Ques. 1AIPMT 2008
The chemiosmotic coupling hypothesis of oxidative phosphorylation proposes that adenosine triphosphate (ATP) is formed because
- a proton gradient forms across the inner membrane
- there is a change in the permeability of the inner mitochondrial membrane toward adenosine diphosphate (ADP)
- high energy bonds are formed in mitochondrial proteins
- ADP is pumped out of the matrix into the intermembrane space
Answer
(1) a proton gradient forms across the inner membrane
Solution
As per NCERT, the energy released during the electron transport system is used to pump protons from the matrix to the intermembrane space, creating a proton gradient across the inner mitochondrial membrane.
The protons then flow back to the matrix through the F0 channel of ATP synthase (F0 – F1 complex), and the energy of this proton flow is used by F1 to synthesise ATP from ADP and inorganic phosphate.
Answer: (1)