3. Cellular Respiration Cellular Respiration

4. All organisms need energy

5. Why do we need energy? To Grow To Move To Reproduce ETC.

6. All living things require energy to maintain homeostasis The ultimate source of energy is the SUN Autotrophs obtain energy directly from the sun – plants, algae, and photosynthetic bacteria Heterotrophs obtain their energy from food molecules – animals and human Source of Energy

7. Photosynthesis & respiration provide energy for lifePhotosynthesis & respiration provide energy for life PhotosynthesisPhotosynthesis –uses solar energy to produce Glucose/O 2 from CO 2 & H 2 O Cellular respirationCellular respiration –Uses O 2 and makes ATP Photosynthesis and Respiration

8. Plants cells make ATP during photosynthesis Cells of other organisms make ATP by breaking down food such as carbohydrates, fats and proteins ATP later provides energy for cellular work ( breathing, digestion of food, muscle movement etc. ) Making Energy (ATP)

9. Respiration provides energy from food

10. Catabolic Pathways and Production of ATP The breakdown of organic molecules is an EXERGONIC reactionThe breakdown of organic molecules is an EXERGONIC reaction FERMENTATION is a partial degradation of sugars that occurs without O 2FERMENTATION is a partial degradation of sugars that occurs without O 2 AEROBIC respiration uses organic molecules such as Carbohydrates, Fat, Protein, Nucleic Acid and O 2 -----  yields ATPAEROBIC respiration uses organic molecules such as Carbohydrates, Fat, Protein, Nucleic Acid and O 2 -----  yields ATP ANAEROBIC respiration uses compounds other than O 2ANAEROBIC respiration uses compounds other than O 2

11. Anaerobic Processes No oxygen is required for these processes.No oxygen is required for these processes. Includes glycolysis, the breakdown of glucose, and fermentation.Includes glycolysis, the breakdown of glucose, and fermentation. Some bacteria and yeast are examples of anaerobes.Some bacteria and yeast are examples of anaerobes. http://www.biol.vt.edu/research/images/C._perfringens_in_mac._jpg.jpg http://www.utoronto.ca/greenblattlab/images/a/yeast%201.jpg

12. GlucoseOxygen gasCarbon dioxide WaterEnergy Cellular Respiration uses oxygen and glucose to produce Carbon dioxide, water, and ATP.

13. O2O2 CO 2 BREATHING Lungs CO 2 O2O2 Bloodstream Muscle cells carrying out CELLULAR RESPIRATION Sugar + O 2  ATP + CO 2 + H 2 O Breathing and Cell Respiration are related

14. Burning glucose in an experiment Energy released from glucose (as heat and light) 100% Energy released from glucose banked in ATP “Burning” glucose in cellular respiration About 40% Gasoline energy converted to movement Burning gasoline in an auto engine 25% How efficient is cell respiration?

15. Cellular respiration includes both aerobic and anaerobic respiration but is often used to refer to aerobic respirationCellular respiration includes both aerobic and anaerobic respiration but is often used to refer to aerobic respiration Although carbohydrates, fats, and proteins are all consumed as fuel, it is helpful to trace cellular respiration with the sugar glucose:Although carbohydrates, fats, and proteins are all consumed as fuel, it is helpful to trace cellular respiration with the sugar glucose:

16. REDOX Reactions Oxidation and Reduction The transfer of electrons during chemical reactions releases energy stored in organic moleculesThe transfer of electrons during chemical reactions releases energy stored in organic molecules This released energy is ultimately used to synthesize ATPThis released energy is ultimately used to synthesize ATP

17. Redox Reactions Chemical reactions that transfer electrons between reactants are called oxidation-reduction reactions, or redox reactionsChemical reactions that transfer electrons between reactants are called oxidation-reduction reactions, or redox reactions In oxidation, a substance loses electrons, or is oxidized In oxidation, a substance loses electrons, or is oxidized In reduction, a substance gains electrons, or is reduced (the amount of positive charge is reduced)In reduction, a substance gains electrons, or is reduced (the amount of positive charge is reduced)

