Chapter 1                               Nutrition in Plants

Nutrition: Nutrition is the mode of taking food by an organisms and its utilization by the body.

Nutrients: The components of food like carbohydrates, proteins, fats, vitamins and minerals are necessary for our body is called nutrients.
These are necessary for nourishment of our body.

 

Autotrophic Nutrition: The mode of nutrition in which organisms make food themselves from simple substances is called autotrophic nutrition. Auto means self and trophos means nourishment.

Heterotrophic Nutrition: The mode of nutrition in which organisms take in food prepared by the plants are called heterotrophic nutrition. Hetero means other and trophos means nourishment.

Photosynthesis:  Photosynthesis is a process in which a plant in the presence of sunlight with the help of carbon dioxide from the atmosphere and water from the earth to make or synthesize food.

Chlorophyll, sunlight, carbon dioxide and water are necessary to carry out the process of photosynthesis.

During photosynthesis chlorophyll containing cells of leaves, in the presence of sunlight, use carbon dioxide and water to synthesize carbohydrates.

Carbon dioxide (Co₂) + water         carbohydrate + oxygen

Photo = Light

Synthesis = to combine

 

 

Exercises

1. Why do organisms need to take food?
   Ans: All the organisms need to take food to build their bodies, to grow, to repair damaged parts of their bodies and provide energy.
2. Distinguish between a parasite and saprotrophs.
   Ans: Difference between a parasite and saprotrophs are as follows:-

Parasite	Saprotrophs
A plant which is derived of valuable nutrients is called parasite.	Plants which use saprotrophic mode of nutrition are called saprotrophs.

3. How would you test the presence of starch in leaves?
   Ans: – To test the presence of starch in leaves, these are the following steps:-
   i)First take a small leaf containing chlorophyll.
   ii) Put 2 – 3 drops of dilute iodine solution on it.
   iii) Observe for some times.
   iv) If there is any changes in colour of leaf.
   v) If it contain starch, it will turn into blue or black in colour.
4. Give a brief description of the process of synthesis of food in green plants.
   Ans:- The process of synthesizing of food in green plant is called Photosynthesis. It is a process in which a plant prepares its food in the presence of sunlight with the help of carbon dioxide from the atmosphere and water from the earth. Chlorophyll, sunlight, carbon dioxide and water are necessary to complete the process of Photosynthesis.
5. Show with the help of sketch that the plants are the ultimate source of food.
   Ans:- Here is a sketch which shows that plants are the ultimate source of food :-

   From plants we get flower, bud, leaves, stem and roots that we eat, and very often we cook vegetables which we get from plants, without plants our food chain is incomplete.
   From plants we also get fruits like pineapple, apple, mangoes, banana etc.

6. Fill in the blanks:
   a) Green plants are called Autotrophs since they synthesis their own food.
   b) The food synthesized by the plants is stored as starch.
   c) In photosynthesis solar energy is captured by the pigment called chlorophyll.
   d) During photosynthesis plants take in carbon dioxide and release oxygen.
7. Name the following:-
   a) A parasitic plant with yellow, slender and branched stem. Cuscuta
   b) A plant that is partially autotrophic. Pitcher plant.
   c) The pores through which leaves exchange gases. Stomata
8. Tick the correct answer:-
   a) Cuscuta is an example of
   Ans: Parasite
   b) the plant which traps and feeds on insects is
   Ans: Pitcher plant.
9. Match the items given in column I with those in column II :
   chlorophyll leaf
   Nitrogen                                 Rhizobium
   Cuscuta                                   Parasite
   animals                                   Heterotrophs
   Insects                                    Pitcher Plant
10. Mark ‘T’ if the statement is true and ‘F’ if it is false:-
    i) Carbon dioxide is released during photosynthesis. ( False)
    ii) Plants which synthesize their food themselves are called saprotrophs. ( False)
    iii) the product of photosynthesis is not a protein. (True)
    iv) Solar energy is converted into chemical energy during photosynthesis. ( True)
11. Choose the correct option from the following:
    which part of the plant take in carbon dioxide from the air for photosynthesis.
    Ans: Stomata
12. Choose the correct option from the following :
    Plants take carbon dioxide from the atmosphere mainly through their:
    Ans: Leaves