Electron Transport and Oxidative Phosphorylation

Objectives: I. Describe the structure of the Mitochondrion. A. Compare the structure of the outer membrane to the structure of the inner membrane. B. What metabolic pathways are localized to the mitochondrion? 1. Where in the mitochondrion are they located? II. What is(are) the overall chemical reaction(s) of electron transport and oxidative phosphorylation? III. Describe the overall makeup of the Electron Transport / Oxidative Phosphorylation pathway. A. Number of complexes present in the system. 1. Which complexes carry electrons? B. Describe the electron carriers present in each of the complexes. C. Describe the electron carriers that are part of the pathway but are not part of the complexes. D. Describe the “flow” of electrons “down” the Electron Transport Chain. E. Describe the use of Respiratory Inhibitors in elucidating the sequence of electron transport. IV. Describe how the energy released by the Electron Transport Chain is used. A. How does the nature of the complexes facilitate establishment of the proton gradient? B. How does the nature of the inner mitochondrial membrane function to maintain the proton gradient? V. Describe ATP synthesis during Electron Transport / Oxidative Phosphorylation pathway. A. Complex involved. B. How is the proton gradient utilized to synthesize ATP? 1. Describe the use of Uncouplers in elucidating the mechanism of ATP synthesis. C. Describe the mechanism of ATP synthesis. D. Distinguish substrate level phosphorylation from oxidative phosphorylation. VI. ATP Yield A. Yield of ATP (moles) per mole of NADH/H+ oxidized by the electron transport chain. 1. Theoretical versus Actual B. Yield of ATP (moles) per mole of FADH2 oxidized by the electron transport chain. 1. Theoretical versus Actual C. What other process utilizes the proton gradient? 1. How? VII. Calculate the overall yield of ATP from glucose metabolized under aerobic conditions. A. Compare and contrast the shuttles that move NADH from the cytoplasm into the mitochondrion. 1. Discuss why the shuttles result in different ATP yields per NADH transported from the cytoplasm. VIII.Ask yourself “What If Questions”; e.g., What happens if complex III is inhibited?