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Oxidative Phosphorylation Part 1 of Three Chapter 19
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Oxidative Phosphorylation Part 1 –Electron-transport chain in mitochondria –Redox calculations –E-transport inhibitors –Building up the proton-motive force Key topics: To Know EOC Problem 1 is all about recognizing electron donors and acceptors…a quick review to make the rest of the chapter easy.
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Mitochondria Review Chapters: 16,17,18 Chapter 19
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SEM of Mitochondia
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Mitochondia in Heart and Liver Attempts to show more inner membrane structure in heart mitochondria compared to liver mitochondria.
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Dehydrogenases in Cytoplasm and Mitochondria
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Quinones – 1 and 2 electron carriers EOC Problem 2 looks at the ubiquinone parts and their functions. Note the isoprene length.
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Cytochromes One Electron Carrier
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Cytochromes Easily Measured by Spectrophotometry
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Difference Spectrum Vibrio harveyi. Taken from: Guerrero and Makemson 1989 Current Microbiology 18:67-73 Difference Spectrum (Reduced – Oxidized)
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Iron Sulfur Protein Models
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Electron Transport Carriers Redox Tower
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Electron Carrier Sequence Determined from Inhibitors
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Electron Transport Inhibitors
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Isolation of Complexes from Mitochondria
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Electron Carriers Arranged in Modules (Complexes)
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Entry Points to Electron Transport EOC Problem 3: why is it that Succinate has to use FAD rather than NAD + ?
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Complex I
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Complex I Structure is Solved Efremov, RG et al., May, 2010 Nature 465:441-445 in cytoplasmic membrane Cytoplasm Periplasm Is this from mitochondria or bacteria?
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Complex I Working H+H+ H+H+ H+H+ H+H+
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Complex II
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Entry Points to Electron Transport
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Complex III
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Complex IV
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Complex IV : Proton Pumping/Oxygen Reduction
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Yeast Complex III and IV Respirasome TEM (whole, Uranyl Acetate) Superimpose Xray Structures Composite of 100’s of Images Complex IV Complex III greenred
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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 !
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Summary of Electron Transport Complex I Complex IV 1NADH + 11H + (N) + ½O 2 ——> NAD + + 10H + (P) + H 2 O Complex II Complex IV FADH 2 + 6H + (N) + ½O 2 ——> FAD + 6H + (P) + H 2 O Difference in number of protons transported reflects differences in ATP synthesized.
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Complex 1,3,4 or 2,3,4
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Calculations Differences between half cells…Example of electron transfer from NADH to ubiquinone (going from NADH through Complex I to ubiquinone): NADH E o ’ = -.32 v Ubiquinone E o ’ = 0.045 v ΔE o ’ = E o ’oxidized – E o ’ reduced = 0.045v – (-0.32v) ΔE o ’ = 0.365 v
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ΔG’ o Calculation What is the ΔG’ o for oxidation of NADH by ubiquinone ΔG’ o = - nƑΔE o ’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?
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Things to Know and Do Before Class 1.Where the DH’s are. 2.The electron transport players: flavin, Fe-S centers, cytochromes (and their properties), quinones, Cu ++. 3.Is it the ABCs of electron transport or the BCAs? 4.Effects of electron transport inhibitors. 5.Entry points and what each complex does. 6.How to calculate ΔG o ’ from ΔE o ’. 7.EOC Problems: 1-5.
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