1. End Show Slide 1 of 39 Copyright Pearson Prentice Hall Chapter 9: Cellular Respiration Section: 9-1 Chemical Pathways

2. Cellular Respiration

3. End Show Slide 3 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall 9-1 Chemical Pathways Food serves as a source of raw materials for the cells in the body and as a source of energy. Animal Plant Animal Cells Plant Cells Mitochondrion

4. Cellular Respiration CO 2 O2O2 O2O2 Bloodstream Muscle cells carrying out Cellular Respiration Breathing Glucose  O 2 CO 2  H 2 O  ATP Lungs

5. End Show Slide 5 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Both plant and animal cells carry out the final stages of cellular respiration in the mitochondria. Animal Cells Plant Cells Mitochondrion Outer membrane Intermembrane space Inner membrane Matrix

6. Cellular Respiration Cellular Respiration C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + energy (36 ATP)

7. What is Cellular Respiration Is a series of reactions where: fats, proteins, and carbohydrates, and (mostly) glucose, are broken down to make CO 2, water, and energy (ATP).

8. Where does Cellular Respiration take place in all cells?

9. Cellular Respiration Takes Place in the Mitochondria

10. Cellular Respiration A process by which mitochondria break down food molecules to produce ATP (36). Takes place in plants and animals Three stages of cellular respiration: Glycolysis Citric acid cycle or Kreb Cycle Electron transport chain

11. End Show Slide 11 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Chemical Energy and Food One gram of the sugar glucose (C 6 H 12 O 6 ), when burned in the presence of oxygen, releases 3811 calories of heat energy. A calorie is the amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius.

12. End Show 9-1 Chemical Pathways Slide 12 of 39 Copyright Pearson Prentice Hall Overview of Cellular Respiration What is cellular respiration?

13. End Show Slide 13 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Overview of Cellular Respiration Cytoplasm Pyruvic acid Mitochondrion Electrons carried in NADH Electrons carried in NADH and FADH 2 Glucose Glycolysis

14. End Show 9-1 Chemical Pathways Slide 14 of 39 Copyright Pearson Prentice Hall Overview of Cellular Respiration Cellular respiration is the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen.

15. End Show Slide 15 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Overview of Cellular Respiration The equation for cellular respiration is: 6O 2 + C 6 H 12 O 6 → 6CO 2 + 6H 2 O + Energy oxygen + glucose → carbon dioxide + water + Energy

16. End Show Slide 16 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Overview of Cellular Respiration Glycolysis takes place in the cytoplasm. The Krebs cycle and electron transport take place in the mitochondria. Cytoplasm Mitochondrion Glycolysis

17. End Show 9-1 Chemical Pathways Slide 17 of 39 Copyright Pearson Prentice Hall Glycolysis What happens during the process of glycolysis?

18. Stage One: Breakdown of Glucose Glycolysis Glucose is broken down to pyruvate (or pyruvic acid) during glycolysis, making some ATP.

19. Glycolysis 1 st stage of cellular respiration 1 st stage of cellular respiration Takes place in the cytoplasm of a cell Takes place in the cytoplasm of a cell Energy (ATP) is used to start glycolysis Energy (ATP) is used to start glycolysis Glucose is broken down into pyruvic acid Glucose is broken down into pyruvic acid Produces 2 ATP molecules for each molecule of glucose broken down Produces 2 ATP molecules for each molecule of glucose broken down

20. End Show Slide 20 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Glycolysis ATP Production At the beginning of glycolysis, the cell uses up 2 molecules of ATP to start the reaction. 2 ADP 4 ADP 4 ATP 2 Pyruvic acid 2 ATP Glucose

21. End Show Slide 21 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Glycolysis When glycolysis is complete, 4 ATP molecules have been produced. 2 ADP 4 ADP 4 ATP 2 ATP Glucose 2 Pyruvic acid

22. End Show Slide 22 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Glycolysis This gives the cell a net gain of 2 ATP molecules. 4 ADP 4 ATP Glucose 2 ADP 2 ATP 2 Pyruvic acid

23. End Show Slide 23 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Glycolysis NADH Production One reaction of glycolysis removes 4 high-energy electrons, passing them to an electron carrier called NAD +. Glucose 2 Pyruvic acid 4 ADP 4 ATP 2 ADP 2 ATP 2NAD +

