Question

Which of the following statements is true?

A) The NADH dehydrogenase complex can pump more protons than can the cytochrome b-e1, complex.
B) The pH in the mitochondrial matrix is higher than the pH in the intermembrane space.
C) The proton concentration gradient and the membrane potential across the inner mitochondrial membrane tend to work against each other in driving protons from the intermembrane space into the matrix.
D) The difference in proton concentration across the inner mitochondrial membrane has a much larger effect than the membrane potential on the total proton-motive force.

Answer 1

B) The pH in the mitochondrial matrix is higher than the pH in the intermembrane space. Hence, B) is correct.

Step-by-step explanation:

The correct statement is B) The pH in the mitochondrial matrix is higher than the pH in the intermembrane space.

The chemiosmotic theory explains that during electron transport in mitochondria, protons are pumped from the matrix to the intermembrane space, creating an electrochemical gradient.

This gradient causes the protons to flow back into the matrix through the ATP synthase complex, which leads to the synthesis of ATP. This flow of protons through ATP synthase is called chemiosmosis, and it only occurs because the pH in the intermembrane space is lower than the pH in the mitochondrial matrix.