Question

Fig. shows an experiment conducted to study a factor necessary for photosynthesis. Observe the diagram and then answer the following questions.

1. What is the aim of the experiment?
2. Name the test performed on the leaf and the solution used for the test.
3. What type of leaf was used for the experiment? Give an example.
4. What is the expected result of the above test on the parts labelled A and B.

Answer 1

1. To show that chlorophyll is necessary for photosynthesis.
2. Starch test. Solution used in Iodine solution.
3. Variegated leaf/Coleus leaf (leaf having non-green and green regions).
4. After performing the starch test, Part A turns brown, whereas Part B turns blue-black. This is because only Part B, which was green, had starch produced by photosynthesis due to the presence of chlorophyll. The result proves that chlorophyll is necessary for photosynthesis.