Question1. Why do organisms take food?
Solution1:
Living organisms eat food to get energy, which is essential for performing growth and for the maintenance of their body.
Question2. Distinguish between a parasite and a saprotroph.
Solution2:
| Saprotroph | Parasite |
| These are the organism that takes nutrients from dead or decaying organic matter. | These are the organism that grows and feeds on a living organism. |
| Example: Fungi | Example: Cuscuta |
Question3. How would you test the presence of starch in leaves?
Solution3:
Iodine solution is used to test leaves for the presence of starch.
In order to perform this test, one needs to heat the plant leaf in boiling water for 30 seconds to 1 minute and after that heat it in boiling ethanol for a few minutes. Wash with water and spread onto a white tile and add a few drops of iodine solution. The parts of the leaf that contains starch will change their colour to blue-black.
Question4. Give a brief description of the process of synthesis of food in green plants.
Solution4:
Photo means light and synthesis means to combine. Photosynthesis is the process by which plants prepare their food. In this process green pigment in plants (known as chlorophyll) helps leaves to capture the energy of the sunlight. This energy is used to synthesise (prepare) food from carbon dioxide and water.
Question5. Show with the help of a sketch that plants are the ultimate source of food.
Solution5: Photosynthesis is the process by which plants synthesise food with the help of chlorophyll and carbon dioxide in the presence of sunlight. All living beings depend on plants, whether directly or indirectly. For example, plant-eater animals depend directly on plants, but carnivores depend indirectly on plants. The following sketch shows some examples of plant dependency.
Question6. Fill in the blanks:
(a) Green plants are called _________________ since they synthesise their own food.
Answer (a): Autotrophs
(b) The food synthesised by plants is stored as _________________.
Answer (b): Starch
(c) In photosynthesis solar energy is absorbed by the pigment called ___________.
Answer (c): Chlorophyll
(d) During photosynthesis plants take in ______________________ and release __________________ gas.
Answer (d): Carbon dioxide, Oxygen
Question7. Name the following:
(i) A parasitic plant with a yellow, slender and branched stem.
Answer (i): Cuscuta
(ii) A plant that is partially autotrophic.
Answer (ii): Pitcher plant
(iii) The pores through which leaves exchange gases.
Answer (iii): Stomata
Question8. Tick the correct answer:
(a) Cuscuta is an example of:
(i) autotroph (ii) parasite (iii) saprotroph (iv) host
Answer (a): Parasite
(b) The plant which traps and feeds on insects is:
(i) Cuscuta (ii) china rose (iv) pitcher plant (iv) rose
Answer (b): Pitcher plant
Question9. Match the items given in Column I with those in Column II:
Column I Column II
Chlorophyll Rhizobium
Nitrogen Heterotrophs
Cuscuta Pitcher plant
Animals Leaf
Insects Parasite
Answer 9:
Chlorophyll Leaf
Nitrogen Bacteria
Amarbel Parasite
Animals Heterotrophs
Insects Pitcher Plant
Question10. Mark ‘T’ if the statement is true and ‘F’ if it is false:
(i) Carbon dioxide is released during photosynthesis. (T/F)
(ii) Plants which synthesise their food 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)
Answer10:
(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)
Question11. 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
Answer11: Stomata
Question12. 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
Answer12: Leaves
Question13. Why do farmers grow many fruits and vegetable crops inside large greenhouses? What are the advantages to the farmers?
Answer13:
Many farmers grow fruits and vegetables inside the large greenhouses because it protects plants from blowing wind, rodents, birds etc. Greenhouses have many advantages, it provides optimum sunlight, temperature and water to the crop. It also protects the plants from harsh climatic conditions. Because of greenhouse farmers get maximum output.