4. Give a brief description of the process of synthesis of food in green plants.
5. Show with the help of a sketch that plants are the ultimate source of
1. Why do organisms take food?
2. Distinguish between a parasite and a saprotroph.
3. How would you test the presence of starch in leaves?
food.
Answers
1. Organisms need to take food to get energy and perform life processes.
2. Organisms which derive nutrition from the body of other living organisms are called parasites. Organisms which derive nutrition from dead and decaying matter are called saprotrophs.
3.Presence of starch in leaves can be tested by iodine test. Iodine turns starch solution into blue-black colour. Pour few drops of dilute iodine solution on the boiled leaf. The leaf becomes blue-black which proves the presence of starch in it.
4.The process by which plants make food is photosynthesis. Photosynthesis is the process in which green plants use sunlight to make their own food. Photosynthesis requires sunlight, chlorophyll, water, and carbon dioxide gas. Chlorophyll is a substance in all green plants, especially in the leaves.