Where in stage 4 does the energy come from for the synthesis of ATP?

Question

1. the combination of hydrogen ions, electrons, and oxygen to form water
2. ATP synthase
3. the cytochromes
4. an electrochemical gradient
5. oxygen

Answer 1

The answer is 4) an electrochemical gradient. The electrochemical gradient is formed as protons are pumped out of the mitochondrial matrix into the intermembrane space as electrons are passed through Complex I and Complex I, III, and IV of the electron transport chain.