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Chlorophyll A and Chlorophyll B
Chlorophyll is of five types but is used in two forms mainly- Chlorophyll A and Chlorophyll B. Chlorophyll are required by the plant to absorb the wavelengths of the sunlight and use them for producing food. This phenomenon is commonly known as ‘photosynthesis.’ A plant organelle called ‘chloroplast’ has a thylakoid membrane in whose cells Chlorophyll is present in abundance. Chlorophyll is essential for plants as it helps them to make food. Plants being the producers, require sunlight, water, oxygen, and glucose to make food, and chlorophyll plays a vital role in the phenomenon of photosynthesis.
The name chlorophyll and the discovery of chlorophyll’s credit go to the work done by ‘Joseph Bienaime Caventou.’ Both these pigments help provide beautiful green colour to the plants though being different in composition and structure.
Chlorophyll A: Overview
Although chlorophyll is present in five forms, the two main forms of Chlorophyll are A and B. The name of both the chlorophyll pigments is given based on the type of wavelengths they can absorb.
Chlorophyll A is the most common and abundant chlorophyll found in plants, algae and cyanobacteria. Chlorophyll A is known to absorb two wavelengths of blue and red, respectively. The molecular formula given to the structure of Chlorophyll A is C55H72O5N4Mg. Chlorophyll A is found mainly in all types of plants.
Phytoplankton reports a large quantity of chlorophyll in them. In an aquatic ecosystem, the quality of the water is determined by the number of phytoplankton present in them. As phytoplankton has an amount of chlorophyll A present in them, the quality of the water is determined by the number of phytoplankton present in them. Therefore, it can be deduced that chlorophyll A is also a biological indicator. Furthermore, Chlorophyll A is also known to be highly susceptible to oxidative stress.
Chlorophyll B: Overview
The colour of chlorophyll B is yellow. The molecular formula of Chlorophyll B is C55H70MgN4O6. The colour of the wavelength absorbed by Chlorophyll B is violet-blue. Algae, Prochlorophytes mainly have Chlorophyll B present in them. Single chlorine is present in them. A formyl group is present in it. Most plants have Chlorophyll B present in them.
Due to the difference in the structure of both the Chlorophylls, it is to be mentioned that Chlorophyll B is more polar than chlorophyll A. This is because their polarity differs due to the difference in their structure.
Chlorophyll A and Chlorophyll B: Difference
As the plants require both types of chlorophyll to carry out the process of photosynthesis, there are significant differences observed in their structures, functions and composition.
Chlorophyll A is highly important for plants to carry photosynthesis, but Chlorophyll B is not an essential substance. It is rather seen as an accessory colour pigment. 430-660 nm is the range of wavelength absorbed by Chlorophyll A. The range of absorption for Chlorophyll B is 450-650 nm approximately. Therefore, 831.5g/mol is the molecular weight of chlorophyll A. The calculated molecular weight of Chlorophyll B is 907.49g/mol.
As Chlorophyll A is found mainly in plants, algae and even in cyanobacteria, it can be deduced that they make up for the most amount of chlorophyll found in plants. On the other hand, chlorophyll B is not the major type of chlorophyll found in plants, so they make up almost 1/4 percent of the chlorophyll found in plants.
As their structure is different, their polarity varies. Chlorophyll B is more polar than Chlorophyll A due to the difference in their structure. The solubility also differs for both the pigments. Chlorophyll A is less soluble in polar solvents, and Chlorophyll B is more soluble in polar solvents. Green Algae has more chlorophyll B present in them.
Chlorophyll A and Chlorophyll B: Differences
| Chlorophyll A | Chlorophyll B |
| Commonly found in all the plants, algae and cyanobacteria | Commonly found in plants especially Green Algae |
| They are the main pigments | It is used as an accessory pigment by the plant |
| It has a methyl group present in its structure | It has a formyl group present in its structure |
| 831.5g/mol is their molecular weight. | 907.49 g/mol is their molecular weight |
| Their solubility is less in polar solvents | Their Solubility is high in polar solvents |
| Their wavelengths are 430-660nm | Their wavelengths are 450-650 nm |
Conclusion
Chlorophyll A and Chlorophyll B are the two main pigments found in plants. They both are of great importance for the plants. Both the pigments vary in their structures and composition. They have a methyl group present, while Chlorophyll B has an aldehyde group attached to its ring.
