1. Cellular Respiration

2. Introduction  Before food can be used to perform work, its energy must be released through the process of respiration.  Two main types of respiration exist in living things. Both begin with glycolysis.  Glycolysis: a process by which one glucose molecule is broken down into two pyruvic acid molecules.  Fermentation (anaerobic respiration): pyruvic acid is broken down without the use of oxygen  Oxidative Respiration (aerobic respiration): pyruvic acid is metabolized using oxygen

3. Glucose Glycolysis Krebs cycle Electron transport Fermentation (without oxygen) Alcohol or lactic acid Aerobic Respiration Anaerobic Respiration

5. Glycolysis

6.  Glycolysis occurs in the cytoplasm.  It does not require oxygen.  Each of its four stages is catalyzed by a specific enzyme.

7. Glycolysis

8. Glucose ATP ADP + P PGAL PGAL + P Pyruvic Acid NADH + H + 2 ADP + 2 P 2 ATP NAD + + 2 H + + 2 e - NAD + + 2 H + + 2 e -

10. Anaerobic Respiration Fermentation

12. Fermentation (Anaerobic Respiration)  Fermentation is the breakdown of pyruvic acid without the use of oxygen.  Glycolysis + Fermentation = Anaerobic Respiration  The metabolism of pyruvic acid during fermentation does not produce any ATP. Instead, the function of fermentation is to break down pyruvic acid and regenerate NAD+ for reuse in glycolysis.

13. Pyruvic Acid NADH + H + NAD + + 2 H + + 2 e - Lactic Acid Pyruvic Acid NADH + H + NAD + + 2 H + + 2 e - Ethyl Alcohol (Ethanol) CO 2 Lactic Acid Fermentation Alcoholic Fermentation To Glycolysis

15. Aerobic Respiration Oxidative Respiration

17. Aerobic Respiration  The result of glycolysis and aerobic respiration is shown by the reaction:  C 6 H 12 O 6 + 6 O 2 → 6 H 2 O + 6 CO 2 + 38 ATP  Aerobic respiration occurs in the mitochondria  outer and inner membrane  matrix: dense solution enclosed by inner membrane  cristae: the folds of the inner membrane that house the electron transport chain and ATP synthase  Steps:  Conversion of Pyruvic Acid  Kreb’s Cycle  Electron Transport Chain

18. Structure of Mitochondrion

19. Kreb’s Cycle  The Krebs Cycle is the central biochemical pathway of aerobic respiration. It is named after its discoverer, Sir Hans Krebs. Because citric acid is formed in the process, it is also known as the Citric Acid Cycle.

20. Conversion of PA Kreb’s Cycle

21. NADH + H + NAD + CoA NAD + NADH + H + NAD + NADH + H + FAD FADH 2 ATP ADP + P CO 2 C Pyruvic Acid CCC Acetyl-CoA CC Citric Acid CCCCCC CO 2 C Ketoglutaric Acid CCCCC Succinic Acid CCCC CO 2 C Malic Acid CCCC Oxaloacetic Acid CCCC

23. Electron Transport Chain  Glycolysis, the conversion of PA to acetyl- CoA, and the Krebs Cycle complete the breakdown of glucose.  Up to this point:  4 ATP (2 from glycolysis, 2 from Krebs)  10 NADH + H+ (2 from glycolysis, 2 from the conversion of PA, 6 from Krebs)  2 FADH 2 (from Krebs)

24. Electron Transport Chain  NADH + H + and FADH 2 carry electrons to an electron transport chain, where additional ATP is produced.  10 NADH 30 ATP  2 FADH2 4 ATP

25. Electron Transport Chain

26. Intermembrane Space Matrix Inner Membrane NAD + FAD NADH + H + FADH 2

27. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

28. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

29. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

30. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

31. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

32. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

33. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

34. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

35. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

36. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

37. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

38. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

39. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

40. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

41. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

42. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

43. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

44. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

45. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

46. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

47. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

48. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2

49. Intermembrane Space Matrix Inner Membrane NADH + H + NAD + FAD FADH 2 ~e~e ADP + P ATP

50. Electron Transport Hydrogen Ion Movement ATP Production ATP synthase Channel Inner Membrane Matrix Intermembrane Space

51. Energy Yield

52.  Aerobic respiration produces a maximum of 38 ATP.  2 ATP from Glycolysis  2 ATP from Krebs  34 ATP from ETC  Reasons why ATP yield can be less than 38:  Sometimes energy is required to transport NADH + H + formed by glycolysis from the cytoplasm through the inner mitochondrial membrane.  Some H + in chemiosmosis may leak through the membrane.

53. Energy Yield

54.  Aerobic Respiration is generally 19 times more efficient than anaerobic respiration.  The ATP produced during aerobic respiration represents about 1/2 of the energy stored in a molecule of glucose.