Question

Cytochrome c oxidase is an enzyme complex that uses metal ions to help coordinate the

transfer of four electrons to O2. Which metal atoms are found in the active site of this
complex?
(a) two iron atoms
(b) one iron atom and one copper atom
(c) one iron atom and one zinc atom
(d) one zinc atom and one copper atom

Answer 1

Cytochrome c oxidase contains one iron atom and one copper atom in its active site, crucial for reducing oxygen to water and assisting in chemiosmosis.

Step-by-step explanation:

The metal atoms found in the active site of cytochrome c oxidase, which is Complex IV in the electron transport chain, are one iron atom and one copper atom. This enzymatic complex plays a crucial role in cellular respiration by reducing oxygen into water.

The cytochromes hold the oxygen molecule tightly between the two metal ions until the oxygen is completely reduced, which then picks up two hydrogen ions to form water (H₂O).