Calculate the number of usable ATP molecules produced per pair of electrons transferred from NADH to oxygen if

(i) Five protons are pumped across the inner mitochondrial membrane for each electron passed though the three respiratory enzyme complexes.

(ii) Three protons must pass through the ATP synthase for each ATP molecule that it produces from ADP and inorganic phosphate inside the mitochondrion.

(iii) One proton is used to produce the voltage gradient needed to transport each ATP molecule out of the mitochondrion to the cytosol where it is used.