Question

Mention one difference in the structure of chlorophyll a and chlorophyll b.

Answer 1

Chlorophyll a and b are the only chlorophylls that occur in chloroplasts of higher plants. Chlorophyll a is found in all photosynthetic plants except bacteria. It is also called primary photosynthetic pigment.

Chlorophyll has a tadpole-like configuration with a head called porphyrin and a tail made up of long chain alcohol called phytol. Porphyrin head is made up of four pyrrole rings which are linked by methine bridges. The skeleton of each pyrrole ring is made up of 5 atoms- 4 carbon and one nitrogen. The external carbon atoms of the pyrrole rings have been given specific numbers, 1-8.

Chlorophyll b differs from chlorophyll a in having formyl group ($-CHO$) instead of a methyl ($-C{H}_3$) group at carbon atom 3.