BIOL 1000 Lecture 4: Photosynthesis
21 Feb 2019
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Document Summary
Chlorophyll a blue-green primary photosynthetic pigment. Chlorophyll b green-yellow secondary photosynthetic pigment. Cartenoids yellow-orange protect plant from uv radiation. Xanthophylls yellow protect plant from uv radiation. Anthocyanins red, violet-blue protect from uv radiation. Structure of chlorophyll: phorphyrin ring absorbs energy, phytotail hydrophobic, anchored in membrane of chloroplast. Stage 1: photoexcitation: accessory pigments (antenna complex) are hit with photons, energy is transferred to the reaction center (chlorophyll a), phenophytin (primary electron acceptor) takes the electrons away from chlorophyll a. The electrons need to be replaced so the z protein accomplishes that: breaks down h2o. Photophosphorylation: the light dependent formation of atp by chemiosmosis is photosynthesis. Differences from non-cyclic: cyclic is a cycle whereas non-cyclic is directional, doesn"t use cyclic nadp reductase, nadph is not created, no need for h2o to replace electrons, no need for psii. Phase 1: carbon fixation: 3 rubp (rubisco 1,5 bisphosphate) combines with 3co2, results in 6 3pg/pga (3-phosphoglycerate, 6atp phosphorylate 6pga (3-phosphoglycerate)
