Biochem 1000 Chapter 20 Oxidative Phosphorylation Enters from the citric acid cycle First part of the electron transport chain We get our last bit of energy from glucose catabolic NADH FADH2 3 NADH 6 total and 1 FADH2 2 total made in the mitochondria These don t readily give up energy Contribute to the formation of ATP ELECTRON TRANSPORT CHAIN DOES NOT MAKE ATP respiration Chemiosmosis and the Electron Transport Chain coupled together I REDOX RXNS e transfer The ETC is essentially a chain of redox reactions A reduced product is actually the oxidizing agent and the oxidized product is the reducing agent A Measure affinity for e higher affinity accepts electrons One reaction gives up one accepts The compound with the E0 redox potential reduction potential measure of a molecules tendency to donate and accepts electrons negative E0 strong reducing agent positive E0 strong oxidizing agent First you need to determine which is the more positive half reaction standard reduction potential reduction potential under standard conditions actual reduction potential reduction potential under actual conditions These are not equal to each other Nerst equation E0 RT nF ln oxidized reduced B Comparing and Determining Direction of e Flow Spontaneous O2 2 H 2e H2O NADH NAD O2 NADH H2O NAD H 2e E 0 0 82 V E 0 0 32 V E 0 1 14 V Ex C Determining G from G nF Electron Transport Chain ETC 2 separate systems I INTRO II LOCATION IN MITO Endosymbiosis Theory III STEPS OF ETC A Complex I NADH Q oxidoreductase redox centers a flavin mononucleotide FMN b Fe S clusters 6 8 Cmplx I is a proton H pump ubiquinone B Complex II succinate Q reductase FAD coenzyme redox centers a Fe S clusters ubiquinone C Complex III Q cytochrome c oxidoreductase redox centers a hemes in cytochrome proteins b Fe S cluster 1 cytochrome c Complex IV Cytochrome c oxidase redox centers a heme groups b Cu ions Toxic Derivatives
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