Question

Which of the following statements is true?

a)The NADH dehydrogenase complex can pump more protons than can the cytochrome b-c1 complex
b) the pH in the mit. matrix is higher than the pH in the intermembrane space
c)the proton concentration gradient and the membrane potential across the inner mit. 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

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.

Step-by-step explanation:

The correct statement among the given options is c) the proton concentration gradient and the membrane potential across the inner mit. membrane tend to work against each other in driving protons from the intermembrane space into the matrix.

In the electron transport chain of cellular respiration, protons are pumped from the matrix to the intermembrane space, creating a proton concentration gradient. Additionally, electrons passing through the electron transport chain create a membrane potential across the inner mitochondrial membrane. These two forces, the proton concentration gradient and the membrane potential, tend to work against each other in driving protons from the intermembrane space into the matrix.

However, it is important to note that both the proton concentration gradient and the membrane potential contribute to the total proton-motive force, which drives ATP synthesis through the chemiosmotic mechanism.