L15_2009 Bioenergetics II Oxidative phosphorylation - fermentation

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Unformatted text preview: ists said wouldn’t work.” Peter Mitchell 1920-1992 Nobel Prize 1978 Peter Mitchell (1961). "Coupl i ng of phosphoryl ati on to electron and hydrogen transfer by a chemi-osmotic type of mechanism". Nature 191: 144–148 Chemiosmosis Ef Racker Efraim Racker (1913-1991), a biochemist at Cornell University was the first to purify the F1 particle (ATP synthase catalytic knobs) from the mitochondrial membrane. Along with Cornell’s Andre Jagendorf, and Peter Hinkle, he studied its function in an artificial membrane fragment system. Electron transport chain chemiosmosis CHEMIOSMOSIS Support for Chemiosmosis Hypothesis ATP SYNTHASE 1. pH in intermembrane space of the mitochondrion is lower than outside. (A proton-powered motor for generating ATP) 2. A proton gradient is all that is necessary for ATP synthesis. Electron transport is not required. Reconstitution experiment: artificial ATP synthesis Racker & Stoeckenius: ATP synthesis in artificial system with three components (1) artificial membrane vesicles (2) isolated mitochondrial particles from beef heart (3) bacteriorhodopsin (H+ pump activated by light). How ATP Synthase works Summary of electron transport and chemiosmosis Nobel Prize 1997 i ntermembrane space matrix Paul Boyer John W alker intermembrane space F0 matrix F1 Yield from aerobic catalysis of glucose What if there is no oxygen ? Fermentation reactions allow ATP to be generated in the absence of oxygen Fermentation reactions allow ATP to be generated in the absence of oxygen Yeast _ Clicker question Since Bacteria and Archaea lack organelles, do they perform oxidative phosphorylation ? A. No, they typically live in anaerobic environments B. Yes, with their mitochondria like protists do C. No, they only perform glycolysis D. Yes, with electron transport proteins on the inner surface of their plasma membrane E. No, but many perform fermentation Other compounds can be substrates for cellular respiration = OH S-CoA oxidation of fatty acids 2 carbons at a time in the mitochondrial matrix 2 Next up - Photosynthesis...
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This note was uploaded on 12/21/2012 for the course BIOMG 1101 taught by Professor Colegilbert during the Fall '09 term at Cornell University (Engineering School).

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