Chapter 7 metabolism and energy

1,408 views

Published on

kkk

Published in: Business, Education
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
1,408
On SlideShare
0
From Embeds
0
Number of Embeds
6
Actions
Shares
0
Downloads
75
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Chapter 7 metabolism and energy

  1. 1. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFundamentals ofAnatomy & PhysiologySIXTH EDITIONFredericH.MartiniChapter 7Metabolism and Energetics
  2. 2. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsLearning Objectives• Explain why cells need to synthesis new organiccomponents• Describe the basic steps in glycolysis, the TCAcycle, and the electron transport chain• Summarize the energy yield of glycolysis andcellular respiration• Describe the pathways involved in lipid, proteinand nucleic acid metabolism
  3. 3. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsLearning Objectives• Summarize the characteristics of the absorptiveand postabsorptive metabolic states• Explain what constitutes a balanced diet and whysuch a diet is important• Define metabolic rate and discuss the factorsinvolved in determining an individual’s BMR
  4. 4. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsSECTION 25-1An Overview of Metabolism
  5. 5. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Metabolism is all the chemical reactions thatoccur in an organism• Cellular metabolism• Cells break down excess carbohydrates first,then lipids• Cells conserve amino acids• 40% of the energy released in catabolism iscaptured in ATP• Rest is released as heatMetabolism
  6. 6. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.1Figure 25.1 An Introduction to CellularMetabolism
  7. 7. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Performance of structural maintenance andrepairs• Support of growth• Production of secretions• Building of nutrient reservesAnabolism
  8. 8. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.2Figure 25.2 Metabolic Turnover and CellularATP Production
  9. 9. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• cells provide small organic molecules for theirmitochondria• Mitochondria produce ATP used to performcellular functionsCells and Mitochondria
  10. 10. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.3 Nutrient Use in Cellular MetabolismFigure 25.3
  11. 11. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsSECTION 25-2Carbohydrate Metabolism
  12. 12. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Glycolysis• One molecule of glucose = two pyruvate ions,two ATP, two NADH• Aerobic metabolism (cellular respiration)• Two pyruvates = 34 ATP• The chemical formula for this process isC6H12O6 + 6 O2 → 6 CO2 + 6 H2OMost cells generate ATP through the breakdownof carbohydrates
  13. 13. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• The breakdown of glucose to pyruvic acid• This process requires:• Glucose molecules• Cytoplasmic enzymes• ATP and ADP• Inorganic phosphate• NAD (nicotinamide adenine dinucleotide)• The overall reaction is:Glucose + 2 NAD + 2 ADP + 2Pi →2 Pyruvic acid + 2 NADH + 2 ATPGlycolysis
  14. 14. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.4 GlycolysisAnimation: Steps in GlycolysisPLAYFigure 25.4
  15. 15. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.4 GlycolysisFigure 25.4
  16. 16. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Pyruvic acid molecules enter mitochondria• Broken down completely in TCA cycle• Decarboxylation• Hydrogen atoms passed to coenzymes• Oxidative phosphorylationMitochondrial ATP Production(cellular respiration)
  17. 17. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.5 The TCA CycleAnimation: TCA CyclePLAYFigure 25.5
  18. 18. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.5 The TCA CycleFigure 25.5a
  19. 19. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.5 The TCA CycleFigure 25.5b
  20. 20. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Requires coenzymes and consumes oxygen• Key reactions take place in the electron transportsystem (ETS)• Cytochromes of the ETS pass electrons tooxygen, forming water• The basic chemical reaction is:2 H2 + O2 → 2 H2OOxidative phosphorylation and the ETS
  21. 21. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.6 Oxidative PhosphorylationFigure 25.6Animation: ChemiosmosisPLAY
  22. 22. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.6 Oxidative PhosphorylationFigure 25.6a
  23. 23. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.6 Oxidative PhosphorylationFigure 25.6b
  24. 24. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Per molecule of glucose entering these pathways• Glycolysis – has a net yield of 2 ATP• Electron transport system – yieldsapproximately 28 molecules of ATP• TCA cycle – yields 2 molecules of ATPEnergy yield of glycolysis and cellularrespiration
  25. 25. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.7Figure 25.7 A Summary of the Energy Yield ofAerobic Metabolism
  26. 26. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Gluconeogenesis• Synthesis of glucose from noncarbohydrateprecursors• Lactic acid, glycerol, amino acids• Liver cells synthesis glucose whencarbohydrates are depleted• Glycogenesis• Formation of glycogen• Glucose stored in liver and skeletalmuscle as glycogen• Important energy reserveSynthesis of glucose and glycogen
  27. 27. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.8Figure 25.8 Carbohydrate Breakdown andSynthesis
  28. 28. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFundamentals ofAnatomy & PhysiologySIXTH EDITIONFredericH.MartiniChapter 25, part 2Metabolism and Energetics
  29. 29. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsSECTION 25-3Lipid Metabolism
