Oxidative Phosphorylation
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OXIDATIVE PHOSPHORYLATION
Electron transport chain
- Series of controlled redox reactions; pumps H+ into inter-membrane space
Chemiosmosis
- Couples e- transport w/ ATP synthesis
Complex I: NADH dehydrogenase
- aka NADH-CoQ reductase
- NADH delivers 2 electrons to the complex I and is oxidized to NAD+
CoQ (aka Q10 and ubiquinone)
- Lipid-soluble
- Mobile carrier
- NOT a protein
Complex II: succinate dehydrogenase
- aka Succinate-CoQ reductase
- Also part of citric acid cycle
- FADH2 delivers two electrons to complex II
Complex III: Cytochrome bc1 complex
- aka CoQ-cytochrome c reductase
Cytochrome C
- Water-soluble
- Mobile carrier
Complex IV: cytochrome c oxidase
- Produces one H2O from 2 H+ plus ½ O2 + 2e-
- Complexes I, III & IV pump H+ from matrix to inter-membrane space
Complex V: ATP synthase
- Inner mitochondrial membrane IMPERMEABLE to most small molecules
- H+ that is pumped across membrane cannot diffuse back through the bilayer
- H+ diffuses down gradient through ATP synthase into the matrix
- Produces 30-34 ATP per glucose molecule (NADH = 3 ATP, FADH2 = 2 ATP