released. The carbohydrates ultimately get converted into starch. Carbon dioxide from air is taken through stomata. Water and minerals are absorbed by the roots and transported to leaves.

Q.5. Show with the help of a sketch that the plants are the ultimate source of food. Ans.

Fig 1.1. Plants capture solar energy by unique process called Photosynthesis Q. 6 Fill in the blanks:

a) Green plants are called …………… since they synthesise their own food. b) The food synthesised by the plants is stored as …………. . c) In photosynthesis solar energy is captured by the pigment called…………. d) During photosynthesis plants take in ……………… and release …………

Ans. a) autotrophs b) starch c) chlorophyll d) carbon dioxide, oxygen.

Q.7. Name the following: i. A parasitic plant with yellow, slender and tabular stem.

ii. A plant that has both autotrophic and heterotrophic mode of nutrition. iii. The pores through which leaves exchange gases.

Ans. i) Cascuta ii) Insectivorous plants iii) Stomata.

Q. 8 . Thick the correct answer:

a) Amarbel is an example of ( i) autotroph (ii) parasite (iii) saprotroph (iv) host

b) The plant which traps and feeds on insects is

(i) Cascuta (ii) China rose (iii) Pitcher Plant (iv) Rose Ans.

(a) (ii) Parasite (b) (iii) Pitcher plant.

Q. 9. Match the items given in Column I with those in Column II: Column I Column II

(i) Chlorophyll Bacteria (ii) Nitrogen Heterotrophs (iii) Amarbel Pitcher plant (iv) Animals Leaf (v) Insects Paradise Ans. Column I Column II

(i) Chlorophyll Leaf (ii) Nitrogen Bacteria (iii) Amarbel Parasite (iv) Animals Heterotrophs (v) Insects Pitcher plant

Q. 10. Match ‘T’ if the statement is true and ‘F’ if it is false: (i) Carbon dioxide is released during photosynthesis. (T / F) (ii) Plants which synthesis their food themselves are called saprotrophs. (T / F) (iii) The product of photosynthesis is not a protein. (T / F) (iv) Solar energy is converted into chemical energy during photosynthesis. (T / F) Ans. (i) F (ii) F (iii) T (iv) T. Q. 11. Choose the correct option from the following: Which part of the plant takes in carbon dioxide from the air for photosynthesis? (i) Root hair (ii) Stomata (iii) Leaf veins (iv) Sepals Ans. (ii) Stomata. Q. 12. Choose the correct option from the following: Plants take carbon dioxide from the atmosphere mainly through their:

(i) roots (ii) stem (ii) flowers (iv) leaves

Ans. (iv) Leaves.

ADDITIONAL IMPORTANT QUESTIONS

Q. 1. Name the components of food which are necessary for our body? Ans. Carbohydrates, proteins, fats, vitamins and minerals. Q. 2. What is nutrition? Ans. Nutrition is the mode of taking food by an organism and its utilization by the body. Q. 3. Why the leaves are generally green? Ans. Leaves generally green because they contain a green pigment called chlorophyll. Q. 4. Food making process in plants is called photosynthesis. In which part of the

plant does photosynthesis occur? Ans. Photosynthesis occurs in leaves. Q. 5. What are stomata? Ans. These are the tiny pores present on the surface of leaves. Q. 6. Name various mode of nutrition. Ans. Various modes of nutrition are:

(i) Autotrophic nutrition. (ii) Heterotrophic nutrition. (iii) Saprotrophic nutrition.

Q. 7. Why the plants are called autotrophs? Ans. Plants can make their own food from simple substances. Therefore plants are

called autotrophs.

Q. 8. What is the ultimate source of energy for all living organisms? Ans. The sun is the ultimate source of energy for all living organisms.

Q. 9. Why insectivorous plants eat insects? Ans. To fulfill their needs of nitrogen.

Q. 10. Why the parasites are named so? Ans. They are called parasites because they deprive the host’s valuable nutrients and

harm the host by causing diseases. Q. 11. What are saprotrophs? Ans. Organisms which take the nutrients in the form of solution from dead and

decaying matter are called saprotrophs.

Q. 12. What is symbiotic relationship? Ans. Some organisms live together and share shelter and nutrients and mutually

benefited. This is called symbiotic relationship.

Q. 13. “All animals depend upon the plants for food.” Justify the statement. Ans. We know that the source of energy for living organisms is food. All green

plants form the major part of food by simple inorganic substances like carbon dioxide and water in the presence of sunlight and chlorophyll. This is known as autotrophic (holophytic) nutrition. But in case of animals they cannot synthesise their food themselves. So all animals depend on the green plants for food.

Q. 14. Distinguish between an autotroph and a heterotrophy. Ans.

Autotroph Heterotroph

1. They are capable of synthesizing their own food.

2. They form the first trophic level of any food chain.

3. They usually contain chlorophyll.

1. They cannot manufacture their

own food. 2. They form the higher levels in

any food chain. 3. Chlorophyll are absent in them.

