15 Photosystem II Photosystem I 4 Photons 4 Photons Electron tra nsport chain

15 photosystem ii photosystem i 4 photons 4 photons

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Figure 10.15 Photosystem II Photosystem I 4 Photons 4 Photons Electron tra nsport chain produced via proton-motive force Energy of electron Higher Lower Figure 10.15 The Z-Scheme Model Links Photosystems II and I.
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How does ATP get produced by the photosystems
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The Enhancement Effect The Z scheme explains the enhancement effect Photosynthesis is more efficient when Both 680-nm and 700-nm wavelengths are available Allowing both photosystems to run at maximum rates Photosystem I occasionally transfers electrons to photosystem II’s electron transport chain to Increase ATP production Instead of using the electrons to reduce NADP
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The Enhancement Effect This cyclic photophosphorylation Coexists with the Z scheme Produces additional ATP
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Figure 10.16 Chloroplast stroma Thylakoid lumen Antenna complex Photosystem II Photosystem I Cytochrome complex ATP synthase Proton- motive force NADP reductase Photon Photon Most abundant in membranes of grana Most abundant in membranes exterior to grana Figure 10.16 Electrons Are Passed from Water to NADP + in a Linear Pathway.
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Figure 10.17 Energy of electron Higher Lower 2 Photons produced via proton-motive force Photosystem I Figure 10.17 Cyclic Electron Flow Leads to ATP Production.
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The Location of Photosystem I and Photosystem II Photosystem II is much more abundant in the interior, stacked membranes of grana Photosystem I and ATP synthase are much more common in the exterior, unstacked membranes The stroma Is the site of ATP production Where the proton gradient established by PS II drives protons
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The Calvin Cycle and Carbon Fixation Two separate but linked processes in photosynthesis: 1.The energy transformation of the light- dependent reactions 2.The carbon dioxide reduction of the Calvin cycle In the presence of light ATP and NADPH are produced by photosystems I and II
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The reactions that produce sugar from carbon dioxide in the Calvin cycle are light- independent Require the ATP and NADPH Produced by the light-dependent reactions The Calvin Cycle and Carbon Fixation
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The Calvin Cycle The Calvin cycle has three phases: 1. Fixation : CO 2 reacts with ribulose bisphosphate (RuBP) Produces two 3-phosphoglycerate molecules Attachment of CO 2 to an organic compound is carbon fixation 2. Reduction : The 3-phosphoglycerate molecules are: Phosphorylated by ATP Reduced by NADPH Producing glyceraldehyde 3-phosphate (G3P) 3. Regeneration : The remaining G3P is used in reactions that regenerate RuBP
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The Calvin Cycle This cycle of reactions occurs in the chloroplast’s stroma One turn of the Calvin cycle fixes one molecule of CO 2 3 turns of the Calvin cycle are required To produce 1 molecule of G3P The discovery of the Calvin cycle clarified How the ATP and NADPH produced by light- capturing reactions Allow cells to reduce CO 2 to carbohydrate
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Figure 10.19 (a) The Calvin cycle has three phases.
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