Bio 201 1st Edition Lecture 22 Outline of Last Lecture I. FermentationA. AlcoholicB. Lactic AcidC. Anaerobic Metabolism SummaryII. Aerobic MetabolismA. The 4 PathwaysOutline of Current LectureI. Pathways of Aerobic MetabolismA. Electron Transport SystemB. ATP SynthaseCurrent LectureI. Pathways of Aerobic Metabolism- There are 4 all together. A. Electron Transport System- This is the third pathway. The third purpose is to capture energy from oxidation of NADH and FADH2 to form a proton (H+) gradient across inner mitochondrial membrane, designed for efficiency. O2 is the recipient of electrons. -Energetics of electron transport: Reduction potential- The tendency to accept electrons, measured in volts. (whoever wants the electron more has a higher reductionpotential) The forward reaction, transfer of electrons from A B is favorable, only if the reduction potential of B is greater than that of A. For all favorable reactants the change in G (free energy) is < 0. The free energy of oxidation of A is higher than that of B. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-Electrons from NADH and FADH2 are transferred step-wise to substances with ever increasing reduction potentials. O2 is the final electron acceptor, FADH2 has a higher reduction potential that complex I, so it transfers electrons to Complex II, which has a higher reduction potential. Electron transfer is coupled to H+ transport across the inner mitochondrial membrane. -Proton pumping is major for development of proton gradient. Reduction of water happens in matrix, consume protons. Using proton gradient: chemiosmotic coupling. In mitochondria: diffusion of protons across inner mitochondrial membrane. In chloroplasts: diffusion of H+ gradient across thylakoid membranes. Discovery? 1. Isolate thylakoid membranes 2. Create an artificial H+ gradient 3. Add ADP and P1. ATP. ATP SYNTHASE= Oxidative phosphorylation. B. ATP Synthase- Chemiosmotic coupling requires proton complexes Fo and F1 to worktogether. Fo is anchored in membrane making a proton gradient channel. F1 dissociated form membrane in weak detergent causing ATP synthase. Diffusion of proton down gradient thru Fo rotation of F1 ATP phosphorylation. Rotation is reversible, H+ going into cytoplasm from periplasmic space is counterclockwise, opposite is clockwise. -When you uncouple H+ from ATP synthase you can die!!!!! It causes your body to cook, for example, the DNP diet
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