BIOLCHEM 415 1st Edition Lecture 20Outline of Last Lecture I. Introduction to the Citric Acid CycleII. There are 8 enzymatic steps in the CACIII. Regulation of enzymes in CACOutline of Current Lecture IV. An overview of the electron transport chainV. Complexes I-IV and the reactions they catalyzeVI. Reactive oxygen species Current LectureSubstrate Level Phosphorylation- intermediates with high energy phosphate bonds- phosphorylate ADP ATPOxidative Phosphorylation- electrons NADH/FADH2 through electron transport chain- electrochemical gradient- protons forced across the mitochondrial membrane- occurs in the mitochondria- outer membrane permeable, inner not- the greater the inner membrane’s surface area the greater the ATP generation- more complexes where ATP generation can occur- proton gradient powers ATP synthaseElectron carrier Coenzyme QThese 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.- inner mitochondrial membrane- 3 redox states- oxidized, reduced by 1 e-, reduced by 2 e-- hydrophobic tails allows it to transport electronsCofactor Flavin Mononucleotid (FMN)- reduced to FMNH2Hemes use Fe(II) and Fe(III) for electron transferIron-Sulfur centers - transmit electrons - low redox potentialsRedox potentials- related to ΔG°- ΔG° = -RTlnKeq pH=7- ΔG°’ = -nFΔEo’Electron transport- 4 complexes can be transported through- the water fall analogy- electrons move from high potential energy to lower potential energyComplex I : NADH-Q Oxidoreductase- very large- 2 electrons in, 4 H+ out- reduced Q QH2Complex II : Succinate Q Reductase- part of citric acid cycle- 2 electrons from FADH- reduced Q QH2- does NOT pump protonsComplex III : Q-Cytochrome C Oxidoreductase- 4 protons to intermembrane space- catalyzes Q cycle- transfer of 2 e- from QH2 to 2 cytochrome C- cytochrome C : each contains 1 heme that accepted 1 electronComplex IV : Cytochrome C Oxidase- 4 reduced cytochrome C per O2 molecule water- catalyzed by Heme a3 and CuB- for each O2 reduced to 2 H2O 4 H+ pumped and 4 H+ taken- 1 electron per hemeReactive O2 Species and Disease- dangerous side reactions - cellular damage/death- oxidizing proteins/enzymes/etc- contribute to aging- superoxide dismutase (SOD)- eliminates O2- O2 +H2O2- H2O2 H2O and O2- mutation in gene SOD1 linked to Amyotrophic Lateral Sclerosis (ALS)- loss of upper/lower metor protons in
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