Q. 15. What are cells? Describe their structure in brief.

Fig. 1.2 Cell Ans. Cell is defined as the structural and functional unit of life. Cells can be seen

only under the microscope. The cell is enclosed by a thin outer boundary called cell membrane. Most cells have a distinct centrally located spherical structure called the nucleus. The cell contains a jelly like substance, i.e., cytoplasm, that contains a number of cell-organelles including nucleus.

Q. 16. Why the food making process in plants is called photosynthesis? Ans. The chlorophyll present in the leaves of the green plants help them to capture the

solar energy. This energy is used to synthesise food from carbon dioxide and water. Since the synthesis of food occurs in sunlight, it is called photosynthesis (photo: light, synthesis: to combine).

Q. 17. “In the absence of photosynthesis, life is impossible on the earth.” Explain.

Ans. In the absence of green plants there would not be the process of photosynthesis. The survival of almost all living organisms directly or indirectly depends upon the food made by the plants. Besides oxygen it is an example of interspecific interaction in which both the partners are benefited which is essential for the survival of all living organisms is produced during photosynthesis. Thus we can say that life would be impossible on the earth in the absence of photosynthesis.

Q. 18. What are lichens? Ans. Lichens are organisms in which an alga and a fungus live together. The fungus

provides shelter, water and minerals to the alga and in return, alga provides food which is prepares by photosynthesis.

Q. 19. What is the mode of nutrition in fungi? Ans. Fungi secrete digestive juices on the dead and decaying matter and convert it

into a solution. Then they absorb nutrients from it. This mode of nutrition in which organisms take in nutrients in solution form from dead decaying matter is called saprotrophic nutrition.

Q. 20. Discuss in brief about the mechanism of eating insects by pitcher plant. Ans. Pitcher plant: In insectivorous plant leaves are modified into a pitcher like

structure. The apex of the leaf forms a lid which can open and close the mouth of the pitcher. Inside the pitcher there are hair which are downwardly directed. When an inside lands in the pitcher, it slips inside and the lid closes. The trapped insect is entangled into the hair. The insect is digested by the digestive juices secreted in the pitcher.

Q. 21. What are parasites? Explain by taking the example of Cuscuta (Amarbel).

Cuscuta is a plant which looks like yellow thread like structures twining around the stem and branches of some trees (Fig. 1.4). It lacks chlorophyll but takes readymade food from the host plant. The plant on which it climbs is called a host. Since it deprives the host’s valuable nutrients, it is called a parasite. Q. 22. Explain why fertilizers and manures are needed to the fields from time to time. Ans. We know that plants absorb minerals nutrients from the soil. So their amounts in

the soil keep on declining. Fertilizers and manures contain nutrients such as nitrogen, potassium, phosphorous etc. Therefore, to overcome the deficit of these nutrients in the soil we need to add these fertilizers and manures from time to time.

Q. 23. How symbiotic bacterium called Rhizobium is important for the farmers? Ans. Usually a crop requires a lot of nitrogen. But they can not utilize atmospheric

nitrogen. They need it in soluble form. The bacterium called Rhizobium can convert atmospheric nitrogen into a soluble form. But Rhizobium cannot make its own food. So it lives in the roots of gram, peas, moong, beans and other legumes and provides them nitrogen. In return, the plant provides food and shelter to the bacteria. They have symbiotic relationship. This association is of great importance for the farmers.

Q. 24. What is autotrophic mode of nutrition? How plants prepare their own food? Ans. Autotrophic mode of nutrition. The mode of nutrition in which organisms

make food themselves from simple substances is called autotrophic (auto = self, trophos = nourishment) nutrition. Therefore, plants are called autotrophs.

Photosynthesis-Food making process in plants. The synthesis of food in plants takes place in leaves. Therefore all the raw materials must reach there. Water and minerals present in the soil are absorbed by roots and transported to leaves through stems. Carbon dioxide from air is taken in through the tiny pores present on the surface of leaves called stomata. The leaves have a green pigment called chlorophyll. It helps leaves to capture the solar energy. This energy is used to synthesise food by the process called photosynthesis. During photosynthesis, chlorophyll containing cells of leaves (Fig. 1.5) in the presence of sunlight, using carbon dioxide and water to synthesise carbohydrates. The process can be represented as an equation: Sunlight Carbon dioxide + Water Carbohydrate + Oxygen Chlorophyll During this process is released. The carbohydrate ultimately gets converted into starch.

Fig. 1.5. Schematic diagram showing photosynthesis

OBJECTIVE TYPE QUESTIONS Q. 1. Match the items given in Column I with those given in Column II.

