Catabolism of proteins, fats, and carbohydrates in the three stages of cellular respiration •Glycolysis - cytosol•Fatty Acid Oxidation: Inner matrix of mitochondria•Citric Acid Cycle: Inner matrix of mitochondria•Oxidative Phosphorylation: Inner membrane of mitochondriaAnimal cellPlant cellMitochondriaRat brain dendrite illustrating 6 mitochondriaglycolysis pyruvate dehydrogenaseglucose pyruvate acetyl-CoACatabolism of proteins, fats, and carbohydrates in the three stages of cellular respiration •Glycolysis - cytosol•Fatty Acid Oxidation: Inner matrix of mitochondria•Citric Acid Cycle: Inner matrix of mitochondria•Oxidative Phosphorylation: Inner membrane of mitochondriaThe Citric Acid Cycle has Eight StepsStep 1: Formation of CitrateStep 2: Formation of Isocitrate via cis-AconitateStep 3: Oxidation of Isocitrate to α-Ketoglutarate and CO2Step 4: Oxidation of α-Ketoglutarate to Succinyl-CoA and CO2Step 5: Conversion of Succinyl-CoA to SuccinateThe Succinyl-CoASynthetase ReactionHigh energy acyl phosphateHigh energy phosphohistidyl residueHigh energy acyl phosphateSuccinyl-CoA Synthetase from E. coliphosphate group on His246coenzyme Apartial positive charges of “power helices” in dark blue and dark brown stabilize phosphohistidyl group.Step 6: Oxidation of Succinate to FumarateMalonate is a strong competitive inhibitor of succinate dehydrogenaseStep 7: Hydration of Fumarate to Malatefumarasetrans configurationcisconfigurationFumarase is highly stereospecificStep 8: Oxidation of Malate to OxaloacetateEach turn of the citric acid cycle produces 3 NADH, 1 FADH, 1 GTP (or ATP), and 2 CO2Keeping track of the carbon atomsFrom oxaloacetate, not acetyl-CoACitrate: A Symmetrical Molecule That Reacts
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