Question

What role does cytochrome C oxidase play in aerobic respiration?

Answer 1

Cytochrome c oxidase:

1. Cytochrome c oxidase is also known as complex IV is one of the enzyme complexes of the electron transport system.

Role of cytochrome c oxidase:

1. It catalyses the last step of ETS. It contains cytochromes a and a3, and two copper centres.
2. It transfers electrons from cytochrome c to O₂ the final electron acceptor in aerobic respiration and forming H₂O.
3. Electron transfer in ETS is coupled with ATP synthesis by ATP synthase, the free energy from the electron transfer causes 4 protons to move into the intermembrane space contributing to the proton gradient.
4. Oxygen reduces via the following reaction:
   2 cytochrome c (red) + ½O₂ + 4 H+(matrix) -> 2 cytochrome c (ox) + 1 H₂O + 2 H+ (intermembrane)