Question

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?​

Answer 1

AnswEr :-

1. Organisms take food to obtain energy and carry out life processes such as respiration, digestion, reproduction, nutrition etc.

2. Parasites depend upon another organism for food and cause harmful effects to the host. Examples of parasites are - Cuscuta, Mosquitoes

Whereas, Saprotrophs are obtain nutrition from dead and decaying organic matter. Examples of saprotrophs - Fungi, some bacteria.

3. Presence of starch in leaves can be tested using iodine. Iodine turns starch solution into blue-black colour. Thus, the leaf turns blue-black.

Reference :-

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Answer 2

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1. The organisms need to take food to build their bodies, to grow, to repair damaged part of their bodies and to obtain the energy to carry out life processes. Food provide resistance to fight against diseases and protection from different infections.

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 matter. Examples: Fungi and some bacteria.

3. Steps to test the presence of starch in leaves :

Step 1 :- A fresh leaf is taken.

Step 2 :- The leaf is boiled in water for few minutes to soften the cells in the leaf.

Step 3 :- Now, dip this leaf in iodine solution.

Step 4 :- The color of the leaf will changes into blue black color when iodine is added to it which shows the presence of starch in it.