What is the Difference Between Chlorophyll A and B?

Chlorophyll A and B are two major types of chlorophyll found in plants and green algae, playing crucial roles in the process of photosynthesis. The main differences between Chlorophyll A and B are:

1. Primary vs. Accessory Pigment: Chlorophyll A is the primary photosynthetic pigment, while Chlorophyll B is an accessory pigment. Chlorophyll A absorbs light energy, while Chlorophyll B collects the energy to pass it on to Chlorophyll A.
2. Absorption Spectrum: Chlorophyll A absorbs light in the range of 430 nm to 660 nm (violet-blue and orange-red light), with the most effective absorption at 430 nm and 662 nm. Chlorophyll B absorbs light in the range of 450 nm to 650 nm, with the most effective absorption at 470 nm.
3. Reflection: Chlorophyll A reflects blue-green light, while Chlorophyll B reflects yellow-green light.
4. Presence: Chlorophyll A is present in all photosynthetic organisms on Earth, including plants, algae, bacteria, cyanobacteria, and phototrophs. Chlorophyll B is present only in green algae and plants.
5. Structure: In the porphyrin ring of Chlorophyll A, side groups of CH3 are present, while in Chlorophyll B, a CHO group is present other than CH3.
6. Photosystem: Chlorophyll A is the reaction center of the antenna array of core proteins in Photosystems I and II, while Chlorophyll B regulates the size of the antenna.

In summary, Chlorophyll A is the primary pigment responsible for photosynthesis, while Chlorophyll B is an accessory pigment that helps collect energy and pass it on to Chlorophyll A. They have different absorption and reflection spectra, and Chlorophyll A plays a more central role in the photosystems involved in photosynthesis.

Comparative Table: Chlorophyll A vs B

Here is a table comparing the differences between chlorophyll A and B:

Both chlorophyll A and B play crucial roles in the process of photosynthesis. Chlorophyll A is the primary pigment responsible for photosynthesis, while chlorophyll B is an accessory pigment that absorbs sunlight and passes it on to chlorophyll A.