EnergyEnergy
MetabolismMetabolism
Chapter 7Chapter 7
IntroductionIntroduction
• Energy
• Heat, mechanical, electrical, chemical
• Photosynthesis
• Metabolism
• Release of ener...
Chemical Reactions in theChemical Reactions in the
BodyBody
• Energy metabolism
• How body obtains & uses energy from food...
A Typical CellA Typical Cell
Anabolic and CatabolicAnabolic and Catabolic
Reactions ComparedReactions Compared
Chemical Reactions in theChemical Reactions in the
BodyBody
• Transfer of energy in reactions – ATP
• Released during brea...
Capture and Release of EnergyCapture and Release of Energy
by ATPby ATP
Chemical Reactions in theChemical Reactions in the
BodyBody
• Enzymes
• Facilitators of metabolic reactions
• Coenzymes
• ...
Breaking Down Nutrients forBreaking Down Nutrients for
EnergyEnergy
• Digestion
• Carbohydrates – glucose (& other
monosac...
Breaking Down Nutrients forBreaking Down Nutrients for
EnergyEnergy
• Two new compounds
• Pyruvate
• 3-carbon structure
• ...
Simplified Overview of Energy-Simplified Overview of Energy-
Yielding PathwaysYielding Pathways
Breaking Down Nutrients forBreaking Down Nutrients for
Energy – GlucoseEnergy – Glucose
• Glucose-to-pyruvate
• Glycolysis...
Breaking Down Nutrients forBreaking Down Nutrients for
Energy – GlucoseEnergy – Glucose
• Pyruvate’s options
• Quick energ...
Breaking Down Nutrients forBreaking Down Nutrients for
Energy – GlucoseEnergy – Glucose
• Pyruvate-to-lactate
• Pyruvate a...
Pyruvate-to-LactatePyruvate-to-Lactate
Breaking Down Nutrients forBreaking Down Nutrients for
Energy – GlucoseEnergy – Glucose
• Pyruvate-to-Acetyl CoA
• Pyruvat...
Pyruvate-Acetyl CoAPyruvate-Acetyl CoA
The Paths of Pyruvate andThe Paths of Pyruvate and
Acetyl CoAAcetyl CoA
Glucose Enters the EnergyGlucose Enters the Energy
PathwayPathway
Breaking Down Nutrients forBreaking Down Nutrients for
Energy – Glycerol & Fatty AcidsEnergy – Glycerol & Fatty Acids
• Gl...
Fatty Acids-to-Acetyl CoAFatty Acids-to-Acetyl CoA
Fats Enter the Energy PathwayFats Enter the Energy Pathway
Breaking Down Nutrients forBreaking Down Nutrients for
Energy – Amino AcidsEnergy – Amino Acids
• Deamination of amino aci...
Review of Energy-Yielding
Nutrient Endpoints
Final Steps of EnergyFinal Steps of Energy
MetabolismMetabolism
• TCA Cycle
• Inner compartment of mitochondria
• Circular...
Final Steps of EnergyFinal Steps of Energy
MetabolismMetabolism
• Electron transport chain
• Captures energy in ATP
• Seri...
Final Steps of Energy
Metabolism
• kCalorie-per-gram secret
• Fat provides most energy per gram
• Carbon-hydrogen bonds
• ...
Feasting – Excess EnergyFeasting – Excess Energy
• Metabolism favors fat formation
• Regardless of excess from protein, fa...
Transition from Feasting toTransition from Feasting to
FastingFasting
• Glucose, glycerol, and fatty acids are used
then s...
Feasting and FastingFeasting and Fasting
Fasting – Inadequate EnergyFasting – Inadequate Energy
• Carbohydrate, fat, and protein are all
eventually used for energy...
Fasting – Inadequate EnergyFasting – Inadequate Energy
• Adaptation: making glucose
• Nervous system and red blood cells
•...
Ketone Body FormationKetone Body Formation
Energy Balance – FastingEnergy Balance – Fasting
• Adaptation: conserving energy
• Hormones
• Reduces energy output
• Supp...
Low-Carbohydrate DietsLow-Carbohydrate Diets
• Metabolism similar to fasting
• Uses glycogen stores first
• Gluconeogenesi...
