Question

Main difference between chlorophyll a and chlorophyll b is
A) $-C{{H}_{3}}$ of chlorophyll a is replaced by $-CHO$ in chlorophyll b.
B) Chlorophyll a is linear while chlorophyll b is branched.
C) Chlorophyll a has no Mg.
D) All the above.

Answer 1

Hint:Chlorophyll is the molecule that absorbs sunlight and uses its energy to synthesise carbohydrates from $CO_2$ and water.Every chemical compound has a specific wavelength at which the enzyme shows the maximum and efficient absorption power.

Complete answer:
Chlorophyll is a green color pigment that is found in the leaves of the plant and it is the pigment which gives leaves its green color. Two forms of chlorophyll a and b present themselves with various differences between them. The principal pigment that captures the sunlight during the process of photosynthesis is chlorophyll a while chlorophyll b captures and passes it to chlorophyll a. However this is not the major difference between them. Let us analyse the options to find the main difference between chlorophyll a and chlorophyll b.

>Option A: Chlorophyll a differs from chlorophyll b in that chlorophyll a has a methyl $(-C{{H}_{3}})$ group while chlorophyll b has a aldehyde group $(-CHO)$ in place of a methyl group. Therefore, this is the correct option.
>Option B: Both chlorophyll a and b have a cyclic structure. Therefore, this is the incorrect option.
>Option C: Magnesium (Mg) is a central compound in plants that is required by the plants to absorb sunlight during the process of photosynthesis. Both chlorophyll a and b have magnesium for absorption of sunlight.Therefore, this is the incorrect option.
>Option D: Since one of the above mentioned options is correct, this is the incorrect option.

Thus, the correct answer is option (A) $-C{{H}_{3}}$ of chlorophyll a is replaced by $-CHO$ in chlorophyll b.

Note:There are four different types of chlorophyll,
-Chlorophyll a: It is used in oxygenic photosynthesis and absorbs energy from violet - blue and orange-red wavelengths.
-Chlorophyll b: It helps in conversion of huge amounts of light energy to chemical energy and absorbs energy from blue light.
-Chlorophyll c: It is found in certain marine algae and it absorbs light in the wavelength of 447 -452 nm.
-Chlorophyll d: It is found in cyanobacteria and it absorbs far red light.