Chapter7
- 2. IntroductionIntroduction • Energy • Heat, mechanical, electrical, chemical • Photosynthesis • Metabolism • Release of energy, water, and carbon dioxide
- 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. A Typical CellA Typical Cell
- 5. Anabolic and CatabolicAnabolic and Catabolic Reactions ComparedReactions Compared
- 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. Capture and Release of EnergyCapture and Release of Energy by ATPby ATP
- 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. 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. 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. Simplified Overview of Energy-Simplified Overview of Energy- Yielding PathwaysYielding Pathways
- 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)
- 14. 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
- 15. 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
- 17. 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
- 19. The Paths of Pyruvate andThe Paths of Pyruvate and Acetyl CoAAcetyl CoA
- 20. Glucose Enters the EnergyGlucose Enters the Energy PathwayPathway
- 21. 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
- 22. Fatty Acids-to-Acetyl CoAFatty Acids-to-Acetyl CoA
- 23. Fats Enter the Energy PathwayFats Enter the Energy Pathway
- 24. 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
- 25. Review of Energy-Yielding Nutrient Endpoints
- 26. 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
- 28. 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
- 29. Final Steps of Energy Metabolism • kCalorie-per-gram secret • Fat provides most energy per gram • Carbon-hydrogen bonds • More ATP = more kcalories
- 31. 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
- 32. 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
- 33. Feasting and FastingFeasting and Fasting
- 34. 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
- 35. 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
- 36. Ketone Body FormationKetone Body Formation
- 37. 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
- 38. 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
- 39. Adverse Side Effects of Low- Carbohydrate, Ketogenic Diets
- 40. Alcohol in theAlcohol in the BodyBody Highlight 7Highlight 7
- 41. Alcohol in the BodyAlcohol in the Body • Potential health benefits • Alcohols • Glycerol • Ethanol • Lipid solvents • Moderation • Definition of “drink” • Proof
- 42. AlcoholAlcohol’s Influence’s Influence • Alcohol’s special privileges • No digestion • Quick absorption • Slowing absorption • Stomach • Alcohol dehydrogenase • Small intestine • Priority over nutrients
- 43. 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
- 45. 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
- 46. Alternate Route for AcetylAlternate Route for Acetyl CoA: To FatCoA: To Fat
- 47. AlcoholAlcohol’s Influence’s Influence • In the liver • Immune system functioning • Alcohol interferes with drug metabolism • Microsomal ethanol-oxidizing system (MEOS)
- 48. 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
- 49. AlcoholAlcohol’s Effects on the Brain’s Effects on the Brain
- 50. Alcohol Doses & Approximate Blood Level Percentages for Men & Women
- 51. Alcohol Blood Levels andAlcohol Blood Levels and Brain ResponsesBrain Responses
- 52. AlcoholAlcohol’s Damage’s Damage • Dehydration • Antidiuretic hormone (ADH) • Water loss • Loss of minerals
- 53. 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
- 54. 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