MUSCLE PHYSIOLOGY

Detailed explanation-1: -This process is referred to as chemiosmosis because of the difference in H+ ion concentration between the intermembrane space and the mitochondrial matrix. The electrochemical gradient generated by H+ ions pumped into the intermembrane space is termed the ‘proton motive’ force.

Detailed explanation-2: -During electron transport, energy is used to pump hydrogen ions across the mitochondrial inner membrane, from the matrix into the intermembrane space. A chemiosmotic gradient causes hydrogen ions to flow back across the mitochondrial membrane into the matrix, through ATP synthase, producing ATP.

Detailed explanation-3: -The electrons flow through the electron transport chain, causing protons to be pumped from the matrix to the intermembrane space.

Detailed explanation-4: -This transfer of protons from the matrix to the intermembrane space plays the critical role of converting the energy derived from the oxidation/reduction reactions of electron transport to the potential energy stored in a proton gradient.

Detailed explanation-5: -Complex I can pump four hydrogen ions across the membrane from the matrix into the intermembrane space, and it is in this way that the hydrogen ion gradient is established and maintained between the two compartments separated by the inner mitochondrial membrane.