1.Hydrogen atoms released from NADH and FADH as they are oxidised 2.Hydrogen atoms split into protons and electrons 3.Electrons move along the electron transport chain, losing energy at each carrier 4.Energy is used to pump protons into intermembrane space forming an electrochemical gradient 5.Protons move down electrochemical gradient back to matrix via ATP synthase 6.Movement of protons drives synthesis of ATP from ADP and inorganic phosphate 7.Protons, electrons and oxygen combine to form water, the final electron acceptor
Evidence for chemiosmosis 1.pH of intermembrane space is lower than pH of matrix –Proton gradient exists between intermembrane space and matrix 2.Artificial vesicles created with proton pump proteins resulted in ↓ pH in vesicle –Proton gradient can be used to synthesise ATP 3.Mitochondria in pH8 solution produced no ATP –Proton gradient can be used by mitochondria to make ATP 4.Uncouplers destroyed proton gradient in mitochondria –Proton gradient is required by mitochondria to make ATP
How much ATP? Oxidative phosphorylation makes ATP using energy from NADH and FADH 1 NADH → 2.5 ATP 1 FADH → 1.5 ATP More cutbacks: In 1997 1 NADH → 3 ATP and 1 FADH → 2 ATP!
How much ATP? Stage of respirationMolecules producedNumber of ATP molecules Glycolysis Link reaction (x2) Krebs cycle (x2) Total ATP =
Aerobic and anaerobic respiration Aerobic Where? Is oxidation complete? What are the waste products? How much energy? Anaerobic Where? Is oxidation complete? What are the waste products? How much energy?