24. End Show Slide 24 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Glycolysis Each NAD + accepts a pair of high-energy electrons and becomes an NADH molecule. Glucose 2 Pyruvic acid 4 ADP 4 ATP 2 ADP 2 ATP 2NAD + 2

25. End Show Slide 25 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Glycolysis The NADH molecule holds the electrons until they can be transferred to other molecules. To the electron transport chain 2NAD + 2 Pyruvic acid 4 ADP 4 ATP 2 ADP 2 ATP 2

26. End Show Slide 26 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Glycolysis The Advantages of Glycolysis The process of glycolysis is so fast that cells can produce thousands of ATP molecules in a few milliseconds. Glycolysis does not require oxygen.

27. Anaerobic Respiration Does NOT use oxygen Instead using the ATP in the cells “fermentation” takes place An example of this is the burning we feel in our muscles when we exercise for a long period of time Once we get more oxygen the burning lessens or disappears

28. Lactic Acid Fermentation Is one of the processes that supplies energy when O 2 is scarce (e.g., during strenuous activity) Is one of the processes that supplies energy when O 2 is scarce (e.g., during strenuous activity) Follows glycolysis and interrupts cellular respiration Follows glycolysis and interrupts cellular respiration Lactic acid is transferred from the muscle cells where it is produced during strenuous activity to the liver. Lactic acid is transferred from the muscle cells where it is produced during strenuous activity to the liver. Once in the liver it is converted into pyruvic acid. Once in the liver it is converted into pyruvic acid. Lactic acid build up in the muscles causes muscle fatigue and/or a burning sensation within muscles Lactic acid build up in the muscles causes muscle fatigue and/or a burning sensation within muscles

29. Alcoholic Fermentation Some types of bacteria and yeast cells convert pyruvic acid into carbon dioxide and ethyl alcohol. Some types of bacteria and yeast cells convert pyruvic acid into carbon dioxide and ethyl alcohol. In bread – yeast cells give off CO 2 which makes the bubbles in the dough that make it rise In bread – yeast cells give off CO 2 which makes the bubbles in the dough that make it rise

30. End Show Slide 30 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Fermentation When oxygen is not present, glycolysis is followed by a different pathway. The combined process of this pathway and glycolysis is called fermentation. Fermentation releases energy from food molecules by producing ATP in the absence of oxygen.

31. End Show Slide 31 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Fermentation During fermentation, cells convert NADH to NAD + by passing high-energy electrons back to pyruvic acid. This action converts NADH back into NAD +, and allows glycolysis to continue producing a steady supply of ATP. Fermentation does not require oxygen—it is an anaerobic process.

32. End Show 9-1 Chemical Pathways Slide 32 of 39 Copyright Pearson Prentice Hall Fermentation What are the two main types of fermentation?

33. End Show Slide 33 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Fermentation Alcoholic Fermentation Yeasts and a few other microorganisms use alcoholic fermentation, forming ethyl alcohol and carbon dioxide as wastes. The equation for alcoholic fermentation after glycolysis is: pyruvic acid + NADH → alcohol + CO 2 + NAD +

34. End Show Slide 34 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Fermentation Lactic Acid Fermentation In many cells, pyruvic acid that accumulates as a result of glycolysis can be converted to lactic acid. This type of fermentation is called lactic acid fermentation. It regenerates NAD + so that glycolysis can continue. The equation for lactic acid fermentation after glycolysis is: pyruvic acid + NADH → lactic acid + NAD +

35. End Show Slide 35 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Fermentation The first part of the equation is glycolysis.

36. End Show Slide 36 of 39 9-1 Chemical Pathways Copyright Pearson Prentice Hall Fermentation The second part shows the conversion of pyruvic acid to lactic acid.

37. End Show - or - Continue to: Click to Launch: Slide 37 of 39 Copyright Pearson Prentice Hall 9-1

38. End Show Slide 38 of 39 Copyright Pearson Prentice Hall 9-1 The raw materials required for cellular respiration are a.carbon dioxide and oxygen. b.glucose and water. c.glucose and oxygen. d.carbon dioxide and water.

39. End Show Slide 39 of 39 Copyright Pearson Prentice Hall 9-1 Glycolysis occurs in the a.mitochondria. b.cytoplasm. c.nucleus. d.chloroplasts.