18. Redox reactions Oxidation-reductionOxidation-reduction OIL RIG (adding e- reduces + charge)OIL RIG (adding e- reduces + charge) Oxidation is e- loss; reduction is e- gainOxidation is e- loss; reduction is e- gain Reducing agent: e- donorReducing agent: e- donor Oxidizing agent: e- acceptorOxidizing agent: e- acceptor

19. becomes oxidized (loses electron) becomes reduced (gains electron)

20. The electron donor is called the reducing agentThe electron donor is called the reducing agent The electron receptor is called the oxidizing agentThe electron receptor is called the oxidizing agent In cellular respiration, glucose is oxidized and oxygen is reduced.In cellular respiration, glucose is oxidized and oxygen is reduced. becomes oxidized becomes reduced

21. NAD + and Electron Transport Chain In cellular respiration, glucose and other organic molecules are broken down in a series of stepsIn cellular respiration, glucose and other organic molecules are broken down in a series of steps Electrons from organic compounds are usually first transferred to NAD +, a coenzymeElectrons from organic compounds are usually first transferred to NAD +, a coenzyme As an electron acceptor, NAD + functions as an oxidizing agent during cellular respirationAs an electron acceptor, NAD + functions as an oxidizing agent during cellular respiration Each NADH (the reduced form of NAD + ) represents stored energy that is tapped to synthesize ATPEach NADH (the reduced form of NAD + ) represents stored energy that is tapped to synthesize ATP

22. Oxidizing agent in respiration NAD+ (nicotinamide adenine dinucleotide)NAD+ (nicotinamide adenine dinucleotide) Removes electrons from food (series of reactions)Removes electrons from food (series of reactions) NAD + is reduced to NADH Enzyme action: dehydrogenaseNAD + is reduced to NADH Enzyme action: dehydrogenase Oxygen is the eventual electron acceptorOxygen is the eventual electron acceptor

23. Electron Carriers (shuttle) Nicotinamide Adenine DinucleotideNicotinamide Adenine Dinucleotide (NAD + →NADH)(NAD + →NADH) FAD → FADH 2FAD → FADH 2

24. NADH passes the electrons to the electron transport chainNADH passes the electrons to the electron transport chain ½ O 2 pulls electrons down the chain and forms water½ O 2 pulls electrons down the chain and forms water The energy yielded is used to regenerate ATPThe energy yielded is used to regenerate ATP

25. What is ATP ? ATP stands for adenosine triphosphate Energy carrying molecule used by cells to fuel their cellular process ATP has – a nitrogen base adenine – a 5 carbon sugar ribose – and 3 phosphate (PO 4 ) groups

26. How ATP Works? Energy is stored in bondEnergy is stored in bond between the 2 nd and 3 rd between the 2 nd and 3 rd phosphate groups phosphate groups When the bond is broken,When the bond is broken, energy is released and ADP is formed energy is released and ADP is formed ATP re - forms when ADP binds to a phosphate groupATP re - forms when ADP binds to a phosphate group

27. ATP / ADP Cycle ATP is constantly used and remade in the cell.ATP is constantly used and remade in the cell. Energy is released or stored by breaking or making a phosphate bond.Energy is released or stored by breaking or making a phosphate bond. http://www.columbia.edu/cu/biology/courses/c2005/purves6/figure06-09.jpg

28. THREE stages: GLYCOLYSIS (happens in the cytoplasm) KREBS CYCLE or CITRIC ACID CYCLE (happens in the inner compartments of mitochondria) ELECTRON TRANSPORT CHAIN or ETC ( in the inner membrane of mitochondria) Summary: C 6 H 12 O 6 + 6 O 2  6 CO 2 + 6H 2 O + ATP Stages of Cellular Respiration

29. Steps of Glycolysis Energy - requiring steps –2 ATP added to glucose (6C) molecule to energize it –glucose split to 2 PGAL (3C) or G3P Energy - releasing steps –each PGAL splits into pyruvate (3C) molecules –producing ATP and NADH

