Question

Steps involved in the test to check the presence of starch in a leaf are shown in figure 1, 2, 3 and 4. They are not in the correct sequence. Arrange them in proper sequence?

• A. 4, 1, 3 and 2
• B. 1, 3, 4 and 2
• C. 2, 1, 4 and 3
• D. 2, 3, 1 and 4

Answer 1

The correct option is A

4, 1, 3 and 2

Part of a leaf is covered to prevent it from photosynthesis (step 4). Then the entire leaf is dipped in boiling water for a minute to kill the cells (step1). Boil the leaf in methylated spirit over a water bath till it becomes pale white due to the removal of chlorophyll (step 3). The leaf now becomes hard and brittle. Place it again in hot water to soften it. Spread the leaf in a dish and pour iodine solution on it. The presence of starch will be indicated by a blue-black colour (step2).