Question

Suppose there were plants that had a high concentration of chlorophyll b, but lacked chlorophyll a, would it carry out photosynthesis? Then why do plants have chlorophyll b and other accessory pigments?

Answer 1

Part 1: Photosynthetic pigments

Part 2: Photosystems
The photosynthetic pigments along with certain complex protein and organic molecules, embedded in the thylakoid membrane is called photosystem. They play a crucial role in the light reaction of photosynthesis.

Part 3: Accessory pigments
Chlorophyll b, xanthophyll and carotenoids together are called accessory pigments. Their major function is to harvest light energy from the sun and pass it on to chlorophyll a. These pigments protect and prevent chlorophyll a from being photo oxidised.

Part 4: Reaction center
Chlorophyll a forms the reaction center in the photosystem. On absorbing energy, the electron from chlorophyll a gets excited and the light reaction occurs. Thus in the absence of chlorophyll a there will be no light reaction. Eventually no photosynthesis can occur.