BRAINCAKECyclic Photophosphorylation
Cyclic photophosphorylation is a pathway of electron flow in the light-dependent reactions that involves only photosystem I.
1. Light is absorbed by photosystem I and excites electrons in its reaction centre chlorophyll.
2. The excited electrons pass to an electron acceptor.
3. Instead of being used to reduce NADP, they pass back along an electron transport chain to photosystem I, losing energy at each carrier.
4. The energy released pumps protons into the thylakoid space, and ATP is made by chemiosmosis as the protons flow back through ATP synthase.
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Key terms in this lesson
- nadp
- A coenzyme that acts as a hydrogen acceptor in the light-dependent reactions of photosynthesis, becoming reduced NADP when it accepts hydrogen.
More in Photosynthesis
- Absorption Spectrum Chlorophyll
- Chromatography
- Photosystems
- The Light-Dependent Reactions
- Non-Cyclic Photophosphorylation
- The Light-Independent Stage
- The Calvin Cycle
- The Products of Photosynthesis
All 20 lessons in Photosynthesis · All Edexcel A-level Biology topics