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CellularRespira,onIII Oxida&vePhosphoryla&on Glycolysis Summary Today sTopics: • ReviewGlycolysisand CitricAcidCycle • Oxida,ve Phosphoryla,on – ElectronTransport (oxida,onphase) – ATPSynthesis (phosphoryla,onphase) 6-Carbon Sugar --> 2x 3-Carbon Acids http://www.biologie.uni-osnabrueck.de/biophysik/Feniouk/images/wm1.jpg • Fermenta,on October 12, 2016 2 Overview of Citric Acid Cycle Cytoplasm Net Result of Glucose Catabolism • Glycolysis – #ATP: – #electroncarriers: • Pyruvateoxida,ontoacetyl-CoA Matrix of Mitochondria – #ATP: – #electroncarriers: • Citricacidcycle: – #ATP: – #electroncarriers: 3 4 Electron Transport Chain produces a proton gradient ElectronTransprort • OxidizesNADHand FADH2backtoNAD+ andFAD • Electronsgivento theelectron transportchain Released energy used to make ATP • Eventuallye-andH+ giventoOxygento formWater 6 1 1.TheOxida,vepart Oxida,onofNADH andFADH2 Glycolysis Citirc acid cycle ATP ATP Oxidative phosphorylation ATP • 3protonpumping stepsfromNADH oxida,on Outer mitochondrial membrane Inner mitochondrial membrane • Only2proton pumpingstepsfrom FADH2oxida,on Matrix Free energy (G) relative to O2 (kcl/mol) NADH Cytoplasm 50 FADH2 40 I FMN Fe•S FAD II Fe•S O III Cyt b 30 Fe•S Cyt c1 IV Cyt c Cyt a Cyt a3 20 10 2 H + + 1⁄2 O2 0 4 H + O2 = 2 H2O + energy H 2O WhatgoodistheH+gradient? ProtongradientdrivesATPsynthesis ++++++++++++++++++++ Intermembrane Space Proton motive force due to Charge gradient Matrix Space ---------------------------- H+ H+ H+ H+ H+ H + H+ H+ H+ H+ H+ H+ Intermembrane Space pH 6 Proton motive force due to Concentration Gradient Matrix Space H+ H+ H+ H+ pH 8 H+ Stores energy that can do work! LifeWithoutOxygen 2. The phosphorylation part ATP synthase CYTOSOL Electron shuttles span membrane MITOCHONDRION 2 NADH or 2 FADH2 2 NADH 2 NADH Glycolysis Glucose 2 Pyruvate 2 Acetyl CoA + 2 ATP by substrate-level phosphorylation Maximum per glucose: That proton gradient is used to power ATP synthesis 6 NADH Citric acid cycle 2 FADH2 Oxidative phosphorylation: electron transport and chemiosmosis + 2 ATP + about 32 or 34 ATP by substrate-level by oxidative phosphorylation, depending phosphorylation on which shuttle transports electrons from NADH in cytosol About 36 or 38 ATP 2 LifeWithoutOxygen LifeWithoutOxygen Glucose • yeast CYTOSOL Pyruvate No O2 present Fermentation yeast O2 present Cellular respiration MITOCHONDRION Ethanol or lactate Acetyl CoA Citric acid cycle muscles Thecontrolof cellular respira,on LifeWithout Oxygen LifeWithout Oxygen • Lac,cAcid fermenta,on • muscles • Ethanol fermenta,on • yeast Glucose AMP Glycolysis Fructose-6-phosphate – Inhibits Stimulates + Phosphofructokinase – Fructose-1,6-bisphosphate Inhibits Citrate Acetyl CoA Citric acid cycle Oxidative phosphorylation Amino acids Fats Carbohydrates Sugars Glycerol Fatty acids Glycolysis Glucose Glyceraldehyde-3- P NH3 Pyruvate ATP Proteins Catabolism vs Anabolism vs Digestion Pyruvate Acetyl CoA Citric acid cycle Oxidative phosphorylation 18 3