What would happen if mitochondria were treated with a proton gradient uncoupler,such as 2,4-dinitrophenol?
A) Electron transfer would stop.
B) Complex I would become reduced, and complexes III and IV would become oxidized.
C) Protons would be pumped by the mitochondrial electron transport chain, although no ATP would be synthesized.
D) Reducing equivalents, in the form of NADH, would no longer be consumed.

Question

Quizplus · Accepted Answer

Proton gradient uncouplers such as 2,4-dinitrophenol disrupt the coupling between electron transport and ATP synthesis by allowing protons to leak back into the mitochondrial matrix, thereby preventing ATP synthesis. However, the electron transport chain would still function, pumping protons across the inner mitochondrial membrane. This would result in a high concentration of protons in the intermembrane space and a lower concentration in the mitochondrial matrix. This proton gradient drives ATP synthesis in normal conditions, but in the presence of a proton gradient uncoupler, the gradient would still be established but no ATP would be synthesized.

What Would Happen If Mitochondria Were Treated with a Proton