#5: Pathway of Photosynthesis Flashcards Preview

Bio 4U- Unit 2: Photosynthesis > #5: Pathway of Photosynthesis > Flashcards

Flashcards in #5: Pathway of Photosynthesis Deck (4)
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1. Photosystem II –P680

- Oxidizes (splits) water into electrons, protons, and oxygen gas (released for us!)
- Photon of light excites P680*, releasing an electron to primary acceptor and creating P680+
- P680 is highly electronegative and water is oxidized leaving H+ and oxygen gas


2. Cytochrome complex

- PQ (protein) receives electron from primary acceptor and moves to “cytochrome complex”
- Energy carried in electron moves another H+ into the thylakoid


3. Photosystem I – P700

- From the cytochrome complex energy is nearly gone and a second photon is used to provide more energy
- This high energy electron is transferred along the chain and used to reduce NADP+ to NADPH (through NADP reductase)


4. Proton Gradient
- 3 ways

Photosystem I, cytochrome complex (PQ), Photosystem II create a proton gradient across the thylakoid membrane in 3 ways:

1. Oxidation of water
2. Carrying protons across with PQ
3. Removal of protons from the stroma during reduction NADP+