Question

Which pigment of the planttakes partin light reaction of photosynthesis ?

• A. xanthophyll
• B. chl -a
• C. carotene
• D. phycoxanthin

Answer 1

Answer: (B)

Chlorophyll $a$ is found in all photosynthetic plants except bacteria. Hence, it is termed as universal photosynthetic pigment or primary photosynthetic pigment because it performs primary reaction of photosynthesis which involves conversion of light into chemical or electrical energy.
Other photosynthetic pigments are thence called accessory pigments.
They absorb light energy of different wavelengths, broaden the spectrum of light absorption and hand over the energy to chlorophyll a through electron spin resonance.
Some of the chlorophyll a molecules function as reaction centres $(P_{700},P_{680})$. They bring about electrical charge separation and hence convert light energy into electrical energy.