Question: what is the structural difference between chlorophyll a and b?
Answer: Structural Differences Between Chlorophyll A and B The porphyrin ring of chlorophyll is where light energy is absorbed. Chlorophyll A and B differ in only one atom in a side-chain on the third carbon. In A, the third carbon is attached to a methyl group whereas, in B, the third carbon is attached to an aldehyde group.