30. Fig. 9-6-1 Substrate-level phosphorylation ATP Cytosol Glucose Pyruvate Glycolysis Electrons carried via NADH

31. Fig. 9-6-2 Mitochondrion Substrate-level phosphorylation ATP Cytosol Glucose Pyruvate Glycolysis Electrons carried via NADH Substrate-level phosphorylation ATP Electrons carried via NADH and FADH 2 Citric acid cycle

32. Fig. 9-6-3 Mitochondrion Substrate-level phosphorylation ATP Cytosol Glucose Pyruvate Glycolysis Electrons carried via NADH Substrate-level phosphorylation ATP Electrons carried via NADH and FADH 2 Oxidative phosphorylation ATP Citric acid cycle Oxidative phosphorylation: electron transport and chemiosmosis

33. The process that generates most of the ATP is called the oxidative phosphorylation because it is powered by redox reactionsThe process that generates most of the ATP is called the oxidative phosphorylation because it is powered by redox reactions It generates nearly 90% of the ATPIt generates nearly 90% of the ATP A smaller amount of ATP is formed in glycolysis and in the citric acid cycle by substrate-level phosphorylationA smaller amount of ATP is formed in glycolysis and in the citric acid cycle by substrate-level phosphorylation

34. Enzyme ADP P Substrate Enzyme ATP + Product

35. An Overview of Cellular Respiration

36. Glycolysis The first stage of cellular respiration & fermentation Occurs in the cytoplasm of the cell Anaerobic ( O 2 is not required) Breaks down glucose (6 Carbon) molecule into two pyruvic acid or pyruvate (3 Carbon) molecules It takes 2 ATP to jump – start the reactions

37. Steps of Glycolysis Energy - requiring steps –2 ATP added to glucose (6C) molecule to energize it –glucose split to 2 PGAL (3C) or G3P Energy - releasing steps –each PGAL splits into pyruvate (3C) molecules –producing ATP and NADH

38. End Product of Glycolysis Makes 4 ATP (2 ATPMakes 4 ATP (2 ATP used up, net yield is 2 ATP) used up, net yield is 2 ATP) 2 NADH & 2 molecules2 NADH & 2 molecules of pyruvate (pyruvic acid)of pyruvate (pyruvic acid) If O 2 is available to the cell - pyruvate moves intoIf O 2 is available to the cell - pyruvate moves into mitochondria mitochondria

39. End Products of Glycolysis Makes 4 ATP (2 ATPMakes 4 ATP (2 ATP used up, net yield is 2 ATP) used up, net yield is 2 ATP) 2 NADH & 2 molecules2 NADH & 2 molecules of pyruvate (pyruvic acid)of pyruvate (pyruvic acid) If O 2 is available to the cell - pyruvate moves intoIf O 2 is available to the cell - pyruvate moves into mitochondria mitochondria

40. NEEDS 2 ATP 1 GLUCOSE 2 NAD 4 ADP+4P RELEASES 2adp + 2p 2 PYRUVATE 2 NADh 4 ATP

41. Mitochondria A large organelle with doubleA large organelle with double membrane membrane –inner fold is called cristae –central cavity known as matrix Site of aerobic cellular respirationSite of aerobic cellular respiration –energy stored in glucose is used to make ATP

42. PREP REACTION (between glycolysis and citric acid cycle) Occurs in the inner compartment of the mitochondrion.Occurs in the inner compartment of the mitochondrion. 2 - Three carbon pyruvic acid is converted to 2 - Three carbon pyruvic acid is converted to 2 - Two carbon, acetyl CoA 2 CO 2 2 NADH

43. Prep Reaction Pyruvic acid from glycolysis in mitochondria – reacts with coenzyme A, to form acetyl coenzyme (2C) – in the process CO 2 and NADH are also produced

44. Krebs Cycle (Citric Acid Cycle) Occurs in the in the inner membrane of mitochondria Named after the biochemist Hans Krebs Kreb’s Cycle is also known as the Citric acid Cycle Requires 2 cycles in order to completely oxidize one molecule of glucose (2 acetyl CoA) Over all there are five intermediate chemical steps

