'The energy of electron transport (by the ETC) serves to move protons (hydrogen ions, H*) to the intermembrane space of the mitochondrion: How does this help the mitochondrion produce ATP?
This movement of protons sets Up the electrochemical gradient that drives ATP synthesis in the mitochondrion.
The protons receive electrons from the NAD+ and FAD that were accepted in glycolysis ad the citric acid cycle
The protons are transferred to oxygen in an energy-releasing reaction
The protons pick up electrons from the electron transport chain on their way through the inner mitochondrial membrane'