Which Complex in the Electron-Transport Chain Contains Copper Ions

Question

Which complex in the electron-transport chain contains copper ions?
A) Complex I
B) Complex II
C) Complex III
D) Complex IV
E) None of these complexes contains copper ions.

Accepted Answer

Complex IV, also known as cytochrome c oxidase, contains copper ions. Specifically, there are two copper ions, labeled CuA and CuB, which are involved in transferring electrons and ultimately reducing oxygen to form water.