Question

Part A: How acidic would the external pH need to become in order to make it possible to synthesize one ATP molecule from the energy delivered when one proton enters the mitochondrial matrix? (Assume ATP formation requires 52.0 kJ/mol, 37 degrees celsius, membrane potential -0.12V, and matrix pH 7.2)

Part B: Comment on whether this pH is feasible, BE SPECIFIC!

Answer 1

The pumping to H+ across the membrane from the matrix to the intermembrane space generates a a pH gradient across the inner mitochondrial membrane. The matrix will have pH higher than the cytosol which has pH close to 7. This generates membrane potential across the inner mitochondrial membran with a negative inside and the positive outside. The electrochemical proton gradient existing across the inner mitochondrial membrane drives ATP synthesis by oxidative phosphorylation by the membrane-bound enzymeATP synthase. This enzyme allows protons to flow down their electrochemical gradient accross the mitochondrail membrane. This ions drive the ATP formation from ADP and Pi.

This pH difference is necessary for energy production.