L14 - Electron Transport and Oxidative Phosphorylation...

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Unformatted text preview: Electron Transport and Oxidative Phosphorylation Topics Electron Transport & Oxidative Phosphorylation The Chemiosmotic Theory Electron Carriers (FeS, hemes & cytochromes) Hydrogen Carriers (flavins & quinones) Membrane Organizationthe Electron Transport Chain Proton Motive Force ATPase Structure and Function Oxidative versus Substrate Level Phosphorylation 1 The Important (Exam) Stuff Explain the Chemiosmotic Theory and how it developed. Define scientific theory and hypothesis. Describe the hydrogen and electron carriers of the Electron Transport Chain. Describe electron transport chain flow from NADH to O . Explain how Proton Motive Force works and 2 ATPase structure and function. Compare ATP production by substratelevel phosphorylation versus oxidative phosphorylation for a glucose molecule. Back to the Map Glycolysis Krebs Cycle Fermentation ETC NADH ATP Carbon Flow 2 Linking Redox reactions and ATP formation Electron Transport Chain Oxidation of NADH (or the + regeneration of NAD ) Electrons transferred to an acceptor via electron carriers Concurrent proton (H+) translocation Oxidative Phosphorylation 2nd mechanism to generate ATP Requires proton gradient Theory & Hypothesis The word theory is used in common speech synonymous with the word idea. Example: "I've got a theory about who committed the murder." Scientists (particularly Einstein) introduced the term Theory defined as A framework of principles derived from objective experimentation explaining important scientific phenomena while allowing for new inquiry and subsequent addition/modification to the principles. Examples: Germ Theory, Gravitation Theory, 3 How to make ATP from NADH Chemiosomotic Theory Proton Motive Force Electron Transport Chain 1 Electrons separated from protons 2 Protons accumulate outside cell An Electron Transport Chain ETC 4 Electron Carriers (exclusive): Iron Sulfur Protein complexes Electron Carriers (again exclusive): Hemes & Cytochromes cytochrome protein heme/porphyrin group Iron molecule 5 Hydrogen Carriers: Flavins Isoalloxazine (oxidized) Isoalloxazine (reduced) Isoalloxazine (oxidized) ribose FMN = Flavin Mononucleotide ribose adenine FAD+ = Flavin Adenine Dinucleotide Hydrogen Carrier: Quinones Oxidized + 2[H] (2e + 2H ) Reduced 6 Hydrogen carriers vs. Electron carriers Quinones are PRIMARILY Hydrogen ion Carriers (sometimes transport electrons) Hemes, FeS centers, and cytochromes (all with metal cofactors) are EXCLUSIVELY electron carriers. H+ Cytochrome Oxidase: End of the line ! Complex (multisubunit) Enzyme Contains heme groups and copper ions O Reduced to H O 2 2 7 The Electron Transport Chain Reduction Potential The ability to receive electrons. The more + the reduction potential, the greater the ability to attract e away from a protein complex or compound with a less + reduction potential. Oxygen has the greatest reduction potential. 8 Making energy with a water gradient How does ATPase Work? Making energy with a proton gradient inside outside g inside inside 9 One Glucose Molecule Yields: Glycolysis Net 2 NADH (Convertible to 3 ATP each) ATP Net 2 ATP (substrate level phosphorylation) Krebs Cycle (x2 for 2 pyruvates) Net 2 ATP (substrate level phosphoylation) Net 8 NADH (Convertible to 3 ATP each) Net 2 FADH (Convertible to 2 ATP each) 2 Total Conversion to ATP 10 What happens next? Glycolysis Krebs Cycle Fermentation ETC NADH ATP Carbon Flow Text References th Pages 120126 (11 Edition) 11 ...
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This homework help was uploaded on 03/21/2008 for the course PY 211 / 212 taught by Professor Chilton during the Spring '08 term at N.C. State.

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