Question

A proton gradient across the mitochondrial inner membrane is a requisite for the synthesis of ATP. What contributes to the creation of this proton gradient?

A.
more protons in the mitochondrial matrix than in the inter membrane space of the mitochondria
B.
more protons in the intermembrane space of the mitochondria than in the mitochondrial matrix
C.
equal number of protons in the mitochondrial matrix and the intermembrane space of the mitochondria

Answer 1

So the question is regarding ATP production in oxidative phosphorylation. First, the electron transport chain takes the NADH and FADH from the previous steps of cellular respiration and conducts a redox reaction to remove the H+ ions. These ions are sent to the inner mitochondrial membrane from the matrix.

NOW, the H+ ions will form a proton gradient and conduct chemiosmosis. This sends H+ ions from the inner mitochondrial matrix through ATP synthase to make ATP from ADP and Inorganic phosphate (back in the matrix). Hence, to conduct chemiosmosis, there should be more protons in the intermembrane space than in the matrix.