Oxidative Phosphorylation 0.0 / 5 ? BiologyCellular processesA2/A-levelOCR Created by: BethCreated on: 08-02-14 17:44 Oxidative Phosphorylation (def) The formation of ATP by adding a phosphate group to ADP, in the presence of oxygen, which is the final electron acceptor 1 of 18 What happens when reduced NAD and reduced FAD are reoxidised? They donate hydrogen atoms (2H) which are spilt into protons(2H+) and electrons (2e-) 2 of 18 First Electron Acceptor NADH dehydrogenase (accepts electrons from reduced NAD) 3 of 18 Protons Go into solution in the matrix (mitochondria) 4 of 18 Electron Transport Chain The electrons are passed along a chain of electron carriers and then donated to molecular oxygen, the final electron acceptor 5 of 18 Chemiosmosis (1) Energy released in the electron transport chain is used by coenzymes to pump protons across the inter membrane space 6 of 18 Chemiosmosis (2) This builds a pH/electrochemical gradient (Proton Gradient) 7 of 18 Chemiosmosis (3) Hydrogen ions can only diffuse through ion channels, which are associated with enyzme ATP synthase 8 of 18 Chemiosmosis (def) The flow of hydrogen ions through a partially permeable membrane (down the diffusion gradient) 9 of 18 Oxidative Phosphorylation (1) As protons flow through an ATP synthase enzyme, they drive the rotation of part of the enzyme and join ADP and inorganic phosphate to form ATP 10 of 18 Oxidative Phosphorylation (2) The electrons are passed from the last electron carrier in the chain to molecular oxygen, which is the final electron acceptor 11 of 18 Oxidative Phosphorylation (3) Hydrogen ions also join so that oxygen is reduced to water... 4H+ + 4e- + O2 = 2H2O 12 of 18 How much ATP is made before Oxidative Phosphorylation? 2 gained = Glycolysis (substrate level phosphorylation), 2 made = Krebs cycle (substrate level phosphorylation) 13 of 18 How many ATP molecules can be produced per molecule of reduced NAD? 2.6 14 of 18 What is the total yield of ATP, when combined with the ATP from glycolysis and the Krebs cycle? 30 15 of 18 Why is the theoretical yield of ATP rarely achieved? (1) Some protons leak across the mitochondrial membrane, reducing the number of protons to generate the proton motive force 16 of 18 Why is the theoretical yield of ATP rarely achieved? (2) Some ATP is used to actively transport pyruvate into the mitochondria 17 of 18 Why is the theoretical yield of ATP rarely achieved? (3) Some ATP is used for the shuttle to bring hydrogen from reduced NAD made during glycolysis, in the cytoplasm, into the mitochondria 18 of 18
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