Question

Why we should not test for glucose instead of starch in the green leaves?

• A. The glucose formed during photosynthesis gets polymerised into starch. So stable product one can test is starch.
• B. The glucose formed during photosynthesis gets polymerised into fructose. So starch gives a positive test.
• C. Both A and B.
• D. None of the above.

Answer 1

The correct option is A The glucose formed during photosynthesis gets polymerised into starch. So stable product one can test is starch.

Photosynthesis is the process of formation of organic food from carbon dioxide and water in the presence of sunlight where chlorophyll traps the solar energy in cells. Oxygen is produced as byproduct. Simple carbohydrate or sugar (e.g.glucose) is the main product from which other organic substances are formed. Excess of glucose is stored as starch to function as internal energy reserve to be used as and when required. So, we test starch instead of glucose in leaves. Starch develops a blue-black colour with iodine solution.

Therefore, the correct answer is option A.