Photosynthesis Chlorophyll wavelength absorption

In summary, the chlorophyll in land plants primarily absorb blue and red wavelengths of light because that is the mechanism that has evolved for photosynthesis. The total energy of the light is not as important as whether a single photon has enough energy to cause ionization, and it takes four photons to trigger a reaction. This system is complex and has only evolved once in nature, suggesting its efficiency and effectiveness. Using lower-energy photons may not result in a sufficient charge separation for the reaction to occur.
  • #1
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Why do the chlorophyll in land plants absorb primarily in the blue and red wavelengths, http://en.wikipedia.org/wiki/File:Solar_Spectrum.png" [Broken]? Isn't more energy available in 500nm green light vs 700nm red light? [tex]E =\frac{hc}{\lambda}[/tex]
 
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  • #2
I suppose the only answer possible is "Because the mechanism that was evolved requires it."

Total energy is less important here than whether a single photon has sufficient energy to cause the ionization/charge-separation which is the first step in photosynthesis.
And that single photon doesn't have enough energy in itself either; it takes four photons to cause a reaction, while the energy is 'stored' in the manganese ion cluster of Photosystem II.

It's all a very intricate system, and it's somewhat telling that nature has only evolved this once; it's essentially the same PS2 in all green things.

Perhaps, for instance, a lower-energy photon would not cause a large enough charge separation, and the electron would too easily return back to the chlorophyll.
 

What is photosynthesis?

Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy. This process involves the absorption of light by chlorophyll, which is used to produce glucose and oxygen.

What is chlorophyll?

Chlorophyll is a green pigment found in the chloroplasts of plants and algae. It is responsible for absorbing light energy during photosynthesis and is essential for the process to occur.

What wavelengths of light does chlorophyll absorb?

Chlorophyll primarily absorbs red and blue wavelengths of light, while reflecting green wavelengths, which gives plants their green color. This is why plants appear green to the human eye.

Why is chlorophyll important for photosynthesis?

Chlorophyll is essential for photosynthesis because it is responsible for capturing and absorbing light energy. Without chlorophyll, plants would not be able to convert light energy into chemical energy and produce glucose, which is necessary for their growth and survival.

How does the absorption of light by chlorophyll impact photosynthesis?

The absorption of light by chlorophyll is crucial for photosynthesis to occur. The absorbed light energy is used to power the chemical reactions that convert carbon dioxide and water into glucose and oxygen. Without the absorption of light by chlorophyll, photosynthesis cannot take place.

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