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Review 3: Metabolism-Respiration & Photosynthesis. AP Biology. Respiration & Photosynthesis. Energy production through chemiosmosis Coupled reactions get the work done Respiration Photosynthesis Regulation of metabolism is through negative feedback of enzyme pathways.
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Review 3: Metabolism-Respiration & Photosynthesis AP Biology
Respiration & Photosynthesis • Energy production through chemiosmosis • Coupled reactions get the work done • Respiration • Photosynthesis • Regulation of metabolism is through negative feedback of enzyme pathways
Energy Production through Chemiosmosis • Chemiosmosis • -Coupling of the proton pump to ATP synthesis • -Responsible for almost all of the ATP produced from food & • all of the ATP produced from photosynthesis
Chemiosmosis • Pumping of H+ ions onto one side of a membrane through protein pumps in an Electron Transport Chain (ETC) • Flow of H+ ions across a membrane down the concentration gradient through ATP synthase
Coupled Reactions Get the Work Done • Oxidation & Reduction • ETC & pumping of H+ (protons)
Oxidation & Reduction • Oxidation – loss of an electron • Reduction – gain of an electron • ALWAYS TAKE PLACE TOGETHER!!!
Respiration • Mitochondria • Anaerobic: glycolysis, fermentation
Mitochondria • ETC in inner membrane: Cristae increase surface area • H+ ions concentrated in intermembrane space & flows into matrix through ATP synthase • Oxidative phosphorylation: O2 final electron acceptor + NAH/FADH to donate electron • Kreb’s cycle produces electron carriers: NADH, FADH • High ATP production (~36 ATP)
ATP Synthase • General term for an enzyme that can synthesize ATP from ADP and inorganic phosphate by using energy • ADP + Pi → ATP
Oxidative Phosphorylation • Metabolic pathway that uses energy released by oxidation of nutrients to produce ATP
Kreb’s Cycle • Occurs in matrix of mitochondrion • Generates 2 ATP per molecule of glucose • Produces electron carriers: NADH, FADH
Anaerobic Respiration • Inorganic molecule other than oxygen accepts the hydrogen • Low ATP production (~2 ATP) • Glycolysis • -Converts glucose into pyruvate • -Free energy released is used to form ATP & NADH • -In the absence of oxygen, cells must rely on glycolysis to produce ATP. • Fermentation • -Organic molecule accepts the hydrogen atom generated by glycolysis
Photosynthesis • Chloroplasts • Calvin cycle • C4 & CAM plants
Chloroplasts • H+ ion concentration in inner thylakoid space & flows out into stroma • Phosphorylation: light energy + splitting of water to donate electron • Light dependent reactions: Photosystem II (produces ATP) & Photosystem I (produces NADPH)
Light Dependent Reactions • Photosystem II: 1st protein complex, In thylakoid membrane, produces ATP • Photosystem I: produces NADPH
Calvin Cycle • 3rd stage of photosynthesis • Formation of organic molecules from atmospheric CO2 • May occur in absence of light as long as ATP & NADPH are available • Light independent reaction • Carbon fixation through RuBisCo enzyme • Use ATP & NADPH from light reactions to produce 3C sugars
C4 & CAM Plants • Adaptation in hot, dry ecosystems because stomates close a lot • Reduce photorespiration: Low carbon fixation in a high oxygen/low CO2 • Regulation of metabolism is through negative feedback of enzyme pathways.