40. End Show Slide 40 of 39 Copyright Pearson Prentice Hall 9-1 The net gain of ATP molecules after glycolysis is a.3 ATP molecules. b.2 ATP molecules. c.3 pyruvic acid molecules. d.4 pyruvic acid molecules

41. End Show Slide 41 of 39 Copyright Pearson Prentice Hall 9-1 Fermentation releases energy from food molecules in the absence of a.oxygen. b.glucose. c.NADH. d.alcohol.

42. End Show Slide 42 of 39 Copyright Pearson Prentice Hall 9-1 The first step in fermentation is always a.lactic acid production. b.the Krebs cycle. c.glycolysis. d.alcohol production.

43. END OF SECTION

44. End Show Slide 44 of 37 Copyright Pearson Prentice Hall Chapter 9: Cellular Respiration Section 9-2 The Krebs Cycle and Electron Transport

45. End Show 9-2 The Krebs Cycle and Electron Transport Slide 45 of 37 Copyright Pearson Prentice Hall 9-2 The Krebs Cycle and Electron Transport Oxygen is required for the final steps of cellular respiration. Because the pathways of cellular respiration require oxygen, they are aerobic.

46. End Show Slide 46 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall The Krebs Cycle What happens during the Krebs cycle?

47. End Show Slide 47 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall The Krebs Cycle During the Krebs cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.

48. Citric Acid or Kreb Cycle 2nd stage of cellular respiration 2nd stage of cellular respiration Takes place in the “matrix” of the mitochondria of a cell if O 2 is present Takes place in the “matrix” of the mitochondria of a cell if O 2 is present Pyruvic acid molecules move into the matrix of the mitochondria Pyruvic acid molecules move into the matrix of the mitochondria Citric Acid Cycle yields 1 ATP and 2 molecules of CO 2 Citric Acid Cycle yields 1 ATP and 2 molecules of CO 2

49. Stage Two: Production of ATP Krebs Cycle The Krebs cycle is a series of aerobic reactions that produce energy-storing molecules during aerobic respiration.

50. End Show Slide 50 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall The Krebs Cycle The Krebs cycle begins when pyruvic acid produced by glycolysis enters the mitochondrion.

51. End Show Slide 51 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall The Krebs Cycle One carbon molecule is removed, forming CO 2, and electrons are removed, changing NAD + to NADH.

52. End Show Slide 52 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall The Krebs Cycle Coenzyme A joins the 2-carbon molecule, forming acetyl-CoA.

53. End Show Slide 53 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall The Krebs Cycle Citric acid Acetyl-CoA then adds the 2-carbon acetyl group to a 4- carbon compound, forming citric acid.

54. End Show Slide 54 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall The Krebs Cycle Citric acid is broken down into a 5-carbon compound, then into a 4-carbon compound.

55. End Show Slide 55 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall The Krebs Cycle Two more molecules of CO 2 are released and electrons join NAD + and FAD, forming NADH and FADH 2

56. End Show Slide 56 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall The Krebs Cycle In addition, one molecule of ATP is generated.

57. End Show 9-2 The Krebs Cycle and Electron Transport Slide 57 of 37 Copyright Pearson Prentice Hall The Krebs Cycle The energy tally from 1 molecule of pyruvic acid is 4 NADH 1 FADH 2 1 ATP

58. End Show Slide 58 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall Electron Transport How are high-energy electrons used by the electron transport chain?

59. End Show Slide 59 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall Electron Transport The electron transport chain uses the high- energy electrons from the Krebs cycle to convert ADP into ATP.

60. End Show Slide 60 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall Electron Transport High-energy electrons from NADH and FADH 2 are passed along the electron transport chain from one carrier protein to the next.

61. End Show Slide 61 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall Electron Transport At the end of the chain, an enzyme combines these electrons with hydrogen ions and oxygen to form water.

62. End Show Slide 62 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall Electron Transport As the final electron acceptor of the electron transport chain, oxygen gets rid of the low-energy electrons and hydrogen ions.

63. End Show Slide 63 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall Electron Transport When 2 high-energy electrons move down the electron transport chain, their energy is used to move hydrogen ions (H + ) across the membrane.

64. End Show Slide 64 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall Electron Transport During electron transport, H + ions build up in the intermembrane space, so it is positively charged.

65. End Show Slide 65 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall Electron Transport The other side of the membrane, from which those H + ions are taken, is now negatively charged.

