1. Recap: structure of ATP P P P riboseguanineinorganic phosphate deoxyribosethymine organic phosphate nicotinamidecytosineadenineflavine

2. Recap: where in the cell? 1.Glycolysis 1.Phosphorylation 2.Oxidation 2.Link reaction 3.Krebs cycle 4.Oxidative phosphorylation

3. Recap: glycolysis

4. Recap: link reaction

5. Recap: Krebs cycle

6. Enzymes Glycolysis: –Phosphofructokinase Krebs cycle: –Decarboxylases –Dehydrogenases

7. Regulatory enzymes glucose phosphofructokinase enzyme pyruvate Krebs cycle ↑ ATP ↑ citrate ↑ ADP ↓ ATP ↓ citrate

9. How much ATP has been produced? Glycolysis: Link reaction: Krebs cycle: Is this enough???

10. The electron transport chain

11. 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

12. 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

13. 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!

14. How much ATP? Stage of respirationMolecules producedNumber of ATP molecules Glycolysis Link reaction (x2) Krebs cycle (x2) Total ATP =

15. Anaerobic respiration glucose pyruvate carbon dioxide + ethanal ethanol lactic acid

16. 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?