* Why do organisms take food?
2. Distinguish between a parasite and a saprotroph
.
3. How would you test the presence of starch in leaves?
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
food.
Answers
Answer:
ans 1 Organisms need to take food to get energy and perform life processes. A living organism undergoes many life processes like nutrition, respiration, digestion, transportation, excretion, circulation of blood, and reproduction. To perform all these life processes the organism needs energy and nutrients.
ans 2 Parasites are organisms that depend upon another organism (host) for food and cause harmful effects or dieseases to the host. Examples: Cuscuta (Amarbel), mosquitoes and head lice. saprotrophs are orgnisms that obtain nutrition from dead and decaying organic matter. Examples: Fungi and some bacteria.
ans 3 The presence of starch in leaves can be tested by the Iodine test. When we remove chlorophyll from the leaf by boiling it in alcohol and then put two drops of iodine solution, it is colour change to blue indicates the presence of starch.
ans 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.