Answers:
High-energy electrons from NADH and FADH2, are passed into and along the electron transport chain .
The energy from the electrons moving down the chain is used to move H+ ions across the inner membrane .
H+ ions build up in the intermembrane space, making it positively charged and making the matrix negatively charged.
In the inner membrane, H+ ions move through channels of ATP synthase .
The ATP synthase uses the energy from the moving ions to combine ADP and phosphate, forming high-energy ATP .