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PhotosynthesisPhotosynthesisPowerPoint PresentationSlide 4Slide 5Slide 6Slide 7PlantsSlide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15ChloroplastsSlide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Photosynthesis - the reactionSlide 29Slide 30Light reactionsSlide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Calvin cycleSlide 45Slide 46Slide 47Slide 48Slide 49Slide 50Slide 51Slide 52Slide 53Slide 54Slide 55Slide 56PhotosynthesisChapter 7Photosynthesis •Solar energy to carbohydrate– Carbs from photosynthesis used by every living thing on earth•Producers–Plants– Algae– Cyanobacteria•ConsumersPlants •All green portions of plants•Leaves–Surface area–Mesophyll section is photosynthetic sectionPlants •Chlorophyll captures solar energy - •Water - roots•Carbon dioxide - stomata•All materials to chloroplastsChloroplasts •Double membrane•Stroma - fluid with enzymes–Reduces carbon dioxide•Thylakoids - sacs–Captures solar energy - chlorophyll•Granum - stacks•Thylakoid spaces are connectedChloroplasts •Thylakoids capture solar energy that drives rxn•Rxn occurs in stroma–Carbon dioxide -> carbohydrate–Produces enough to provide energy for plant and othersPhotosynthesis •Pigments - absorb portions of the visible light spectrum–Chlorophyll a–Chlorophyll b–CarotenoidsPhotosynthesis - the reaction•Solar energy + CO2 + 2H2O -> (CH2O) + H2O + O2•Solar energy + 6CO2 + 6H2O -> (C6H12O6) + 6O2Photosynthesis - the reaction•Redox rxn•CO2 -> CH2O = reduction•H2O -> O2 = oxidationPhotosynthesis - the reaction•Light reactions– Thylakoid membrane– Absorbs solar energy–Energizes electrons– Electron transport system•Calvin cycle reaction– Stroma–CO2 reducedLight reactions•Noncyclic electron pathway–Electrons flow from water to NADPH•Nicotinamide adenine dinucleotide phosphate–Photosystems•Pigment complex–Pigments + electron acceptors•Photosystem II•Photosystem ILight reactions•PS II –Pigments - antennae–Chlorophyll b–Carotenoids –Chlorophyll a - reaction center–Increased energy when electron arrives at rc–Electron from oxidation of waterLight reactions•PS II – Water split by enzymes– Enzyme connected to rc–Releases electrons one at a time– Oxygen released to atmosphere– 2H+ stay in thylakoid spaceLight reactions• PS II –Electron transport system–Receptor molecules - Pass e from molecule to molecule•Quinone•Proton pump (complex)– Pumps proton into thylakoid space for ATP synthesis•Plastocyanin (protein)•PS ILight reactions•ATP chemiosmosis–Protons from water and proton pump (from stroma) in thylakoid space–Thylakoid membrane impermeable to protons–Pumped across membrane by ATP synthase•What kind of molecule is ATP synthase–As it proton passes through, ADP in stroma is phosphorylated = ATPLight reactions•PS I–Complex–13 protein subunits - center–130 chlorophyll a - antenna–E Passed to more acceptors–To NADP+–Accepts 2 e and one H•NADP reductase–NADPHLight reactions•Cyclic reactions–From PS I to PS I–Produces more ATP–Electron shuttled to proton pump–Does not make NADPH–Plants need more ATP than NADPH–Depends of needCalvin cycle•Energy from ATP from light rxns•Reduction possible from NADPH•Carbon fixation•Carbon dioxide reduction•Regeneration of RuBP–Ribulose 1, 5-bisphosphateCalvin cycle•Carbon dioxide fixation–CO2 + RuBP (five carbon molecule) -> 6 carbon molecule -> 2 three C molecules•Phosphoglycerate (PGA)–Enzyme - RuBP carboxylase (rubisco)•Slow•50% of protein in most plants•Most abundant protein on earthCalvin cycle•Reduction of carbon dioxide–Each PGA reduced to PGAL (G3P)–NADPH donates electrons–ATP provides energy–R-CO2 -> R-CH2O (carb)–Enzymes•PGA kinase•G3P dehydrogenaseCalvin cycle•Regeneration of RuBP–Takes three turns of cycle for one PGAL (G3P) to be released–For every 1 released, 5 go to the regeneration of 3 RuBP–Also costs ATP–5 PGAL -> 3 RuBP–Released PGAL (G3P) used for many thingsCalvin cycle•Overall reaction•3CO2 + 9ATP + 6NADPH + water -> G3P (glyceraldehyde 3-phosphate) + 8P + 9ADP + 6NADP+Calvin cycle•PGAL (G3P)–Glucose–Sucrose–Starch, cellulose–Fatty acids, glycerol–Amino

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NU BIOL 1101 - Photosynthesis

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