Adverse Side Effects of Low-
Carbohydrate, Ketogenic Diets
Alcohol in theAlcohol in the
BodyBody
Highlight 7Highlight 7
Alcohol in the BodyAlcohol in the Body
• Potential health
benefits
• Alcohols
• Glycerol
• Ethanol
• Lipid solvents
• Mode...
AlcoholAlcohol’s Influence’s Influence
• Alcohol’s special privileges
• No digestion
• Quick absorption
• Slowing absorpti...
AlcoholAlcohol’s Influence’s Influence
• In the liver
• Liver cells
• First to receive alcohol-laden blood
• Alcohol dehyd...
Alcohol MetabolismAlcohol Metabolism
AlcoholAlcohol’s Influence’s Influence
• In the liver
• Niacin coenzyme
• Glycolysis
• TCA cycle
• Electron transport chai...
Alternate Route for AcetylAlternate Route for Acetyl
CoA: To FatCoA: To Fat
AlcoholAlcohol’s Influence’s Influence
• In the liver
• Immune system functioning
• Alcohol interferes with drug metabolis...
AlcoholAlcohol’s Influence’s Influence
• In the brain
• Sedates inhibitory nerves
• Acts as central nervous system depress...
AlcoholAlcohol’s Effects on the Brain’s Effects on the Brain
Alcohol Doses & Approximate Blood
Level Percentages for Men & Women
Alcohol Blood Levels andAlcohol Blood Levels and
Brain ResponsesBrain Responses
AlcoholAlcohol’s Damage’s Damage
• Dehydration
• Antidiuretic hormone (ADH)
• Water loss
• Loss of minerals
Alcohol’s Damage
• Malnutrition
• Can contribute to body fat and weight gain
• 1 ounce of alcohol represents 0.5 ounce of ...
AlcoholAlcohol’s Effects’s Effects
• Short-term effects
• Excessive drinking
• Heavy drinking
• Binge drinking
• Long-term...
Signs of Alcoholism
Chapter7
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Chapter7

  1. 1. EnergyEnergy MetabolismMetabolism Chapter 7Chapter 7
  2. 2. IntroductionIntroduction • Energy • Heat, mechanical, electrical, chemical • Photosynthesis • Metabolism • Release of energy, water, and carbon dioxide
  3. 3. Chemical Reactions in theChemical Reactions in the BodyBody • Energy metabolism • How body obtains & uses energy from food • Cells • Liver cells • Anabolism • Requires energy • Catabolism • Releases energy
  4. 4. A Typical CellA Typical Cell
  5. 5. Anabolic and CatabolicAnabolic and Catabolic Reactions ComparedReactions Compared
  6. 6. Chemical Reactions in theChemical Reactions in the BodyBody • Transfer of energy in reactions – ATP • Released during breakdown of glucose, fatty acids, and amino acids • Form of phosphate groups • Negative charge – vulnerable to hydrolysis • Provides energy for all cell activities • Coupled reactions • Efficiency • Heat loss
  7. 7. Capture and Release of EnergyCapture and Release of Energy by ATPby ATP
  8. 8. Chemical Reactions in theChemical Reactions in the BodyBody • Enzymes • Facilitators of metabolic reactions • Coenzymes • Organic • Associate with enzymes • Without coenzyme, an enzyme cannot function
  9. 9. Breaking Down Nutrients forBreaking Down Nutrients for EnergyEnergy • Digestion • Carbohydrates – glucose (& other monosaccharides) • Fats (triglycerides) – glycerol and fatty acids • Proteins – amino acids • Molecules of glucose, glycerol, amino acids, and fatty acids • Catabolism • Carbon, nitrogen, oxygen, hydrogen
  10. 10. Breaking Down Nutrients forBreaking Down Nutrients for EnergyEnergy • Two new compounds • Pyruvate • 3-carbon structure • Can be used to make glucose • Acetyl CoA • 2-carbon structure • Cannot be used to make glucose • TCA cycle and electron transport chain
  11. 11. Simplified Overview of Energy-Simplified Overview of Energy- Yielding PathwaysYielding Pathways
