Question

The chemiosmotic hypothesis invovles all of the following, except

• A. Only proton transport is strictly regulated, other positively charged ions can diffuse freely across the mitochondrial membrane.
• B. A membrane impermeable to photons.
• C. Electron transport by the respiratory chain pumps proton out of the mitochondria.
• D. ATPase activity is reversible.

Answer 1

The correct option is A Only proton transport is strictly regulated, other positively charged ions can diffuse freely across the mitochondrial membrane.

The Chemiosmostic hypothesis suggests that the action of ATP synthase is coupled to the movement of protons across a semipermeable membrane, down the proton gradient.
Therefore, although the proton transport is strictly regulated, this is true for all ions. Any ion that needs to translocate across a membrane, does so via a protein channel.