Column I

Column II (i) Autotrophs (ii) Heterotroph (iii) Parasite (iv) Saprophyte (v) Symbiont (vi) Insectivorous

(a) Fungi (b) Lichen (c) Pitcher plant (d) Algae (e) Man (f) Cuscuta

Q. 2. Fill in the blanks space in the following statements: (i) All organisms take …………. and utilize it to get energy for the growth and

the maintenance of their bodies. (ii) Green plants synthesis their food themselves by the process of …………… they are called …………..

(iii) …………… energy is stored by the leaves with the help of chlorophyll. (iv) …………… derive nutrition from dead, decaying matter. (v) Plants like cuscuta take food from ………….. plant. (iv) All animals are categorized as ………… .

(vii) …………… is produced and …………. is utilized during photosynthesis. (viii) …………… is the site of reception of light energy in leaves. Q. 3. Choose the true and false statements from the following: (i) Food is essential for all living organisms. (ii) Leaves are the food factories of plant. (iii) Water comes into leaves through stomata in the form of vapours. (iv) Plants utilize the carbon dioxide dissolved in the water absorbed by the root

for photosynthesis. (v) The sun is the ultimate source of energy for all living organisms. (vi) Algae are saprotrophs. (vii) Cuscuta is a parasite. (viii) Saprotrophs take their food in solution form from dead and decaying matter. (ix) Insectivorous plants are partial heterotrophs. (x) Plants take atmospheric nitrogen through stomata and utilize as a nutrient. Q. 4. Choose the correct option in the following. (i) Which of the following is a nutrient? (a) Protein (b) Fat (c) Vitamins (d) All of these. (ii) Human being can be categorised as (a) heterotrophs (b) autotrophs (c) parasites (d) saprotrophs.

(iii) The food making process in plants is called as (a) glycolysis (b) photosynthesis (c) photolysis (d) chemosynthesis (iv) Which part of the plant is called its food factory? (a) Fruits (b) Seeds (c) Leaves (d) Flowers (v) Tiny pores present on the surface of leaves through which gaseous exchange occurs are called (a) stomata (b) guard cells (c) food holes (d) gas holes (vi) What is the ultimate source of energy for all living organisms? (a) Water energy (b) Wind energy (c) Solar energy (d) Chemical energy (vii) Green pigment present in the leaves is called (a) hemoglobin (b) globulin (c) albumin (d) chlorophyll (viii) During photosynthesis plants (a) take oxygen and release carbon dioxide. (b) take carbon dioxide and release oxygen (c) take carbon dioxide but do not release oxygen (d) take oxygen but do not release carbon dioxide (ix) During photosynthesis (a) solar energy is converted into chemical energy (b) solar energy is converted into mechanical energy (c) chemical energy is converted into mechanical energy (d) bio energy is converted into chemical energy. (x) The raw materials for photosynthesis are (a) CO2, water (b) CO2, O2, H2 (c) N2, water (d) O2, water (xi) The end products of photosynthesis are (a) carbohydrates, oxygen (b) carbohydrates, hydrogen (c) carbohydrates, water vapours (d) carbohydrates, oxygen and water vapours (xii) Which one of the following is a parasite? (a) Lichen (b) Cuscuta (c) Pitcher plant (d) Rhizobium (xiii) Which of the following class of organisms belongs to saprotrophs? (a) Fungi (b) Algae (c) Lichens (d) Bryophytes

(xiv) Which one of the following is a pair of symbolic organisms? (a) Lichens (b) Rhizobium and a legume (c) Cuscuta (d) Both (a) and (b) (xv) Which of the following is an insectivorous plant? (a) Pitcher plant (b) Indian telegraph plant (c) 4 O’clock plant (d) Cuscuta (xvi) Insectivorous plants eat insects to fulfill their needs of (a) energy (b) nitrogen (c) phosphorous (d) potassium

ANSWERS TO OBJECTIVE TYPE QUESTIONS Q. 1. Match the items in Column I with Column II

Column I Column II

i) Autotrophs ii) Heterotroph iii) Parasite iv) Saprotroph v) Symbiont vi) Insectivorous

d) Algae e) Man f) Cuscuta a) Fungi b) Lichen c) Pitcher Plant

Q. 2. Fill in the blanks: i) Food ii) photosynthesis, autotrophs iii) Solar iv) Fungi/saprotrophs v) Host vi) heterotrophs vii) Oxygen, carbon dioxide viii) chlorophyll. Q. 3. True/False: i) True ii) True iii) False iv) False v) True vi) False vii) True viii) True ix) True x) False. Q. 4. Choose the correct option: (i) (d) (ii) (a) (iii) (b) (iv) (c) (v) (a) (vi) (c) (vii) (d) (viii) (b) (ix) (a) (x) (a) (xi) (a) (xii) (b) (xiii) (a) (xiv) (d) (xv) (a)

(xvi) (b).