5. Suppose there were plants that had a high concentration of Chlorophyll , but lacked chlorophyll , would it carry out photosynthesis? Then why do plants have chlorophyll b and other accessory pigments?
Chlorophyll-a molecules are essential for the process of photosynthesis as they act as antenna molecules. These molecules get excited by absorbing photons and emit electrons during cyclic and non-cyclic photophosphorylation. Chlorophyll a molecules form the reaction centres for both photosystems I and II. Due to these reasons, photosynthesis is absent in plants lacking chlorophyll a. Chlorophyll b, carotenoids and xanthophylls are accessory pigments. The major functions of these pigments are as follows
1. Absorption of light rays of different wavelengths and transfer of this energy to reaction centres.
2. Carotenoids and xanthophylls also protect the chlorophyll molecule from photo-oxidation.
Thus, it can be concluded that if any plant were to lack chlorophyll-a and contain a high concentration of chlorophyll-b, then this plant would not undergo photosynthesis.