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Announcements

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    1. Announcements My Pyramid extra credit project is due TODAY! You should have turned your labs in/made up your quizzes already. Cell/Pedigree extra credit projects are due next week.

    2. Announcements FINAL EXAM cumulative 2 hrs starts at 11am in this room you can use a periodic table and calculator NO CELL PHONES!

    3. Announcements Celebrate the end of Bio 099 at the Outback Steakhouse next Saturday from 2-4pm Heres the address: 615 Bel Air Rd Bel Air MD 21014

    4. An overview of Metabolism Bio 099 December 8, 2007

    5. Metabolism Metabolism is all the chemical reactions that occur in a living organism.

    6. Catabolism Catabolism is the breakdown or digestion of organic molecules.

    7. What molecules does the cell break down for energy? Usually fats and carbohydrates are the fuel of choice Triglycerides = fatty acids + glycerol Glycogen = monosaccharides

    8. Glycogen most abundant storage of carbohydrate a branched chain of glucose molecules

    9. Triglycerides most abundant storage of lipids primarily of fatty acids

    10. Proteins most abundant organic components in body perform many vital cellular functions

    11. Metabolism Handout

    12. Tools for making ATP To survive cells need to make ATP. For ATP synthesis the following are required: oxygen

    13. Tools for making ATP To survive cells need to make ATP. For ATP synthesis the following are required: oxygen nutrients/vitamins

    14. Tools for making ATP To survive cells need to make ATP. For ATP synthesis the following are required: oxygen nutrients/vitamins mitochondria

    15. Tools for making ATP To survive cells need to make ATP. For ATP synthesis the following are required: oxygen nutrients/vitamins mitochondria enzymes

    16. Why are catabolic reactions necessary for the cell? To release energy for anabolic reactions!

    17. Anabolism Anabolism is the production of new organic molecules using cellular energy (ATP).

    18. Why is anabolism necessary? Metabolic Turnover: The cell needs energy to periodically replace its components. Growth and Division: In order to grow and divide a cell needs energy. Special Processes: Depending on the specific cell type, various functions require energy. For example: muscle cell contraction requires energy. Nutrient Pool: A cell keeps a reserve storage of nutrients, just in case

    19. Catabolism: Aerobic Cellular Respiration

    20. Aerobic Cellular Respiration: generating ATP for the cell Glycolysis Krebs cycle (TCA) Electron transport chain

    21. Aerobic Cellular Respiration Glycolysis Krebs cycle (TCA) Electron transport chain

    22. Mechanisms of ATP synthesis substrate-level phosphorylation occurs during glycolysis and Krebs cycle ADP + P ? ATP oxidative phosphorylation occurs during the electron transport chain formation of a proton (H+) gradient across the inner mitochondrial membrane provides potential energy to make ATP

    23. Oxidation-reduction (redox) reactions are important in metabolism Oxidation: a molecule is oxidized when it loses electrons. Reduction: a molecule is reduced when it gains electrons.

    24. Example of a redox reaction: NAD+ Nicotinamide adenine dinucleotide (NAD+) is a coenzyme that carries electrons to be used in the electron transport chain. NAD+ is made from the vitamin niacin.

    25. Example of a redox reaction: FAD+ flavin adenine dinucleotide (FAD) is a coenzyme that carries electrons to be used in the electron transport chain. FAD contains riboflavin (vitamin B2).

    26. generates ATP by breaking down sugar C6H12O6 + 6O2? 6H2O + 6CO2 = 36 ATP + heat 1 molecule of glucose nets 36 molecules of ATP Carbohydrate Catabolism

    27. Glucose must first get into the cell insulin binds to its receptor to tell the cell glucose is coming and to add glucose transporter proteins to the membrane. glucose is transported into the cell through facilitated diffusion

    28. Carbohydrate Metabolism Glycolysis: always happens first.

    29. Glycolysis

    30. Glycolysis

    31. Glycolysis

    32. Glycolysis

    33. Glycolysis

    34. Glycolysis

    35. Glycolysis

    36. Glycolysis

    37. Glycolysis

    38. Glycolysis: Take home message ATP is used in 2 reactions at the beginning of glycolysis:

    39. Glycolysis: Take home message ATP is used in 2 reactions at the beginning of glycolysis: to keep glucose in the cell to make the molecule that is then broken in half

    40. Glycolysis: Take home message ATP is used in 2 reactions at the beginning of glycolysis: to keep glucose in the cell to make the molecule that is then broken in half 4 ATP and 2 NADH are generated in the last half of glycolysis,

    41. Glycolysis: Take home message ATP is used in 2 reactions at the beginning of glycolysis: to keep glucose in the cell to make the molecule that is then broken in half 4 ATP and 2 NADH are generated in the last half of glycolysis 2 pyruvate molecules are generated from glycolysis.

    42. Carbohydrate Metabolism Glycolysis Pyruvic acid transition

    43. The fate of pyruvic acid In the absence of oxygen (anaerobic)

    44. The fate of pyruvic acid By the way this is also how we make alcohol from sugar: fermentation

    45. The fate of pyruvic acid In the presence of oxygen (aerobic)

    46. The fate of pyruvic acid In the presence of oxygen (aerobic)

    47. The fate of pyruvic acid In the presence of oxygen (aerobic)

    48. Carbohydrate Metabolism Glycolysis Pyruvic acid transition Krebs cycle

    49. Krebs Cycle (TCA, citric) Acetyl CoA combines with oxaloacetic acid to form citric acid

    50. Krebs Cycle (TCA, citric) Acetyl CoA combines with oxaloacetic acid to form citric acid as the cycle continues carbons are removed, forming CO2 and NAD/FAD are reduced to NADH/FADH (electron carriers)

