The rate of oxidative phosphorylation
I.is regulated by the availability of ADP and P_i.
II.is reduced when the ratio of [NADH]/[NAD⁺] is high.
III.increases with a higher concentration of reduced cytochrome c
IV.is regulated by activity of the ADP-ATP translocator.

Question

Quizplus · Accepted Answer

The rate of oxidative phosphorylation is regulated by the availability of ADP (to phosphorylate) and oxygen (to accept electrons) (I) and the activity of the ADP-ATP translocator which regulates the movement of ADP and ATP across the inner mitochondrial membrane (IV). The rate of oxidative phosphorylation decreases when the ratio of [NADH]/[NAD+]*[Pi] (where [Pi] represents concentration of inorganic phosphate, HPO42-) is high (II), indicating that there is enough electron donor and low amounts of substrate for ATP synthesis. The concentration of reduced cytochrome c is an indicator of electron transfer activity and does not directly regulate the rate of oxidative phosphorylation, hence it is not a correct choice (III).

The Rate of Oxidative Phosphorylation