  30. 30. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Lipolysis• Lipids broken down into pieces that can beconverted into pyruvate• Triglycerides are split into glycerol and fattyacids• Glycerol enters glycolytic pathways• Fatty acids enter the mitochondrionLipid catabolism
  31. 31. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Beta-oxidation• Breakdown of fatty acid molecules into2-carbon fragments• Enter the TCA• Irreversible• Lipids and energy production• Cannot provide large amounts in ATP in ashort amount of time• Used when glucose reserves are limitedLipid catabolism
  32. 32. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.9 Beta OxidationFigure 25.9
  33. 33. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.9 Beta OxidationFigure 25.9
  34. 34. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Almost any organic molecule can be used to formglycerol• Essential fatty acids cannot be synthesized andmust be included in diet• Linoleic and linolenic acidLipid synthesis (lipogenesis)
  35. 35. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.10 Lipid SynthesisFigure 25.10
  36. 36. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Transport assure by lipoproteins:• 5 types of lipoprotein• Lipid-protein complex that contains largeglycerides and cholesterol• Chylomicrons• Largest lipoproteins composed primarilyof triglycerides• Very low-density lipoproteins (VLDLs)• contain triglycerides, phospholipids andcholesterolLipid transport and distribution
  37. 37. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• 5 types of lipoprotein (continued)• Intermediate-density lipoproteins (IDLs)• Contain smaller amounts of triglycerides• Low-density lipoproteins (LDLs)• Contain mostly cholesterol• High-density lipoproteins (HDLs)• Equal amounts of lipid and proteinLipid transport and distribution
  38. 38. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Enzyme that breaks down complex lipids• Found in capillary walls of liver, adipose tissue,skeletal and cardiac muscle• Releases fatty acids and monglyceridesLipoprotein lipase
  39. 39. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.11 Lipid Transport and UtilizationFigure 25.11a
  40. 40. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.11 Lipid Transport and UtilizationFigure 25.11b
  41. 41. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsSECTION 25-4Protein Metabolism
  42. 42. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• If other sources inadequate, mitochondria canbreak down amino acids• TCA cycle• removal of the amino group (-NH2)• Transamination – attaches removed aminogroup to a keto acid• Deamination – removes amino groupgenerating NH4+• Proteins are an impractical source of ATPproductionAmino acid catabolism
  43. 43. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.12 Amino Acid CatabolismFigure 25.12
  44. 44. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.12 Amino Acid CatabolismFigure 25.12a
  45. 45. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.12 Amino Acid CatabolismFigure 25.12b
  46. 46. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.12 Amino Acid CatabolismFigure 25.12c
  47. 47. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Essential amino acids• Cannot be synthesized by the body in adequatesupply• Nonessential amino acids• Can be synthesized by the body via amination• Addition of the amino group to a carbonframeworkProtein synthesis
  48. 48. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.13 AminationFigure 25.13
  49. 49. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.14Figure 25.14 A Summary of the Pathways ofCatabolism and Anabolism
  50. 50. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsSECTION 25-5Nucleic Acid Metabolism
  51. 51. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Nuclear DNA is never catabolized for energy• RNA catabolism• RNA molecules are routinely broken down andreplaced• Generally recycled as nucleic acids• Can be catabolized to simple sugars andnitrogenous bases• Do not contribute significantly to energyreservesNucleic acid metabolism
  52. 52. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Most cells synthesis RNA• DNA synthesized only when preparing fordivisionNucleic acid synthesis
  53. 53. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFundamentals ofAnatomy & PhysiologySIXTH EDITIONFredericH.MartiniChapter 25, part 3Metabolism and Energetics
  54. 54. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsSECTION 25-6Metabolic Interactions
  55. 55. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• No one cell of the human body can perform allnecessary homeostatic functions• Metabolic activities must be coordinatedHomeostasis
  56. 56. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Liver• The focal point for metabolic regulation andcontrol• Adipose tissue• Stores lipids primarily as triglycerides• Skeletal muscle• Substantial glycogen reservesBody has five metabolic components
  57. 57. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Neural tissue• Must be supplied with a reliable supply ofglucose• Other peripheral tissues• Able to metabolize substrates under endocrinecontrolBody has five metabolic components
  58. 58. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• The period following a meal• Nutrients enter the blood as intestinalabsorption proceeds• Liver closely regulates glucose content of blood• Lipemia commonly marks the absorptive state• Adipocytes remove fatty acids and glycerolfrom bloodstream• Glucose molecule are catabolized and aminoacids are used to build proteinsThe absorptive state
  59. 59. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.15 The Absorptive StateFigure 25.15
