Cellular Respiration Chemical Products have a lower How we harvest energy from food Potential Energy than Reactants Todays topics Atoms bonded in • Oxidation and Reduction High Potential Energy • Glycolysis – glucose à pyruvate, ATP, Configuration NADH – in cytoplasm Energy is Released • Mitochondria – Structure and function Atoms bonded in • Citric Acid cycle (if time) Low Potential Energy Configuration 1 October 2021 1 2 If one thing gets oxidized, another Sometimes an electron Is only partially lost or becomes reduced gained Reactants Products becomes oxidized Energy becomes reduced Methane Oxygen Carbon dioxide Water Transfer of electrons from A to B Change in the degree of electron sharing in covalent bonds Oxidation, Reduction, and Energy How is energy harvested upon oxidation? • Direct ATP production – Substrate Level Phosphorylation • Electron Carriers - NAD, NADP, FAD – Can cash in reduced carriers for ATP – Oxidative Phosphorylation 6 1 ATP Electron Carriers Adenine • NAD+ nicotinamide adenine dinucleotide NAD+ + H+ + 2e- -> NADH • NADP+ nicotinamide adenine dinucleotide phosphate NADP+ + H+ + 2e- -> NADPH 3 phosphate groups • FAD flavin adenine dinucleotide Ribose + FAD + 2H + 2e- -> FADH2 8 NAD+/NADH Is an Electron Carrier 15 gallons Of gasoline Many Small Controlled reactions 10 Proteins Carbohydrates Fats Your cells harvest energy from glucose in small steps Amino Sugars Glycerol Fatty Catabolic acids acids Pathways Glycolysis Glucose Glyceraldehyde-3- P NH3 Pyruvate Acetyl CoA Citric acid cycle Oxidative phosphorylation 12 2 Proteins Carbohydrates Fats Amino Sugars Glycerol Fatty General Catabolic Pathway acids acids • Step down the oxidation series of carbon in a series of small Steps Glycolysis Some activation step Glucose Oxidation step, with energy harvest Glyceraldehyde-3- P Reorganization step NH3 Pyruvate Another oxidation step, another harvest Acetyl CoA Another reorganization etc. etc. Citric acid yield product of pathway cycle 13 Oxidative 14 Figure 9.19 phosphorylation Glycolysis: Steps in the oxidation of In Cytoplasm glucose Glucose 6 carbon sugar For each process: Harvest What goes in? In Mitochondrial What comes out? Matrix ATP and NADH Where does it happen? oxidized to pyruvate Keep track of the carbon atoms. (Two) On Inner 3 carbon acids Keep track of the Mitochondrial membrane 15 energy molecules. CH2OH H H H HO H HO OH Glycolysis- H OH Glucose Glycolysis Summary the details ATP 1 Hexokinase ADP CH2OH P Add P (from ATP) H O H H OH H HO Energy Rearrange H OH Glucose-6-phosphate 2 Investment Phosphoglucoisomerase CH2O P O CH2OH H HO HO Stage H HO H Add P (from ATP) Fructose-6-phosphate 3 ATP Phosphofructokinase Energy harvest ADP O CH O CH phase P 2 2 O P HO Energy investment H OH HO H Fructose- phase Split into two 3 carbon 1, 6-bisphosphate 4 2 of Aldolase Do Not Memorize! units these 5 H O P CH2 Isomerase C O Rearrange C O Just notice the CHOH CH2OH CH2 O P Dihydroxyacetone Glyceraldehyde-18 This is the amount of detail you should know sequential changes phosphate 3-phosphate Figure 9.9 A 17 3 Oxidize aldehyde to acid 2 X Glyceraldehyde-3-P6 add another phosphate NADH P i + 2 H+ Harvest NADH 2 P O C O CHOH P CH2 O Make ATP by 1, 3-Bisphosphoglycerate Substrate Level Phosphorylation 7 ATP 2 O– C O Glycolysis CHOH CH2 O P 3-Phosphoglycerate Energy payoff 8 Rearrange this pathway happens 2 O– C O twice for each glucose H C O P CH2OH 2-Phosphoglycerate 9 Enolase 2 H2O Oxidize alcohol to ketone – 2 O C O C O P CH Make ATP by 2 Phosphoenolpyruvate Substrate Level Phosphorylation 10 Do Not Memorize! ATP 2 O– C O Just notice the Pyruvate x2 C O 19 Do Not Memorize! CH3 sequential changes Figure 9.8 B WhatFigure 9.6-3 happens to the products of glycolysis? Electrons Electrons carried carried via NADH and via NADH FADH2 Substrate-level Pyruvate Oxidative Phosphorylation Glycolysis phosphorylation: oxidation Citric acid electron transport Glucose Pyruvate Acetyl CoA cycle and chemiosmosis CYTOSOL MITOCHONDRION ATP ATP ATP Substrate-level Substrate-level Oxidative phosphorylation phosphorylation phosphorylation 21 Proteins Carbohydrates Fats Mitochondrion Amino Sugars Glycerol Fatty acids acids Glycolysis Matrix Glucose Glyceraldehyde-3- P Inner NH Membrane 3 Pyruvate Acetyl CoA Outer Citric Membrane acid cycle Intermembrane 23 Oxidative 24 Space phosphorylation 4 .