Question

Mitochondria isolated and placed in a buffered solution with a low pH begin to manufacture ATP. Which of the following is the best explanation for the effect of low external pH?

• A. It increases the concentration of $O{H}^{–}$ causing the mitochondria to pump $H^{+}$
• B. It increases the $O{H}^{–}$ concentration in the mitochondria matrix
• C. It increases the acid concentration in the mitochondria matrix
• D. It increases diffusion of $H^{+}$ from the intermembrane space to the matrix

Answer 1

The correct option is D It increases diffusion of $H^{+}$ from the intermembrane space to the matrix

If mitochondria is placed in a buffered solution with low pH, it increases the concentration of $H^{+}$ and causes diffusion of $H^{+}$ ions from the intermembrane space to matrix. It generates a pH gradient across the inner mitochondrial membrane. The diffusion of $H^{+}$ ions lead to ATP production.