Electron Transport chain

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Electron Transport chain

• Critical elements
• source of electrons
• Redox potentials
• Membrane potentials
• Proton transport
• ATP synthesis

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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 lt 30)

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Figure 22-10
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• Nerst equation
• EEo (2.3RT/nF)Log Red/Oxi
• EEo (0.059V/n)Log Red/Oxi
• EEo- (RT/nF)ln Red/Oxi
• Conversion of DE to DG
• DG -nFDE

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Figure 22-2b
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Transport

• 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

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Figure 22-5 The two mitochondrial Ca2 transport
systems.
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Figure 22-6 The regulation of cytosolic Ca2.
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Figure 22-7
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Glycyrol 3 phosphate shuttle

• Nad? NadH

DHAP ? Glycerol 3 phosphate
Glycerol 3 phosphate ? DHAP
FADH ? FAD
Membrane bound Complex II
Co Enzyme Q
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Figure 22-1
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Figure 22-13 Determination of the stoichiometry
of coupled oxidation and phosphorylation (the P/O
ratio) with different electron donors.
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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

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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

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Electron transport chain

• NAD H 2e- lt---gt NADH -0.32 V
• FAD 2H 2e- lt---gt FADH2 -0.22 V
• FMN 2H 2e- lt---gt FMNH2 -0.12 V
• CoQ 2H 2e- lt---gt CoQH2 0.10 V
• Cyt c (Fe3) e- lt---gt Cyt c (Fe2) 0.22 V
• Cyt a (Fe3) e- lt---gt Cyt a (Fe2) 0.29 V
• O2 2H 2e- lt---gt H2O 0.82 V

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Figure 22-14 The mitochondrial electron-transport
chain.
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Figure 22-9
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