Question

Outline and explain the parts of the chemiosmotic theory

Answer 1

Postulates of Chemiosmotic theory;

1) an electron transport chain, providing the energy for H+ transfer from one side to other side of the membrane

2) ATP synthase, synthesizing/hydrolysing ATP through H+ translocation

3) impermeability of the inner mitochondrial membrane to ionic species thereby including protons.

The basic requirement for the oxidative phosphorylation (OXPHOS) is a coupling between redox processes, proton translocation and ATP synthesis. Such global coupling can arbitrarily be divided into two distinct phases: a coupling between the oxidation-reductive process and the protonic translocation, referred as ‘RedOx coupling’ or ‘first coupling’

And the coupling between protons accumulated on the p-side of the membrane moving to the n-side through the ATP synthase, which determines the synthesis of ATP, here referred as ‘proton coupling’ or ‘second coupling’