Photophosphorylation

Photophosphorylation

• Photon of light enters photo system II and works its way to reaction center
• Electron is excited in RC and moves to acceptor with high energy (chlorophyll is photoactivated)
• Electron moves across proton pump and gives up energy for active transport
• Photon enters reaction center in PS I
• Electrons excite and move to acceptor with high energy
• Electron moves to NADP Reductase
• Gives energy to reduce NADP+
• High concentration of H+ inside thylakoid space
• H+ give energy for chemiosmosis
• Water is split by photolysis releasing two H+ and two electrons; water is a by product

Non-cyclic

• If NADP Reductase can accept electron and so water is split
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Cyclic

• If NADP cannot accept electron it cycles back to electron acceptor in PS II
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