Question

The chemiosmotic coupling hypothesis of oxidative phosphorylation proposes that adenosine triphosphate (ATP) is formed because:

• A. A proton gradient forms across the inner membrane
• B. There is a change in the permeability of the inner mitochondrial membrane toward adenosine diphosphate (ADP)
• C. High energy bonds are formed in mitochondrial proteins
• D. ADP is pumped out of the matrix into the intermembrane space

Answer 1

The correct option is A A proton gradient forms across the inner membrane

Chemiosmotic theory was postulated by the British biochemical Peter Mitchell (1920-1922) to explain the formation of ATP in the mitochondrial electron transport chain.
As electrons are transferred along the electron carrier system in the inner mitochondrial membrane, hydrogen ions (protons) are actively transported into the space between the inner and outer mitochondrial membranes.
Thus an electrochemical gradient is created across the inner membrane, which is utilised by the enzyme ATP synthase to generate ATP.