Question

10. A variegated leaf with green and yellow patches in used for an experiment to prove that chlorophyll is required for photosynthesis. Before the experiment the green portions (A), and the pale yellow portions (B), are observed. What will be the colour of ‘A’ just before and after the starch test? Also write the equation of photosynthesis and mark, as well as validate from which molecule the by-product is obtained.

Answer 1

The colour of A i.e. the green portion before the starch test is pale yellow because chlorophyll needs to be removed before the starch test, and and after the test it's colour is blue-black because of the reaction of iodine and starch present in A.

The Equation of photosynthesis is :

6CO2  + 6H2O + Light energy  = C6H12O6  + 6O2

Answer 2

We know the green portion is A, and the pale yellow of the leaf is B.

While doing the starch test the chlorophyll needs to be removed, and the leaf turns pale yellow (B).

Now iodine is added, and the pale yellow leaf turns to blue back.  

Again the photosynthesis equation is 6 CO2 + 6 H2O = C6H12O6 + 6O2, and all this happens in the presence of sunlight.