    51. Krebs Cycle (TCA, citric) Acetyl CoA combines with oxaloacetic acid to form citric acid as the cycle continues carbons are removed, forming CO2 and NAD/FAD are reduced to NADH/FADH (coenzymes and electron carriers) 1 ATP molecule is made via substrate-level phosphorylation

    52. The Krebs Cycle Overall Products Coenzyme A 2 CO2 3 NADH FADH2 ATP Overall Reactants Acetyl-CoA 3 NAD+ FAD ADP and Pi

    53. What do you get when 1 glucose molecule is broken down via aerobic respiration? Glycolysis: 2 ATP via substrate-level phosphorylation 2 NADH2 Transition Reaction (pyruvate to acetyl CoA): 2 NADH2 Krebs Cycle: 6 NADH2 2 FADH2 2 ATP

    54. Metabolism Handout: note that lipid and protein break-down also form molecules that enter the Krebs cycle.

    55. Electron Transport Chain (ETC) Oxygen must be present! Finally we will see the fate of the coenzymes (NADH, FADH2).

    56. the fate of NADH2 and FADH NADH and FADH drop off H ions (and e-) at the ETC in the mitochondria.

    57. Electron shuttling e- are shuttled through a sequence of membrane proteins (electron carriers).

    58. H+ pumping this provides energy to pump H ions against their concentration gradient

    59. Electron carriers and H+ pumps Two types of proteins in the inner mitochondrial membrane shuttle e- and/or pump H+.

    60. Electron carriers and H+ pumps Two types of proteins in the inner mitochondrial membrane shuttle e- and/or pump H+. complexes I-IV

    61. Cytochromes Two types of proteins in the inner mitochondrial membrane shuttle e- and/or pump H+. complexes I-IV cytochromes Cytochromes are proteins with heme groups that require Fe, S and Cu.

    62. Electron carriers and H+ pumps Two types of proteins in the inner mitochondrial membrane shuttle e- and/or pump H+. complexes I-IV cytochromes Cytochromes are proteins with heme groups that require Fe, S and Cu.

    63. Electron carriers and H+ pumps Two types of proteins in the inner mitochondrial membrane shuttle e- and/or pump H+. complexes I-IV cytochromes Cytochromes are proteins with heme groups that require Fe, S and Cu. Coenzyme Q is not a protein, but still carries e-.

    64. Oxidative Phosphorylation: ADP ? ATP The H+ gradient creates energy to power the ATP synthase complex.

    65. Oxidative Phosphorylation: ADP ? ATP The H+ gradient creates energy to power the ATP synthase complex. As H+ rush back into the matrix through the ATP synthase protein, ADP is phosphorlyated

    66. Oxidative Phosphorylation: ADP ? ATP The H+ gradient creates energy to power the ATP synthase complex. As H+ rush back into the matrix through the ATP synthase protein, ADP is phosphorlyated This process is also known as chemiosmosis

    67. ETC animation

    68. Oxidative Phosphorylation: how many ATP are made? NADH from glycolysis: 2 ATP in electron transport chain exception is cardiac muscle = 3 ATP in ETC NADH from pyruvate transition reaction: 3 ATP in electron transport chain NADH from Krebs cycle: 3 ATP in electron transport chain FADH2 from Krebs cycle: 2 ATP in electron transport chain

    69. Total ATP production from 1 molecule of glucose

    70. Total ATP production from 1 molecule of glucose

    71. Metabolism Handout: Now we will add in the side arrows.

    72. Storing carbohydrate energy: Glycogenesis Carried out in liver and muscle

    73. Utilizing stored energy: Glycogenolysis: breaking down glycogen to glucose carried out in liver

    74. making carbs from other sources: Gluconeogenesis Formation of glucose from fatty acids and amino acids basically glycolysis in reverse happens in the liver

    75. Metabolism Handout: Now we will add in the side arrows.

    76. Lipid Metabolism: digestion fats are digested, absorbed and put into chylomicrons (large lipoprotiens).

    77. Lipid Metabolism: digestion fats are digested, absorbed and put into chylomicrons (large lipoproteins). Chylomicrons enter the blood stream where triglycerides are extracted. The remnant of the chylomicron goes to the liver

    78. Metabolism Handout: Now we will add in the side arrows.

    79. Lipid Metabolism: digestion The triglycerides are broken down further in the blood to free fatty acids + glycerol.

    80. The fate of glycerol glycerol is converted to glyceraldehyde-3-phosphate G-3-P enters glycolysis and then goes through Krebs cycle and the ETC.

    81. The fate of free fatty acids: Beta-oxidation Fatty acids are broken down into 2 carbon acetic acid fragments. the acetic acid is converted to acetyl-Co A, which enters the Krebs cycle and then ETC

    82. Storing fat: Lipogenesis

    83. Utilizing stored energy: lipolysis Breakdown of lipids

    84. Ketogenesis If you are on a low-carb diet, starving yourself, or diabetic: oxaloacetic acid (from breakdown of glucose) levels decline and slow down the turning of the Krebs cycle acetyl Co-A (from fatty acid breakdown) accumulates and the liver converts it to ketone bodies Ketone bodies are released into the blood so they can be eliminated by the kidneys excess ketones in blood = ketoacidosis

    85. Metabolism Handout: Now we will add in the side arrows.

    86. Protein Metabolism Generally, proteins are not used for energy because we need them for protein synthesis (essential amino acids)

    87. Overview of Catabolism glucose = glycolysis fatty acids = beta-oxidation amino acids = deamination

    88. Overview of Anabolism We talked about: Glycogenolysis Gluconeogenesis Lipogenesis Cells also use ATP to make proteins and nucleic acids.

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