  12. 12. Breaking Down Nutrients forBreaking Down Nutrients for Energy – GlucoseEnergy – Glucose • Glucose-to-pyruvate • Glycolysis • 2 pyruvate molecules • Hydrogen atoms carried to electron transport chain • Pyruvate can be converted back to glucose • Liver cells and kidneys (to some extent)
  13. 13. Breaking Down Nutrients forBreaking Down Nutrients for Energy – GlucoseEnergy – Glucose • Pyruvate’s options • Quick energy needs – anaerobic • Pyruvate to lactate • Slower energy needs – aerobic • Pyruvate to acetyl CoA
  14. 14. Breaking Down Nutrients forBreaking Down Nutrients for Energy – GlucoseEnergy – Glucose • Pyruvate-to-lactate • Pyruvate accepts hydrogens • Converts pyruvate to lactate • Occurs to a limited extent at rest • Produces ATP quickly • Mitochondrial ability • Accumulation of lactate in muscles • Effects • Cori cycle
  15. 15. Pyruvate-to-LactatePyruvate-to-Lactate
  16. 16. Breaking Down Nutrients forBreaking Down Nutrients for Energy – GlucoseEnergy – Glucose • Pyruvate-to-Acetyl CoA • Pyruvate enters mitochondria of cell • Carbon removed – becomes carbon dioxide • 2-carbon compound joins with CoA becoming acetyl CoA – irreversible • Acetyl CoA pathways
  17. 17. Pyruvate-Acetyl CoAPyruvate-Acetyl CoA
  18. 18. The Paths of Pyruvate andThe Paths of Pyruvate and Acetyl CoAAcetyl CoA
  19. 19. Glucose Enters the EnergyGlucose Enters the Energy PathwayPathway
  20. 20. Breaking Down Nutrients forBreaking Down Nutrients for Energy – Glycerol & Fatty AcidsEnergy – Glycerol & Fatty Acids • Glycerol-to-pyruvate • Glycerol can be converted • Glucose • Pyruvate • Fatty acids-to-Acetyl CoA • Fatty acid oxidation • 2-carbon units at a time then join with CoA • Hydrogens and electrons carried to electron transport chain
  21. 21. Fatty Acids-to-Acetyl CoAFatty Acids-to-Acetyl CoA
  22. 22. Fats Enter the Energy PathwayFats Enter the Energy Pathway
  23. 23. Breaking Down Nutrients forBreaking Down Nutrients for Energy – Amino AcidsEnergy – Amino Acids • Deamination of amino acids • Amino acids-to-energy • Several entry points in energy pathway • Converted to pyruvate (glucogenic) • Converted to acetyl CoA (ketogenic) • Enter TCA cycle directly (glucogenic) • Amino acids-to-glucose
  24. 24. Review of Energy-Yielding Nutrient Endpoints
  25. 25. Final Steps of EnergyFinal Steps of Energy MetabolismMetabolism • TCA Cycle • Inner compartment of mitochondria • Circular path • Acetyl CoA • Oxaloacetate – made primarily from pyruvate • Carbon dioxide release • Hydrogen atoms and their electrons • Niacin and riboflavin
  26. 26. Final Steps of EnergyFinal Steps of Energy MetabolismMetabolism • Electron transport chain • Captures energy in ATP • Series of proteins • Electron “carriers” • Inner membrane of mitochondria • Electrons passed to next carrier • Join oxygen at end of chain – water released • ATP synthesis
  27. 27. Final Steps of Energy Metabolism • kCalorie-per-gram secret • Fat provides most energy per gram • Carbon-hydrogen bonds • More ATP = more kcalories
  28. 28. Feasting – Excess EnergyFeasting – Excess Energy • Metabolism favors fat formation • Regardless of excess from protein, fat, or carbohydrates • Excess protein • Excess carbohydrate • Excess fat – most direct and efficient conversion • Fuel mix
  29. 29. Transition from Feasting toTransition from Feasting to FastingFasting • Glucose, glycerol, and fatty acids are used then stored • Fasting state draws on these stores • Glycogen and fat are released • Basal metabolism • Fasting versus starving
  30. 30. Feasting and FastingFeasting and Fasting
