What is the link between electron transport and ATP synthesis?

What is the link between electron transport and ATP synthesis?

• A. The direct transfer of electrons to ADP forms ATP.
• B. Wireless energy is used to convert ADP to ATP.
• C. The link is a proton gradient created by the movement of electrons.
• D. The energy from ATP is used to pump protons to generate more electrons.

Answer: (C)

The link between electron transport and ATP synthesis is chemiosmotic coupling: as electrons move through the electron transport chain, their energy is used to pump protons across the inner mitochondrial membrane, creating a proton gradient (proton motive force). This stored energy drives protons back through ATP synthase, turning ADP and inorganic phosphate into ATP. So ATP production is powered by the electrochemical gradient generated by electron transport, not by a direct transfer of electrons to ADP, and not by some wireless transfer or by ATP pushing protons.

The link between electron transport and ATP synthesis is chemiosmotic coupling: as electrons move through the electron transport chain, their energy is used to pump protons across the inner mitochondrial membrane, creating a proton gradient (proton motive force). This stored energy drives protons back through ATP synthase, turning ADP and inorganic phosphate into ATP. So ATP production is powered by the electrochemical gradient generated by electron transport, not by a direct transfer of electrons to ADP, and not by some wireless transfer or by ATP pushing protons.