1. Respiration A level Biology Sutton Girls Grammar school

2. Respiration When oxygen is available, aerobic respiration can take place Aerobic respiration has 4 stages: Glycolysis The link reaction The Krebs’ cycle Oxidative phosphorylation When there is no oxygen available, anaerobic respiration takes place

3. GlycolysisGlucose Glucose is the substrate

4. GlycolysisGlucose ATP Glucose is phosphorylated

5. GlycolysisGlucose ATP Glucose 6 P Forming G6P

6. GlycolysisGlucose ATP Glucose 6 P ATP G6P is phosphorylated

7. GlycolysisGlucose ATP Glucose 6 P ATP Fructose 1,6 P Forming F1,6P

8. GlycolysisGlucose ATP Glucose 6 P ATP Fructose 1,6 P 3-C sugar F1,6P splits to form two 3 carbon sugars

9. GlycolysisGlucose ATP Glucose 6 P ATP Fructose 1,6 P 3-C sugar PyruvatePyruvate These are converted to pyruvate

10. GlycolysisGlucose ATP Glucose 6 P ATP Fructose 1,6 P 3-C sugar PyruvatePyruvate 2ATP Giving out 2 ATP…

11. GlycolysisGlucose ATP Glucose 6 P ATP Fructose 1,6 P 3-C sugar PyruvatePyruvate 2ATP 2H … and 2H + each

12. GlycolysisGlucose ATP Glucose 6 P ATP Fructose 1,6 P 3-C sugar PyruvatePyruvate 2ATP 2H Net yield then is: 2ATP 2x (2H + ) Glycolysis occurs in the cytoplasm.

13. The link reaction Pyruvate is converted to acetyl coenzyme A Pyruvate Acetyl coenzyme A

14. The link reaction Giving out 2H + … Pyruvate Acetyl coenzyme A 2H

15. The link reaction … and CO 2 Pyruvate Acetyl coenzyme A 2HCO 2

16. The link reaction This occurs inside the mitochondria. Pyruvate Acetyl coenzyme A 2HCO 2

17. The link reaction Net yield then is: 2x 2H + 2 CO 2 Pyruvate Acetyl coenzyme A 2HCO 2

18. The Krebs’ cycle In the matrix of the mitochondrion: Acetyl coenzyme A

19. The Krebs’ cycle Acetyl CoA combines with a 4C acid… Acetyl coenzyme A Four carbon acid

20. The Krebs’ cycle … forming the 6 carbon compound citrate: Acetyl coenzyme A Citrate (6C) Four carbon acid

21. The Krebs’ cycle The citrate is decarboxylated to a 5C acid: Acetyl coenzyme A Citrate (6C) Four carbon acid Five carbon acid

22. The Krebs’ cycle … releasing CO 2 … Acetyl coenzyme A CO 2 Citrate (6C) Four carbon acid Five carbon acid

23. The Krebs’ cycle … and 2H + Acetyl coenzyme A 2H CO 2 Citrate (6C) Four carbon acid Five carbon acid

24. The Krebs’ cycle The 5C acid is decarboxylated - reforming the 4C acid: Acetyl coenzyme A 2H CO 2 Citrate (6C) Four carbon acid Five carbon acid

25. The Krebs’ cycle Releasing another CO 2 Acetyl coenzyme A 2H CO 2 Citrate (6C) Four carbon acid Five carbon acid CO 2

26. The Krebs’ cycle … three 2H + Acetyl coenzyme A 2H CO 2 Citrate (6C) Four carbon acid Five carbon acid CO 2 2H

27. The Krebs’ cycle … and an ATP Acetyl coenzyme A 2H CO 2 Citrate (6C) Four carbon acid Five carbon acid CO 2 2H ATP

28. The Krebs’ cycle Net yield: 2ATP 4CO 2 8x 2H + Acetyl coenzyme A 2H CO 2 Citrate (6C) Four carbon acid Five carbon acid CO 2 2H ATP

29. Oxidative phosphorylation The 2H+ reduces NAD to NADH + + H + 2H NAD FAD carrier carrier

30. Oxidative phosphorylation The 2H+ reduces NAD to NADH + + H + 2H NADHH FAD carrier carrier

31. Oxidative phosphorylation FAD is then reduced… 2H NAD FADHH carrier carrier

32. Oxidative phosphorylation … generating ATP 2H ATP NAD FADHH carrier carrier

33. Oxidative phosphorylation Two more carriers are reduced… 2H ATP NAD FAD carrier carrier

34. Oxidative phosphorylation … generating more ATP. 2H ATP NAD FAD carrier carrier

35. Oxidative phosphorylation The 2H + is then passed onto O 2 2H O2O2 ATP NAD FAD carrier carrier

36. Oxidative phosphorylation Which forms water. 2H H2OH2O O2O2 ATP NAD FAD carrier carrier

37. Oxidative phosphorylation This occurs across the inner membrane of the mitochondria – ATP synthesised using the stalked particles. 2H H2OH2O O2O2 ATP NAD FAD carrier carrier

38. Oxidative phosphorylation Some of the 2H + reduces FAD 2H H2OH2O O2O2 NAD FAD carrier carrier

39. Oxidative phosphorylation So only produces 2ATP. 2H H2OH2O O2O2 NAD FAD carrier carrier ATP

40. Summary Glycolysis 6 H 2 O 2(2H + ) 6 O 2 2 ATP Glucose Link reaction Krebs’ cycle 2 CO 2 4 CO 2 2(2H + ) 2 ATP 4 ATP 6 ATP 4 ATP 18 ATP6(2H + )

41. Anaerobic respiration In the absence of oxygen anaerobic respiration takes placeGlucose

42. Anaerobic respiration Glucose is phosphorylated to two 3-C sugars 2ATP 3-C sugar Glucose

43. Anaerobic respiration These are then converted to pyruvate, generating ATP & 2H + 2(2H + ) 2 ATP PyruvatePyruvate 3-C sugar 2 ATP 2(2H + ) Glucose

44. Anaerobic respiration In yeast the pyruvate is decarboxylated to ethanal: 2(2H + ) 2 ATP CO 2 PyruvatePyruvate 2ATP 3-C sugar CO 2 2 ATP 2(2H + ) Glucose Ethanal Ethanal

45. Anaerobic respiration … and then converted to ethanol – using the 2H + from the previous stage. 2(2H + ) 2 ATP CO 2 PyruvatePyruvate 2ATP 3-C sugar CO 2 2 ATP 2(2H + ) EthanolEthanol Glucose Ethanal Ethanal

46. Anaerobic respiration Net production is: 2ATP 2CO 2 2 ethanol 2(2H + ) 2 ATP CO 2 PyruvatePyruvate 2ATP 3-C sugar CO 2 2 ATP 2(2H + ) EthanolEthanol Glucose Ethanal Ethanal

47. Anaerobic respiration In animals, the pyruvate is converted to lactate: 2(2H + ) 2 ATP PyruvatePyruvate 3-C sugar 2 ATP 2(2H + ) LactateLactate Glucose

48. Anaerobic respiration … using the 2H + again: 2(2H + ) 2 ATP PyruvatePyruvate 3-C sugar 2 ATP 2(2H + ) LactateLactate Glucose

49. Anaerobic respiration Net production is: 2ATP 2 lactate 2(2H + ) 2 ATP PyruvatePyruvate 3-C sugar 2 ATP 2(2H + ) LactateLactate Glucose