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Electron Transport chain Critical elements source of electrons Redox potentials Membrane potentials Proton transport ATP synthesis More Bits Q- Cycle Transport cycles of essential elements Chemiosmotic theory Worth two Chemistry Nobel prizes
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Electron Transport chain • Critical elements • source of electrons • Redox potentials • Membrane potentials • Proton transport • ATP synthesis
More Bits • Q- Cycle • Transport cycles of essential elements • Chemiosmotic theory • Worth two Chemistry Nobel prizes • 1978 Peter Mitchell Nobody believed it for the first 10 years • 1997 to Paul D. Boyer and John E. Walker. Elucidation of FoF1 ATPase mechnism • Amazingly efficient ≈70% DG captured under physiological conditions (cars are < 30%)
Figure 22-10 Pge 804
Nerst equation • E’=Eo’– (2.3RT/nF)Log [Red]/[Oxi] • E’=Eo’– (0.059V/n)Log [Red]/[Oxi] • E’=Eo’- (RT/nF)ln [Red]/[Oxi] • Conversion of DE to DG • DG= -nFDE’
Figure 22-2b Page 799
NADH in Calcium Balance| Pi in ADP in ATP out Acetyl-S-CoA out Malate aspatate shuttle/glycerolphosphate shuttle Na/Ca exchange outTran/sys in Phosphate carrier /DH+ Adenine Nucleotide Translocase Citrate/pyruvate transport Transport
Figure 22-5 The two mitochondrial Ca2+ transport systems. Page 800
Glycyrol 3 phosphate shuttle DHAP Glycerol 3 phosphate Glycerol 3 phosphate DHAP FADH FAD Membrane bound Complex II Nad NadH Co Enzyme Q
Figure 22-1 Page 798
Figure 22-13 Determination of the stoichiometry of coupled oxidation and phosphorylation (the P/O ratio) with different electron donors. Page 807
Electron Transport Chain • 4 complexes • Complex 1 • entry point of NADH • pumps 2-4 protons • inhibited by rotenone of amatal • Complex 2 • Succinate Dehydrogenase • Entry point of FADH2 • reduces CoQ/Ubiquinone
Electron Transport Chain • 4 complexes • Complex 3 • bc1 complex • Pumps 2-4 protons • Involved in Q Cycle Passes electrons to Cyt • Inhibited by Antimycin A • Complex 4 Oxygen reduction complex Cytochrome a a1 Copper containing proteins Inhibited By Cyanide
Electron transport chain • NAD+ + H+ + 2e- <---> NADH [-0.32 V] • FAD + 2H+ + 2e- <---> FADH2 [-0.22 V] • FMN + 2H+ + 2e- <---> FMNH2 [-0.12 V] • CoQ + 2H+ + 2e- <---> CoQH2 [+0.10 V] • Cyt c (Fe3+) + e- <---> Cyt c (Fe2+) [+0.22 V] • Cyt a (Fe3+) + e- <---> Cyt a (Fe2+) [+0.29 V] • O2 + 2H+ + 2e- <---> H2O [+0.82 V]
Figure 22-14 The mitochondrial electron-transport chain. Page 808
Figure 22-9 Page 803