Student answer will be structured as a paragraph, or bullet point sentences, including at least five (but not restricted to) of the following points: hydrogens from reduced hydrogen carriers (FADH/NADH); hydrogens enter chain; hydrogen is split into protons and electrons; electron is passed to chain of electron carriers; protons remain in mitochondrial matrix; energy released from electron carrier chain used to pump protons from matrix into intermembrane space; concentration gradient formed between mitochondrial matrix and the intermembrane space; protons flow down this concentration gradient via ATP synthase; ATP synthase facilitates formation of ATP.