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Chapter 19

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Chapter 19

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  1. Chapter 19 Oxidative Phosphorylation Part 1 of Three

  2. Oxidative Phosphorylation Part 1 Key topics: To Know • Electron-transport chain in mitochondria • Redox calculations • E-transport inhibitors • Building up the proton-motive force EOC Problem 1 is all about recognizing electron donors and acceptors…a quick review to make the rest of the chapter easy.

  3. Mitochondria Review Chapter 19 Chapters: 16,17,18

  4. SEM of Mitochondia

  5. Mitochondia in Heart and Liver Attempts to show more inner membrane structure in heart mitochondria compared to liver mitochondria.

  6. Dehydrogenases in Cytoplasm and Mitochondria

  7. Quinones – 1 and 2 electron carriers EOC Problem 2 looks at the ubiquinone parts and their functions. Note the isoprene length.

  8. Cytochromes One Electron Carrier

  9. Cytochromes Easily Measured by Spectrophotometry

  10. Difference Spectrum (Reduced – Oxidized) Difference Spectrum Vibrio harveyi. Taken from: Guerrero and Makemson 1989 Current Microbiology 18:67-73

  11. Iron Sulfur Protein Models

  12. Electron Transport Carriers Redox Tower

  13. Electron Carrier Sequence Determined from Inhibitors

  14. Electron Transport Inhibitors

  15. Isolation of Complexes from Mitochondria

  16. Electron Carriers Arranged in Modules (Complexes)

  17. Entry Points to Electron Transport EOC Problem 3: why is it that Succinate has to use FAD rather than NAD+?

  18. Complex I

  19. Complex I Structure is Solved Periplasm in cytoplasmic membrane Cytoplasm Is this from mitochondria or bacteria? Efremov, RG et al., May, 2010 Nature 465:441-445

  20. Complex I Working H+ H+ H+ H+

  21. Complex II

  22. Entry Points to Electron Transport

  23. Complex III

  24. Complex IV

  25. Complex IV : Proton Pumping/Oxygen Reduction

  26. Yeast Complex III and IV Respirasome Complex IV Complex III green red TEM (whole, Uranyl Acetate) Superimpose Xray Structures Composite of 100’s of Images

  27. Electron Transport Summary EOC Problems 4 and 5 examine aspects of electron transfer and amounts of oxygen, NAD+, and other things such as inhibitors…great problems !

  28. Summary of Electron Transport Complex I  Complex IV 1NADH + 11H+(N) + ½O2 ——> NAD+ + 10H+(P)+ H2O Complex II  Complex IV FADH2+ 6H+(N) + ½O2 ——> FAD + 6H+(P) + H2O Difference in number of protons transported reflects differences in ATP synthesized.

  29. Complex 1,3,4 or 2,3,4

  30. Calculations Differences between half cells…Example of electron transfer from NADH to ubiquinone (going from NADH through Complex I to ubiquinone): NADH Eo’ = -.32 v Ubiquinone Eo’ = 0.045 v ΔEo’ =Eo’oxidized – Eo’ reduced = 0.045v – (-0.32v) ΔEo’ = 0.365 v

  31. ΔG’o Calculation What is the ΔG’o for oxidation of NADH by ubiquinone ΔG’o = - nƑΔEo’ Faraday Constant = 96,480 J/v.mole = 96.5 kJ/v.mole ΔG’o = - (2) 96.5 kJ/v.mole (0.365v) = - 70.4 kJ/mole How Many “ATPs” is this worth?

  32. Things to Know and Do Before Class • Where the DH’s are. • The electron transport players: flavin, Fe-S centers, cytochromes (and their properties), quinones, Cu++. • Is it the ABCs of electron transport or the BCAs? • Effects of electron transport inhibitors. • Entry points and what each complex does. • How to calculate ΔGo’ from ΔEo’. • EOC Problems: 1-5.