When mitochondria are carrying out aerobic respiration...pH of the matrix,intermembrane space.

Question

When mitochondria are actively carrying out aerobic respiration:

a) the pH of the matrix is greater than the pH of the intermembrane space.

b) the pH of the matrix is less than the pH of the intermembrane space.

c) the pH of the matrix is about the same as the pH of the

intermembrane space.

d) the pH of the matrix versus the intermembrane space has nothing to do with whether not aerobic respiration is occurring.

Answer 1

In the presence of oxygen

Answer 2

The answer is a), although there is a less than 0.5 pH difference between the two compartments.  When electrons are pumped through the electron transport chain, hydrogen ions are concomitantly pumped from the matrix to the intermembrane space,making the intermembrane space slightly more acidic than the matrix.  A more acidic environment means a lower pH.