What is complex IV in the ETS of mitochondria?

The electron transport system (ETS):

1. The electron transport system is present in the inner membrane of mitochondria.
2. This system is focused on n the generation of ATP and is the third step in the cellular respiration process.
3. It consists of nine electron carriers that are grouped into four multiprotein complexes,i.e. Complex- I, complex II, complex III, complex IV, and complex V.
4. Out of nine electron carriers, co-enzyme-Q and cytochrome C are considered mobile electron carriers.

Complex-IV of ETS:

1. Complex-IV is a cytochrome c oxidase enzyme.
2. It consists of cytochrome-a, cytochrome-a₃, haem, and copper ions as prosthetic groups.
3. Complex IV, also known as cytochrome c oxidase, catalyzes the final step in the mitochondrial electron transport chain and is one of the key regulators of oxidative phosphorylation.
4. The name cytochrome c oxidase comes from the fact that Complex IV absorbs electrons from cytochrome c.
5. Complex IV is also responsible for transferring electrons to oxygen (O₂).
6. By taking two hydrogen ions, oxygen functions as a final electron acceptor and converts to water.