Photophosphorylation

Photophosphorylation is the process of converting light energy into chemical energy in the form of ATP (adenosine triphosphate) during photosynthesis. This process occurs in the thylakoid membranes of the chloroplasts in photosynthetic organisms. Photophosphorylation is a vital step in the photosynthesis process, as it provides the energy required for the synthesis of glucose.

Process

Photophosphorylation involves two different mechanisms: cyclic and non-cyclic photophosphorylation.

Cyclic Photophosphorylation

In cyclic photophosphorylation, the electron released from the photosystem is returned to it after passing through the electron transport chain. This process only involves photosystem I and produces ATP but not NADPH.

Non-Cyclic Photophosphorylation

In non-cyclic photophosphorylation, the electrons are not returned to the photosystem. Instead, they are used to reduce NADP+ to NADPH. This process involves both photosystem I and II and produces both ATP and NADPH.

Role in Photosynthesis

Photophosphorylation plays a crucial role in the light-dependent reactions of photosynthesis. The ATP and NADPH produced during photophosphorylation are used in the Calvin cycle to convert carbon dioxide into glucose.

See Also

• Photosynthesis
• Chloroplast
• ATP
• NADPH
• Calvin cycle

References

Photophosphorylation Resources
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