Respiration

• Reduced NAD and reduced FAD are oxidised to release protons and high-energy electrons
• The electrons are passed to the electron transfer chain in the inner mitochondrial membrane
• Electrons are passed along a chain of electron carriers
• Energy is released from these electrons to actively pump protons against their electrochemical gradient into the intermembrane space
• The energy for pumping protons is released from high-energy electrons and not ATP
• Protons move by facilitated diffusion through a channel in ATP synthase in the inner mitochondrial membrane down their electrochemical gradient back to the matrix (chemiosmosis)
• This movement of protons releases energy that causes ATP synthase to change its tertiary structure and catalyse the formation of ATP from ADP and Pi
• Most of the ATP from aerobic respiration is made through this process
• Electrons, along with protons, are used to reduce oxygen to water
• Oxygen is the final electron acceptor of the electron transfer chain in oxidative phosphorylation