Chapter 9 Cell Respiration Part 1 Pages 164 172 Redox Reactions Glycolysis Review Delta G Change in free energy available in the products vs the free energy available in the reactants Exergonic vs Endergonic Exer negative DeltaG Ender positive DeltaG Anabolic Vs Catabolic Cat Breaks down Anabolic Builds up molecules Metabolic Equilibrium Products become reactants in next rxn never reaches equilibrium Energy Coupling Coupling an exergonic and endergonic reactions Redox Reactions How does the breakdown of glucose yield ATP Oxidation Loss systematic remocal of electrons or loss of electrons OIL Oxidation Is Loss Reduciton Gain addition of electrons reduces overall charge RIG Reduction is Gain Electronegativity attraction of an atom for the electrons of a covalent bond Xe Y X YeX becomes oxidized Y Becomes reduced NaCl Na Cl2O2 CH4 CO2 2H2O Oxygen is reduced because in the water the oxygen has gained control of the majority of the electrongs 6O2 C6H12O6 6CO2 6H2O How do you get energy from Redox reactions 1 Organic fuels broken down in series of steps 2 Electrons e stripped in stages 3 Controlled release of energy 4 ATP formed via phosphorylation a Substrate level Enzymatic transfer to ADP b Oxidative series of e acceptors to O2 How do you systematically remove e 1 Dehydrogenase enzyme removes pairs of hydrogen atoms a Written as 2H 2eb 1H 2e delivered to coenzyme 1 H to cytosol 2 NAD Nicotinamide adenine dinucleotide a coenzyme e shuttle acceptor allows controlled release of energy Calculate of moles of ATP generated from oxidation of 1 mole of NADH In theory 52 6 7 3 7 2 moles ATP In reality 3 moles ATP Why Electron Transport chains allow for a controlled release of energy Catabolic Pathways yield energy Many small steps trap electrons Electrons are transferred to O2 via Electron Transport Chain Controlled release yields o ATP o HEAT Overview of Cellular Respirations 1 Breakdown fuel to monomers 2 Glycolysis Breakdown glucose to 2 pyruvate a Form NADH ATP b Location Cytosol of the cell 3 Citric Acid Cycle Pyruvate to CO2 a Form NADH ATP FADH2 b Location Mitochondrial Matrix 4 Oxidative Phosphorylation E transport chain takes e from shuttles NADH FADH2 a Form O2 H2O lots of ATP b Location Inner Membrane of mitochondria i Citric Acid cycle occurs in the Matrix ii Electron Transport chain occurs in the inner membrane Kinase enzymes that transfer phosphate groups Why is this useful Isomerase Enzymes catalyzes reversible reaction But Metabolic Disequilibrium occurs DHAP G3P Both are isomers K1 Review Quiz What do you need to remove pairs of e Dehydrogenase Enzyme and NAD What are the net products of glycolysis 2 Pyruvate 2 ATP 2 NADH 2 H2O Name 3 enzymes and 4 substrates you need to know from glycolysis Enzymes Kinase Isomerase Dehydrogenase Substrates Glucose pyruvate G3P DHAP Pg 169 Dehydrogenase enzyme That removes hydrogen to NAD Substrate level Phosphorylation Glycolysis happens in the cytosol If oxygen is not present fermentation occurs Ethanol or lactate If oxygen is present aerobic respiration occurs in the mitochondria In the mitochondria there are a series of reactions called the junction reactions W O2 pyruvate transported to mitochondria matrix Enzyme complex pyruvate dehydrogenase catalyzes Decarboxylation of pyruvate lose 1 Co2 2 C compound oxidized to form acetate 2e NADH Acetate binds to coenzyme A acetylCoA Overview of Citric Acid Cycle 1 What does cycle mean 1 Start at one point and through a series of reactions gets back to the starting molecule 2 What is the carbon input Output Follow pink blue C 1 3 What is the energy payoff 4 Fig in book accounts for only 1 pyruvate not 2 Citric Acid Cycle Tricarboxylic acid cycle Kreb s cycle Addition Phase 2C 4C 6c Acetyl CoA which has 2 carbons Oxaloacetate the starting molecule Which has 4 carbons Citrate molecule 6 carbons Removal Phase Loss of 2 C to 2 CO2 Decarboxylation 2 pair e removed to 2 NADH Dehydrogenase Regeneration Phase CoA displaced by Pi Pi removed to GTP then ATP substrate level phosphorylation One pair e removed to form FADH2 Dehydrogenase One pair e removed to form NADH Dehydrogenase At this point we have harvested all of the carbons from glucose and the eOxygen is left to be dealt with Mitochondrial Structure Oxidative phosphorylation 1 Electron transport chain fig 9 13 a Located in inner mitochondrial membrane b Composed of 4 multiprotein complexes i w cofactors 1 Fe S complex OR 2 Heme Fe groups c E transferred to cofactors via series of redox rxns d O2 final e acceptor H2O e Overall drop DeltaG from i NADH to 53 kcal mol ii FADH2 40 kcal mol f Many poisons toxins target these proteins 2 Chemiosmosis Movement of protons a Flow from H from high low used to drive all work b H pumped from matrix to intermembrane by rensmembrane proteins of ETC c Creates potential energy 3 ATP Synthase Fig 9 14 a Powered by H gradient b Multiple proteins stator channel rotor rod knob c H flow thru stator rotor turns rod activates catalytic sites on knob ATP formed How much energy ATP was harvested from glucose Given yields NADH 2 5 ATP FADH2 1 5 ATP Glycolysis 2 ATP invest 4 ATP produce 2 ATP substrate 2 NADH X 2 5 ATP NADH 5 ATP oxidative Junction Reactions 2 pyruvate X 1 NADH X 2 5 ATP NADH 5 ATP oxidative Citric Acid Cycle 2 pyruvate X 1 ATP 2 ATP Substrate 2 pyruvate X 3 NADH X 2 5 ATP NADH 15 ATP Oxidative 2 pyruvate X 1 FADH2 X 1 5 ATP FADH2 3 ATP Oxidative Total of 32 ATP How efficient is this process Burn Glucose DeltaG 686 kcal mol Systematic Release 32 moles ATP Yield Actual Theoretical o Theoetical 686 kcal mol o Actual 233 6 kcal mol o Answer is 34 Fermentation Energy harves w o O2 or electron transport Glycolysis plus regenerate NAD Occurs in o Bacteria yeast produce CO2 ethanol o Other bacteria fungi muscle lactate Why do we need to regenerate NAD o Glycolysis wouldn t be able to continue because it is a cycle How efficient is this process 2 ATP