45. Krebs Cycle (Citric Acid Cycle)

46. Results of Krebs Cycle Each turn of the cycle makes: –1 ATP, 3 NADH, 1 FADH 2, and 2CO 2 2 turns ( one for each pyruvate) makes: –2 ATP, 6 NADH, 2 FADH 2, and 4CO 2 CO 2 is a waste product that diffuses out of the cells NADH & FADH 2 move to the electron transport chain (ETC)

47. The Krebs Cycle Needs 2 FAD 6 NAD Pyruvate 2ADP + 2P RELEASES 2 FADH2 6 NADH CO22ATP

48. Electron Transport Chain Happens in the inner membraneHappens in the inner membrane Accepts electron from NADH and FADH 2Accepts electron from NADH and FADH 2 Electrons provide energy for active transport of H + from inner compartment to outer compartment forming a membrane potential.Electrons provide energy for active transport of H + from inner compartment to outer compartment forming a membrane potential.

51. H+ then pass down a concentration gradient providing energy for ATP synthase to attach a phosphate atom to ADP → ATP H+ then pass down a concentration gradient providing energy for ATP synthase to attach a phosphate atom to ADP → ATP Terminal electron acceptor is oxygen; thus H 2 O is a by-product. Terminal electron acceptor is oxygen; thus H 2 O is a by-product. Total 32 ATP are produced.Total 32 ATP are produced.

52. Electron Transport Chain electrons from NADH and FADH 2 are passed to many electron transport enzymes which form an electron transport chainelectrons from NADH and FADH 2 are passed to many electron transport enzymes which form an electron transport chain at the end of the chain, an enzyme combines electrons from the chain, H+ (hydrogen ions) from the cell, and O 2 (oxygen) to make H 2 O (water).at the end of the chain, an enzyme combines electrons from the chain, H+ (hydrogen ions) from the cell, and O 2 (oxygen) to make H 2 O (water). oxygen is the final electron accepter and is needed to obtain energy from NADH and FADH 2oxygen is the final electron accepter and is needed to obtain energy from NADH and FADH 2

53. Electron Transport chain Occurs on the CRISTAE of the mitochondria Occurs on the CRISTAE of the mitochondria

54. The Electron Transport chain Needs 2 FADH 2 10 NADH O2O2O2O2 ADP + P ReleasesFADNAD H2OH2OH2OH2O Up to 34 ATP

55. ATP Formation the mitochondria accepts electrons, while some enzymes pump hydrogen ions outside the inner membranethe mitochondria accepts electrons, while some enzymes pump hydrogen ions outside the inner membrane movement of hydrogen ions is what powers the making of ATPmovement of hydrogen ions is what powers the making of ATP the movement of a pair of electrons down the electron transport chain produces enough energy to make 3 ATP molecules from ADPthe movement of a pair of electrons down the electron transport chain produces enough energy to make 3 ATP molecules from ADP

56. ATP Formation the more H ions on the outside makes the outside more positively charged than the insidethe more H ions on the outside makes the outside more positively charged than the inside the difference in the charges gives the energy needed to make ATP from ADPthe difference in the charges gives the energy needed to make ATP from ADP the mitochondrion membrane lets the enzymes pump ions out, but won’t let them come back inthe mitochondrion membrane lets the enzymes pump ions out, but won’t let them come back in

57. Electron Transport Chain

58. Electron Transfer Phosphorylation Electron transfer sets up H + ion gradients H + concentration gradient provides energy to make ATP from ADP and P i Making ATP by adding P i to ADP is called phosphorylation Each time one electron passes to oxygen (O 2 ) – 3 ATP are produced for each NADH – 2 ATP are produced for each FADH 2

59. Electron Transport Chain Cytochromes carry electron carrier molecules (NADH & FADH2) down to oxygenCytochromes carry electron carrier molecules (NADH & FADH2) down to oxygen Chemiosmosis: energy coupling mechanismChemiosmosis: energy coupling mechanism

