Biology Education

Difference between Chlorophyll A, B and Photosynthesis

Main Difference

Both chlorophyll A and B are essential for photosynthesis but chlorophyll A plays major role then chlorophyll B.Chlorophyll A has large molecules while chlorophyll B has smaller.

Chlorophyll A

chlorophyll-aIn the oxygenic part of photosynthesis chlorophyll A is used exclusively. The light part of wavelength violet and red are mostly absorbed in this process. Green light is reflected thus we see plants green. In electron transport chain, the chlorophyll is responsible to donate primary electron. Thus, it is essential for photosynthesis in eukaryocyte, cynobacterium, and prochlorophyte. In the antenna complex the chlorophyll transfers energy and ends the reaction center where p680 and p700 are located. It is not the only property to use in photosynthesis but it is essential one to release chemical energy. In anaerobic autotroph and bacteria little amount of chlorophyll A is found.

Chlorophyll B

chlorophyll-bOne more form of chlorophyll is chlorophyll B. It also is in charge to lock in light energy from the sun may also be termed as photoreceptor. It is additional soluble than chlorophyll A, for the reason that it has carbonyl group, in polar solvents. It on the whole absorbs blue light and reflects yellow wavelength light. Thus it appears yellow. Around the photosystem 2, the light harvesting antenna, it is highly surrounded by chlorophyll B. shade adapted chloroplast has higher ratio of photosystem 2 to 1. Due to this the chlorophyll B ratio is higher and chlorophyll A is lesser. This is an adaptive change. By shade chloroplast the chlorophyll B increases the range of absorbed light wave length. It occurs side by side to chlorophyll A but it is an accessory chloroplast. The perks of it is that it acts as an emergent backup. It has molecular weight of 907. Chlorophyll B has difference in its function group bind to the porphyrin that makes it stand out in photosystem. It primarily absorbs red and blue light from the sun. It also plays role to synthesize glucose in plant.


photosynthesisWhen light energy is utilized with carbon dioxide to form chemical energy to form sugar and water is called photosynthesis. The reaction can be mentioned by saying that it is responsible to yield glucose and oxygen by carbon dioxide and water. To complete this reaction to the fullest, light energy from the sun and chlorophyll in a plant plays a major role. There are two basic parts of photosynthesis, one is light cycle and the other is Calvin cycle. It works in this way that when light strikes the green plant the chlorophyll molecules get excited and release some ions to leave the molecules. Light also split water into its compounds that is oxygen and hydrogen. Oxygen as waste leaves the plant. The electrons in hydrogen create ATP and NADPH. Two energy packets thus it is said that light energy is turned into chemical energy. In Calvin cycle, these products of light reaction incorporate carbon dioxide and fix it to produce a glucose molecule. Photosynthesis marks the importance of plants by making them the most primary in the food chain. Even the waste product, oxygen, is very important for lives of human being.

Key Differences

  • Both chlorophyll A and B are essential for photosynthesis but chlorophyll A plays major role then chlorophyll B.
  • Chlorophyll A is a principal pigment while chlorophyll B is accessory pigment.
  • Formula of chlorophyll A is C55H77O5N4 while formula of chlorophyll B is C55H70O6N4
  • 873 is molecular weight of chlorophyll A while 907 is molecular weight of chlorophyll B.
  • Chlorophyll A has large molecules while chlorophyll B has smaller.
  • The ratio of chlorophyll A: B is 3:1.

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