66. End Show Slide 66 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall Electron Transport ATP synthase The inner membranes of the mitochondria contain protein spheres called ATP synthases.

67. End Show Slide 67 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall Electron Transport As H + ions escape through channels into these proteins, the ATP synthase spins. ATP synthase Channel

68. End Show Slide 68 of 37 9-2 The Krebs Cycle and Electron Transport Copyright Pearson Prentice Hall Electron Transport As it rotates, the enzyme grabs a low-energy ADP, attaching a phosphate, forming high-energy ATP. ATP ATP synthase Channel

69. End Show 9-2 The Krebs Cycle and Electron Transport Slide 69 of 37 Copyright Pearson Prentice Hall The Totals Glycolysis produces just 2 ATP molecules per molecule of glucose. The complete breakdown of glucose through cellular respiration, including glycolysis, results in the production of 36 molecules of ATP.

70. End Show 9-2 The Krebs Cycle and Electron Transport Slide 70 of 37 Copyright Pearson Prentice Hall The Totals

71. End Show 9-2 The Krebs Cycle and Electron Transport Slide 71 of 37 Copyright Pearson Prentice Hall Comparing Photosynthesis and Cellular Respiration The energy flows in photosynthesis and cellular respiration take place in opposite directions.

72. End Show 9-2 The Krebs Cycle and Electron Transport Slide 72 of 37 Copyright Pearson Prentice Hall Comparing Photosynthesis and Cellular Respiration On a global level, photosynthesis and cellular respiration are also opposites. Photosynthesis removes carbon dioxide from the atmosphere and cellular respiration puts it back. Photosynthesis releases oxygen into the atmosphere and cellular respiration uses that oxygen to release energy from food.

73. End Show - or - Continue to: Click to Launch: Slide 73 of 37 Copyright Pearson Prentice Hall 9-2

74. End Show Slide 74 of 37 Copyright Pearson Prentice Hall 9-2 The Krebs cycle breaks pyruvic acid down into a.oxygen. b.NADH. c.carbon dioxide. d.alcohol.

75. End Show Slide 75 of 37 Copyright Pearson Prentice Hall 9-2 What role does the Krebs cycle play in the cell? a.It breaks down glucose and releases its stored energy. b.It releases energy from molecules formed during glycolysis. c.It combines carbon dioxide and water into high-energy molecules. d.It breaks down ATP and NADH, releasing stored energy.

76. End Show Slide 76 of 37 Copyright Pearson Prentice Hall 9-2 In eukaryotes, the electron transport chain is located in the a.cell membrane. b.inner mitochondrial membrane. c.cytoplasm. d.outer mitochondrial membrane.

77. End Show Slide 77 of 37 Copyright Pearson Prentice Hall 9-2 To generate energy over long periods, the body must use a.stored ATP. b.lactic acid fermentation. c.cellular respiration. d.glycolysis.

78. End Show Slide 78 of 37 Copyright Pearson Prentice Hall 9-2 Which statement correctly describes photosynthesis and cellular respiration? a.Photosynthesis releases energy, while cellular respiration stores energy. b.Photosynthesis and cellular respiration use the same raw materials. c.Cellular respiration releases energy, while photosynthesis stores energy. d.Cellular respiration and photosynthesis produce the same products.

79. END OF SECTION

80. Electron Transport Chain 3rd stage of cellular respiration 3rd stage of cellular respiration Takes place in the mitochondria of a cell Takes place in the mitochondria of a cell Similar to the Photosynthesis – electrons are passed from protein to protein to make ATP Similar to the Photosynthesis – electrons are passed from protein to protein to make ATP Some electrons are used to pump H+ ions into the center of the mitochondria to create more ATP Some electrons are used to pump H+ ions into the center of the mitochondria to create more ATP The final H+ electrons are the bottom of the electron transport chain combine with O 2 to create H 2 0 The final H+ electrons are the bottom of the electron transport chain combine with O 2 to create H 2 0

81. Comparing Photosynthesis and Cellular Respiration PhotosynthesisCellular Respiration Food synthesizedFood broken down Energy from sun stored in glucose Energy of glucose released Carbon dioxide taken inCarbon dioxide given off Oxygen given offOxygen taken it Produces sugarsProduces carbon dioxide and water Requires lightDoes not require light Occurs only in presence of chlorophyll Occurs in all living things