  31. 31. Fasting – Inadequate EnergyFasting – Inadequate Energy • Carbohydrate, fat, and protein are all eventually used for energy • Begin with release of glucose and fatty acids • Acetyl CoA • Low blood glucose levels signal • Fat breakdown • Release of amino acids from muscles
  32. 32. Fasting – Inadequate EnergyFasting – Inadequate Energy • Adaptation: making glucose • Nervous system and red blood cells • Amino acids yielding pyruvate • Breakdown of body proteins • Adaptation: creating an alternate fuel • Use fat to fuel brain • Ketone bodies • Slows the rate of body protein breakdown • Ketosis induces a loss of appetite
  33. 33. Ketone Body FormationKetone Body Formation
  34. 34. Energy Balance – FastingEnergy Balance – Fasting • Adaptation: conserving energy • Hormones • Reduces energy output • Supports weight loss but not fat loss • Symptoms of starvation • Physical symptoms • Psychological symptoms
  35. 35. Low-Carbohydrate DietsLow-Carbohydrate Diets • Metabolism similar to fasting • Uses glycogen stores first • Gluconeogenesis when glycogen is depleted • Body tissues used somewhat even when protein provided in diet • Urine monitoring • Ketosis
  36. 36. Adverse Side Effects of Low- Carbohydrate, Ketogenic Diets
  37. 37. Alcohol in theAlcohol in the BodyBody Highlight 7Highlight 7
  38. 38. Alcohol in the BodyAlcohol in the Body • Potential health benefits • Alcohols • Glycerol • Ethanol • Lipid solvents • Moderation • Definition of “drink” • Proof
  39. 39. AlcoholAlcohol’s Influence’s Influence • Alcohol’s special privileges • No digestion • Quick absorption • Slowing absorption • Stomach • Alcohol dehydrogenase • Small intestine • Priority over nutrients
  40. 40. AlcoholAlcohol’s Influence’s Influence • In the liver • Liver cells • First to receive alcohol-laden blood • Alcohol dehydrogenase • Disrupts liver activity • Can permanently change liver cell structure • Rate of alcohol metabolism • Acetaldehyde • Acetate
  41. 41. Alcohol MetabolismAlcohol Metabolism
  42. 42. AlcoholAlcohol’s Influence’s Influence • In the liver • Niacin coenzyme • Glycolysis • TCA cycle • Electron transport chain • Development of fatty liver • Damage to central nervous system • Inflammation of joints • Amino acid and protein metabolism
  43. 43. Alternate Route for AcetylAlternate Route for Acetyl CoA: To FatCoA: To Fat
  44. 44. AlcoholAlcohol’s Influence’s Influence • In the liver • Immune system functioning • Alcohol interferes with drug metabolism • Microsomal ethanol-oxidizing system (MEOS)
  45. 45. AlcoholAlcohol’s Influence’s Influence • In the brain • Sedates inhibitory nerves • Acts as central nervous system depressant • Blood alcohol levels and brain responses • Death of liver and brain cells • Depression of antidiuretic hormone (ADH) • Loss of body water • Loss of important minerals
  46. 46. AlcoholAlcohol’s Effects on the Brain’s Effects on the Brain
  47. 47. Alcohol Doses & Approximate Blood Level Percentages for Men & Women
  48. 48. Alcohol Blood Levels andAlcohol Blood Levels and Brain ResponsesBrain Responses
  49. 49. AlcoholAlcohol’s Damage’s Damage • Dehydration • Antidiuretic hormone (ADH) • Water loss • Loss of minerals
  50. 50. Alcohol’s Damage • Malnutrition • Can contribute to body fat and weight gain • 1 ounce of alcohol represents 0.5 ounce of fat • Central obesity • Substituted energy • 7 kcalories per gram • Nutrient displacement • B vitamins • Wernicke-Korsakoff syndrome
  51. 51. AlcoholAlcohol’s Effects’s Effects • Short-term effects • Excessive drinking • Heavy drinking • Binge drinking • Long-term effects • Third leading preventable cause of death in U.S. • Sobering up
  52. 52. Signs of Alcoholism

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