Question

When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the
A) formation of ATP.
B) reduction of NAD⁺.
C) restoration of the Na⁺/K⁺ balance across the membrane.
D) creation of a proton-motive force.
E) lowering of pH in the mitochondrial matrix.

Answer 1

Answer:

D) creation of a proton-motive force.

Explanation:

• When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the creation of a proton-motive force.
• The proton gradient generated by proton pumping during the electron transport chain is a stored form of energy.
• When protons flow back down their concentration gradient (from the intermembrane space to the matrix), their only route is through ATP synthase, an enzyme embedded in the inner mitochondrial membrane.