  60. 60. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• From the end of the absorptive state to the nextmeal• Body relies on reserves for energy• Liver cells break down glycogen, releasingglucose into blood• Liver cells synthesize glucose• Lipolysis increases and fatty acids releasedinto blood stream• Fatty acids undergo beta oxidation and enterTCAThe Postabsorptive state
  61. 61. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Amino acids either converted to pyruvate oracetyl-CoA• Skeletal muscles metabolize ketone bodies andfatty acids• Skeletal muscle glycogen reserves brokendown to lactic acid• Neural tissue continues to be supplied withglucoseThe Postabsorptive state
  62. 62. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.16 Metabolic ReservesFigure 25.16a
  63. 63. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.17 The Postabsorptive StateFigure 25.17
  64. 64. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsSECTION 25-7Diet and Nutrition
  65. 65. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Nutrition• Absorption of nutrients from food• Balanced diet• Contains all the ingredients necessary tomaintain homeostasis• Prevents malnutritionDiet and Nutrition
  66. 66. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Food groups and food pyramids• Used as guides to avoid malnutritionFood
  67. 67. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Six basic food groups of a balance diet arrangedin a food pyramid• Milk, yogurt and cheese• Meat, poultry, fish, dry beans, eggs, and nuts• Vegetables• Fruits• Bread, cereal, rice and pasta• Base of pyramid• Fats, oils and sweets• Top of pyramidFood Groups
  68. 68. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 25.18Figure 25.18 The Food Pyramid and DietaryRecommendations
  69. 69. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• N compounds contain nitrogen• Amino acids, purines, pyrimidines, creatine,porphyrins• Body does not maintain large nitrogen reserves• Dietary nitrogen is essential• Nitrogen balance is an equalization of absorbedand excreted nitrogenNitrogen balance
  70. 70. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Act as co-factors in enzymatic reactions• Contribute to osmotic concentrations of bodyfluids• Play a role in transmembrane potentials, actionpotentials• Aid in release of neurotransmitters and musclecontraction• Assist in skeletal construction and maintenance• Important in gas transport and buffer systems• Aid in fluid absorption and waste removalMinerals
  71. 71. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Are needed in very small amounts for a variety ofvital body activities• Fat soluble• Vitamins A, D, E, K• Taken in excess can lead to hypervitaminosis• Water soluble• Not stored in the body• Lack of adequate dietary intake = avitaminosisVitamins
  72. 72. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsSECTION 25-8Bioenergetics
  73. 73. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• The study of acquisition and use of energy byorganisms• Energy content of food expressed in Caloriesper gram (C/g)Bioenergetics
  74. 74. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Catabolism of lipids yields 9.46 C/g• Catabolism of proteins and carbohydrates yields~4.7 C/gFood and energy
  75. 75. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Total of all anabolic and catabolic processesunderway• Basal metabolic rate (BMR) is the rate of energyused by a person at restMetabolic rate
  76. 76. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Homeostatic regulation of body temperature• Heat exchange with the environment involvesfour processes:• Radiation• Conduction• Convection• EvaporationThermoregulation
  77. 77. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.19 Routes of Heat Gain and LossFigure 25.19
  78. 78. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Preoptic area of hypothalamus acts as thermostat• Heat-loss center• Heat-gain center• Mechanisms for increasing heat loss include:• Peripheral vasodilation• Increase perspiration• Increase respiration• Behavioral modificationsRegulation of heat gain and loss
  79. 79. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Decreased blood flow to the dermis• Countercurrent heat exchange• Shivering thermogenesis and nonshiveringthermogenesis• Differs by individuals due to acclimatizationMechanisms promoting heat gain
  80. 80. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin CummingsFigure 25.20 Countercurrent Heat ExchangeFigure 25.20
  81. 81. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Problems in infants• Lose heat quickly due to their small size• Do not shiver• Use brown fat to accelerate lipolysis - energyescapes as heat• Variations in adults• Use subcutaneous fat as an insulator• Different hypothalamic thermostatic settingsThermoregulation
  82. 82. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Fever is body temperature greater than 37.2oC• Can result from a variety of situations including:• Heat exhaustion or heat stroke• Congestive heart failure• Impaired sweat gland activity• Resetting of the hypothalamic thermostat bycirculating pyrogensPyrexia is elevated body temperature
  83. 83. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• Why cells need to synthesis new organiccomponents• The basic steps in glycolysis, the TCA cycle, andthe electron transport chain• The energy yield of glycolysis and cellularrespiration• The pathways involved in lipid, protein andnucleic acid metabolismBMRYou should now be familiar with:
  84. 84. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings• The characteristics of the absorptive andpostabsorptive metabolic states• What constitutes a balanced diet and why such adiet is important• Metabolic rate and the factors involved indetermining an individual’s BMRYou should now be familiar with:

×