60. ATP Synthase A channel protein in the inner mitochondrial membrane Allows H + to diffuse down their concentration gradient, back into the inner compartment This flow of H + drives the formation of ATP from ADP & unbound phosphate (P i ) –oxidative phosphorylation

61. Final ATP Tally StageNADHFADH2 ATP Yield Glycolysis22 Pyruvic acid conversion 2 Krebs cycle 622 ETC1032-34 Loss due to active transport -2 Total ATP 36-38

62. Summary of Energy Harvest

63. Phosphorylation in Animal Cells In cytoplasm (1)In cytoplasm (1) In mitochondria (2, 3 & 4)In mitochondria (2, 3 & 4)

64. Other Food Pathways 1.Carbohydrates 2.Lipids 3.Proteins

65. Anaerobic Respiration Using Glycolysis → 2 ATP 1. Lactic Acid Fermentation - Glucose → Pyruvic Acid → Lactic Acid –During periods of strenuous exercise, lactic acid may build up in muscles causing cramping. –By bacteria in food production…sour cream, yogurt, sauerkraut, pickles, kimchee

66. 2. Ethanol Fermentation Glucose → Pyruvic Acid → Acetaldehyde → Ethanol By yeast in ethanol production of beer and wine. CO 2 produced causes bread to rise

67. Related metabolic processes Fermentation:Fermentation: 1. Alcohol: From pyruvate to ethanol1. Alcohol: From pyruvate to ethanol 2. Lactic acid: From pyruvate to lactate2. Lactic acid: From pyruvate to lactate Facultative anaerobes (yeast/bacteria)Facultative anaerobes (yeast/bacteria)

68. Two types of Fermentation Alcoholic Fermentation – in yeast Lactic acid Fermentation –in some bacteria and animal cell Steps that follow glycolysis serve only to regenerate NAD +

69. Anaerobic extraction of energy from organic molecules –does not require oxygen Takes place only in cytoplasm Yields only 2 ATP Do not break down glucose completely to CO 2 and water The ultimate electron acceptor is an organic molecule and not oxygen Fermentation

70. Lactic Acid Fermentation Carried out by certain bacteria and animal cell Certain bacteria utilized in food production (sour cream, yogurt, pickles)

71. Alcoholic Fermentation Utilized by yeast in the absence of oxygen CO 2 produced by fermentation allows bread to rise Ethanol utilized in production of beer and wine

72. Anaerobic respiration GlucoseGlycolysis 2 Pyruvic acid Alcohol + CO 2 Lactic acid Alcohol + CO 2 Lactic acid

73. Chemiosmosis Energy released creates a proton gradient across the mitochondrial membrane Proton gradient stores potential energy that can be used to phosphorylate ADP Process is driven by a proton gradient (ATP synthesis proceeds as protons diffuse back across the membrane)

75. Metabolism Catabolic Processes Energy releasing reactions Breakdown of large molecules to small molecules Ingested food is the source of molecules Anabolic Processes Energy requiring reactions Join small molecules to form large molecules Synthesize molecules essential to life

76. How Important is Oxygen?? without oxygen, electron transport can happen, but the Krebs Cycle will stop, and ATP production will also stopwithout oxygen, electron transport can happen, but the Krebs Cycle will stop, and ATP production will also stop if our bodies don’t get enough oxygen, then they’ll try to work from the oxygen from glycolysisif our bodies don’t get enough oxygen, then they’ll try to work from the oxygen from glycolysis oxygen has a major role in the mitochondria of a celloxygen has a major role in the mitochondria of a cell

77. Comparison photosynthesis and respiration can be thought of as opposite reactionsphotosynthesis and respiration can be thought of as opposite reactions photosynthesis gives energy, respiration takes energyphotosynthesis gives energy, respiration takes energy respiration and photosynthesis’ equations are reverse of each otherrespiration and photosynthesis’ equations are reverse of each other the products of photosynthesis are the reactants for the breaking down of glucosethe products of photosynthesis are the reactants for the breaking down of glucose