A&P Chapter 25 - Metabolism

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A&P Chapter 25 - Metabolism
2011-02-03 15:37:02
Chapter Metabolism

A&P Chapter 25 - Metabolism
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  1. metabolism
    • every chemical reaction works to generate ATP
    • major reactions are oxidation/reduction reactions
    • stored energy is released/transferred to other substances
  2. oxidation
    • electrons or hydrogen ions removed from a molecule
    • gives up energy
    • generate ATP
    • almost all ATP comes from oxidation of food
  3. reduction
    • electrons or hydrogen ions are added to a molecule
    • gain energy
  4. glycogenesis
    • production of glycogen from glucose
    • anabolic
    • glycogen is stored
  5. glycogenolysis
    stored glycogen converted back to glucose
  6. gluconeogenesis
    • glucose forms from non-carbs (usually fat)
    • occurs when no glucose is available and all glycogen is used up
  7. carbohydrate metabolism
    • poly/disacharrides -> monosaccharides -> glucose
    • gluose enters cell through facilitated diffusion with the help of insulin
    • energy needed: glucose oxidized to make ATP
    • energy not needed: glucose converted to glycogen and store in liver/skeletal muscle until needed
    • glucose releases 36-38 ATP released
    • 3 steps: glycolosis, krebs cycle, electron transport chain
  8. glycolysis
    • occur in the cytoplasm outside of the mitochondria
    • glucose is split into 2 molecules of pyruvic acid
    • can occur aerobically or anaerobically
    • controlled by enzymes
    • steps 1-3:
    • --cell invests 2 ATP
    • --glucose (C6-H12-O6) enters cell (facilitated diffusion w/ insulin)
    • --glucose is phosphorylated
    • --glucose becomes fructose
    • --fructose is phosphorylated
    • steps 4-5:
    • --fructose splits into G3P and DHP
    • step 6:
    • --G3P and DHP oxidized
    • steps 7-10:
    • --2 PA (C3) molecules produced
    • --4 ATP released (net 2 gained by cell), 32-34 remain
  9. phosphorylated
    a phosphate group attaches to glucose to make it bigger so it cannot slide out of cell
  10. phosphofructokinase
    • enzyme that catalyzes step 3 of glycolysis
    • controls the speed of glycolysis
  11. lactic acid
    • if no O2 present, PA becomes lactic acid
    • will stay in the cell until O2 is present or will go to the liver to convert back to PA
  12. acetyl coenzyme A formation
    • PA must be converted before entering the Krebs Cycle
    • no ATP generated
    • steps:
    • --PA (C3) is decarboxylized, CO2 is removed
    • --C2 acetyl group is formed
    • --coenzyme A is added
    • --acetyl coenzyme A (C2) is formed
    • --32-34 ATP remain
  13. krebs cycle
    • series of oxidation/reduction reactions
    • occurs in the outer membrane of the mitochondria
    • steps:
    • --acetyl coenzyme A (C2) + oxaloacetic acid (C4) -> citric acid (C6)
    • --citric acid is oxidized
    • --end result - 4C02, 2 GTP (ATP), 6 NADH + H+, 2 FADH
    • --6 NADH + H+ and 2 FADH are reduced coenzymes, 30-32 ATP remain
  14. electron transport chain
    • series of reactions where reduced coenzymes release all ATP into the cell
    • occurs in inner membrane of mitochondria
    • involes electron carrier molecules
    • coenzymes release ATP at each turn
    • H20 forms at the end
  15. lipid metabolism
    • triglycerides -> fatty acid + glycerol
    • glycerol -> G3P -> moves through glycolysis
    • fatty acid -> beta oxidations -> acetyl coenzyme A -> enters Krebs Cycle
  16. ketogenesis
    • ketone bodies are formed in the liver from excess acetyl coenzyme A
    • condition is called ketosis
    • liver eventually converts ketone bodies back into ACOA
  17. lipogenesis
    extra glucose converted to fat
  18. protein metabolism
    • protein -> amino acids
    • protein should be the last source for energy
    • amino acids must be deaminated
    • amino group -> liver -> NH3 (ammonia) -> NH4 (ammonium) -> urea -> pee
    • remaining amino acid will enter pre-Krebs
  19. essential amino acids
    • 10 amino acids that the body does not produce
    • must come from the diet
  20. non-essential amino acids
    10 amino acids produced by the body
  21. transamination
    the process by with the body produces amino acids
  22. metabolic rate
    production of heat or energy from food
  23. basal metabolic rate
    • measurement of how fast the body breaks down food and generates ATP
    • depends on age, surface area, and gender
  24. homeotherms
    • humans maintain a constanst body temp within a range
    • temp is lowest in the AM
    • heat produced = heat lost
  25. fever
    produce more heat than is lost
  26. hypothermia
    lose more heat than is produced
  27. heat production
    • skeletal muscle contraction: generates most heat
    • T4 (thyroxine): increase MR which increases body temp
    • SNS stimulation: in emergency, body temp increases
    • vasoconstriction: shivering, goose bumps send blood to inside of body
  28. heat loss
    • radiation: body heat transferred to cooler substances NOT in direct contact
    • conduction: body heat transferred to cooler substance in direct contact
    • convection: body heat transferred to a gas that is a lower temp
    • evaporation: body heat transferred to a liquid then a vapor