Question

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

Answer 1

Chlorophyll is a pigment. It is a chemical compound that helps in the absorption and reflection of specific wavelengths of light. Chlorophyll is present in cells of the thylakoid membrane of an organelle which is called the chloroplast. These pigments such as chlorophyll are responsible for the green colour of leaves.

Complete answer:
Chlorophyll is a compound that is found in all photosynthetic plants. It is present in the chloroplast of the leaves. In bacteria, chlorophyll is absent. It is also known as the primary photosynthetic pigment.
The structure of chlorophyll is tadpole-like. The Head part of the structure is called porphyrin which is composed of pyrrole rings that are linked by methine bridges. End part of chlorophyll consisting of phytol which is a long-chain alcohol.
There are five main types of chlorophylls that can be noticed and they are chlorophylls a, b, c, and d. A related molecule is found in some prokaryotes which is called bacteriochlorophyll. In plants, chlorophyll a and chlorophyll b play the major role in photosynthesis as photosynthetic pigments.
The main differences between chlorophyll a and chlorophyll b are as follows:

Chlorophyll a	Chlorophyll b
It acts as a primary photosynthetic pigment.	It is not the primary photosynthetic pigment.
It is the main type of pigment.	Chlorophyll b act only as accessory pigment.
Chlorophyll a can be present in all plants, algae, and bacteria.	Chlorophyll b found only in green algae and in the green plants.
The reflecting colour of chlorophyll a is blue-green.	Chlorophyll b reflects only yellow-green colour.
Side groups present in chlorophyll a is of $C{H_3}$.	Chlorophyll b CHO group is present instead of $C{H_3}$.
The chemical formula of chlorophyll a is ${C_{55}}{H_{72}}Mg{N_4}{O_5}$.	Chlorophyll b is ${C_{55}}{H_{72}}Mg{N_4}{O_6}$
Chlorophyll a contains methyl group in the third position of its chlorine ring.	Chlorophyll b contains an aldehyde group in the third position of its chlorine ring.

Note: Chlorophyll is a type of pigment present in the chloroplast of the green plants and algae. It mainly absorbs the sunlight and helps in photosynthesis. There are various types of chlorophyll found in the plants. Among them, chlorophyll a and chlorophyll b have a major function. They are different in features as well as different in structure. Chlorophyll a contains a methyl group and is the main pigment associated with photosynthetic process while chlorophyll b contains an aldehyde group and is the accessory pigment.