BIOL 1361 1nd Edition Lecture 17Outline of Last Lecture I. ATPII. Free Energy of ATPIII. Chemical Work: Anabolic Reactions Building MoleculesIV. Transport Work and Mechanical WorkV. ATP RecyclingVI. Photosynthetic OrganismsVII. ChloroplastsVIII. Summary EquationIX. Two Stages of PhotosynthesisX. Light ReactionsXI. Engelmann’s Experiment 1833Outline of Current LectureI. ReactionsII. Figure 8.13III. Calvin CycleIV. Phase 1: Carbon FixationV. Phase 2: ReductionVI. Phase 3: Regeneration of the (5) Carbon RuBPThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Current LectureI. Reactionsa. Occur in photosystem II and photosystem Ib. Photosystem = complex of protein and chlorophylli. In thylakoid membraneii. Many photosystems per chloroplastc. Light Reactions – Figure 8.13II. Figure 8.13a. 1. Electron Excitationi. Chlorophyll in PSII absorbs photonsii. Electrons of chlorophyll boosted into a higher energy orbitalb. 2. Electron Capture: Excited electron passed to primary electron acceptorc. 3. Electron Replacement: PSII splits wateri. H2O 2e- + 2H+ + ½ O2ii. ½ O2 + ½ O2 O2iii. O2 diffuses out of leafiv. Electrons taken from H2O replace electrons taken from reaction center chlorophyll molecules (P680) by primary acceptord. 4. Electron Transporti. H+ from H2O released into thylakoid spaceii. Electron passed from primary acceptor in PSII to electron transport chaine. 5. ATP is producedi. Details of ATP production in the thylakoid (Fig 8.16)ii. H+ pumped from stroma into thylakoid spaceiii. [H+] high inside thylakoid, lower outsideiv. H+ flows down concentration gradient through ATP synthasef. 6. PS1 chlorophyll absorbs photons i. Excited chlorophyll electrons passed to reaction center complex and to primary acceptorg. 7. Excited electrons passed down 2nd electron transport chain i. Electrons donated to NADP+ NADPHh. 8. NADPH carries electrons needed for sugar synthesisIII. Calvin Cycle (Fig 8.17)a. Uses ATP and NADPH to fix carbonb. Occurs in chloroplast stromaIV. Phase 1: Carbon Fixationa. Start with 5 Carbon sugari. Called… Ribulose bisphosphate = RuBPb. Enzyme adds (1) CO2 to a 5C sugar 6C sugarc. 6 Carbon sugar split into (2) 3 C-PO4 moleculesV. Phase 2: Reductiona. Biphosphate 3 Carbon molecule receives 2 electrons from NADPHb. Loses (1) PO4c. G3P – glyceraldehyde-3-phosphateVI. Phase 3: Regeneration of the (5) Carbon RuBPa. (5) molecules of 3 Carbon G3P rearranged into (3) molecules of 5 Carbon RuBP toaccept CO2
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