Which of the following complexes does not directly contribute to the production of ATP by pumping protons?
A) Complex I.
B) Complex II.
C) Complex III.
D) Complex IV.
E) All four complexes pump protons.

Question

Quizplus · Accepted Answer

Complex II does not pump protons across the mitochondrial membrane. It participates in the electron transport chain by transferring electrons from succinate to coenzyme Q (ubiquinone), but it does not contribute to the proton gradient used for ATP synthesis by oxidative phosphorylation.

Which of the Following Complexes Does Not Directly Contribute to the Production