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?
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
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Answers
Answer:
Living organism eat food to get energy, which is essential for performing growth and maintenance of their body.
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.
Iodine solution is used to test leaves for the presence of starch. You need to: heat a plant leaf in boiling water for 30 seconds (this stops its chemical reactions) heat it in boiling ethanol for a few minutes (this removes most of its colour)
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.
Show with the help of a sketch that the plants are the ultimate source of food. The food chain shows that the plant is the ultimate producer. Only plant can produce food and rest of other organisms are directly or indirectly dependent on it.
