Oxidative Phosphorylation Quiz

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@AdulatoryChalcedony8800

Study Notes

Oxidative phosphorylation, also known as the electron transport chain, is a series of proteins and organic molecules in the inner mitochondrial membrane
Electrons are passed from one member of the transport chain to another in redox reactions
The electron transport chain regenerates electron carriers and makes a proton gradient.

Describe the movement of electrons through the electron transport chain
State the products of oxidative phosphorylation
Outline the role of NADH and FADH2 and electron carriers in the electron transport chain
Describe the chemiosmotic theory of ATP production

Complex I (NADH Dehydrogenase): NADH binds to complex I, donating electrons to flavin mononucleotide (FMN). The electrons are transferred through iron-sulfur clusters, and four protons are pumped from the matrix into the intermembrane space
Complex II (Succinate Dehydrogenase): The only enzyme part of both the citric acid cycle and the electron transport chain. It oxidizes succinate to fumarate, reducing ubiquinone (Q). This reaction releases less energy than NADH oxidation, so no protons are pumped across the membrane.
Complex III (Cytochrome c Reductase): Oxidizes ubiquinol (QH2) and reduces cytochrome c. One proton is transferred per cytochrome c reduced.
Complex IV (Cytochrome c Oxidase): The final protein complex in the electron transport chain. This enzyme transfers electrons to oxygen, reducing it to water (H₂O). Protons are pumped across the membrane.
ATP Synthase (Complex V): Uses the energy stored in the proton gradient across the membrane to produce ATP from ADP and phosphate (Pi).

Chemiosmosis is when H+ ions move across a semipermeable membrane (from a higher to lower concentration). The flow is down the H+ gradient created by the electron transport chain.

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