1.Why do organisms take food?
Food is essential for all living organisms because:
i) Food contains nutrients necessary for our body like: Carbohydrates, Proteins, Fats, Vitamins and Minerals.
ii) For survival
iii)For Energy
2.Distinguish between a parasite and a saprotroph.
3. How would you test the presence of starch in leaves?
Iodine test is performed to test the presence of starch in leaves.
STARCH + IODINE Solution ====> Blue black color
Steps in Iodine Test:
Take green leaves from plant placed in sunlight.
Boil leaves for five minutes then place it in alcohol.
Take out the leaves and put drops of iodine solution by dropper.
Blue spot will be formed that confirm presence of Iodine.
4.Give a brief description of the process of synthesis of food in green plants.
The process of synthesis of food in green plants is called as Photosynthesis. This process can be represented as:
CARBON DIOXIDE + WATER ====> Carbohydrates + OXYGEN
This takes place in presence of sunlight and Chlorophyll.
Plants use simple chemical substances like carbon dioxide, water and minerals for the synthesis of food. Complex chemical substances such as carbohydrates are the products of photosynthesis.
Solar energy is absorbed by the chlorophylls present in leaves/plants.
Oxygen is produced during photosynthesis.
Oxygen released in photosynthesis is utilized by living organisms for their survival.
5.Show with the help of a sketch that plants are the ultimate source of food.
6. Fill in the blanks:
(a) Green plants are called AUTOTROPH since they synthesize their own food.
(b)The food synthesized by plants is stored as STARCH.
(c)In photosynthesis solar energy is absorbed by the pigment called CHLOROPHYLL.
(d) During photosynthesis plants take in CARBON DIOXIDE and release OXYGEN gas.
7.Name the following:
(i) A parasitic plant with yellow, slender and branched stem. Cuscuta
(ii)A plant that is partially autotrophic. Insectivorous Plants
(iii) The pores through which leaves exchange gases. Stomata
8. Tick the correct answer:
(a) Cuscuta is an example of: (i) autotroph (ii) parasite (iii) saprotroph (iv) host
(b) The plant which traps and feeds on insects is: (i) Cuscuta (ii) china rose (iv) pitcher plant (iv) rose
9.Mark ‘T’ if the statement is true and ‘F’ if it is false:
(i) Carbon dioxide is released during photosynthesis. (F)
(ii) Plants which synthesise their food are called saprotrophs. (F)
(iii)The product of photosynthesis is not a protein. (T)
(iv) Solar energy is converted into chemical energy during photosynthesis. (T)
10. 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) Petals
11. Choose the correct option from the following:
Plants take carbon dioxide from the atmosphere mainly through their:
(i) roots (ii) stem (iii) flowers (iv) leaves
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