Human Physiology Cell Metabolism

  1. Which is the major contributor to ATP synthesis...substrate-level phosphorylation...or...oxydative phosphorylation?
    Oxydative phosphorylation.

    (requires ETC and O2)
  2. Nicotinamide adenine dinucleotide (NAD+) is derived from what?

    What is this derivative made from?
    Niacin (aka nicotinic acid or vitamin B3)

    Niacin can be made from the a.a. tryptophan

    Niacin deficiency is called Pellagra
  3. Flavine adenine dinucleotide (FAD) is derived from what?

    Where is this derivative found?
    Riboflavin (aka vitamin B2 or vitamin G)

    Cannot be stored by body and is found in green veg, dairy, liver, yeast, nuts

    B2 deficiency called Ariboflavinosis
  4. Where does glycolysis occur?

    What are the products of glycolysis?
    Occurs in they cytoplasm.

    1 Glucose-->38 ATP
  5. Where does the Krebs cycle occur (aka citric acid cycle)?

    What are the products of Krebs?
    Occurs in the mitochondria

    2 pyruvate-->8 NADH + 2 FADH2 +2 ATP
  6. Where does lypolysis occur?

    What are the products of lypolysis?
    Occurs in the inner membrane of mitochondria

    • glycerol--->20 ATP
    • 2-C block--->17 ATP

    "20-17 Rule"
  7. What does hexokinase1,2,3 do?
    It phosphorylates 6C-glucose into G-6-P using a P from ATP

    c-c-c-c-c-c ---> c-c-c-c-c-c-P

    G-6 can leave cell, G-6-P can not
  8. What does phosphoglucoisomerase do?
    Converts G-6-P into F-6-P and vise versa.

    G-6-P <===> F-6-P
  9. What molecule inhibits hexokinase1,2,3?

    (example of negative feedback)
  10. What does phosphofructokinase do?
    Phosphorylates F-6-P into F-1,6-DP using a P from ATP

    c-c-c-c-c-c-P ---> P-c-c-c-c-c-c-P
  11. What inhibits phosphofructokinase?
    Mainly ATP but citrate increases ATP's ability to inhibit it
  12. What reverses ATP's inhibition of phosphofructokinase?
    • AMP,
    • thus phosphofructokinase is tightly controlled by the ratio of AMP/ATP
  13. F-1,6-DP is broken into what during glycolysis?
    Glyceraldehyde 3-Phosphate (G3P)

    F-1,6-DP ----> G3P + G3P

    P-c-c-c-c-c-c-P ---> P-c-c-c + c-c-c-P
  14. Pyruvate moves __________ from glycolysis into the mitochondria via a carrier protein and through the Krebs cycle.
  15. What is the product for every 1 Acetyl CoA that enters the Krebs cycle?
    1 Acetly CoA=Krebs=>

    • 1ATP
    • 1FAHD
    • 2NADH
  16. NADH = ? ATP

    FADH = ? ATP
    NADH ==> 3 ATP

    FADH ==> 2 ATP
  17. 1 molecule of glucose = ? ATP
    1 molcecule of glucose ==> 38 ATP

    • 2 ATP from glycolysis
    • 2 ATP from Krebs
    • 34 ATP from ETC
  18. What does lipase do?
    Brakes the bonds between the carbon backbone and the fatty acid tails in glycerides.

    Glyceride = free fatty acids + glycerol
  19. Where does glycerol breakdown occur?
    Liver or kidneys.

    glycerol 3-phosphate --> dihydroxyacetone --> glyceraldehyde 3-phosphate
  20. Explain lipolysis in the mitochondria...
    beta-oxydation breaks down fatty acids 2 carbons at a time

    2-C block => 17 ATP
  21. Define proteolysis...
    Protein breakdown during starvation

    • Proteins(muscles)-->A.A.'s-->Pyruvate
    • -->glyceraldehyde 3-phosphate-->
    • Glucose

    This is an example of gluconeogenesis
  22. What are the most important amino acids for energy production?
    glutamine and alanine
  23. What is another name for hexokinase-4 and what makes it different from other hexokinase?
    Glucokinase (aka hexokinase-4) only works when glucose concentrations are 100x higher than hexokinase1,2,3 and glucokinase is not inhibited by G-6-P like hexokinase1,2,3
  24. What does glycogen synthase do?
    It links G-6-P molecules together to form glycogen.
  25. What does glycogen phosphorylase do?
    Converts glycogen back into G-6-P
  26. What does glucose-6-phosphatase do?
    Converts G-6-P into glucose

    (*muscle lacks glucose-6-phosphatase so G-6-P is trapped there and can't be used by other organs)
  27. Where is glycogen that is accessible to most organs, including the brain, stored?
    In the liver
  28. What is special about glycogen found in muscles?
    Glycogen here is available only to muscles and is found at much lower concentrations than in the liver, but the total amount exceeds that in the liver.
  29. Insulin promotes ____________

    Insulin inhibits _____________
    Insulin promotes glycogen synthase (energy storage).

    Insulin inhibits glycogen phosphorylase (releasing energy).
  30. Glucagon promotes ______________

    Glucagon inhibits ________________
    Glucagon promotes glycogen phosphorylase (releasing energy).

    Glucagon inhibits glycogen synthase (energy storage).
  31. As blood glucose levels rise, the pancreas secretes insulin. What does insulin do and what are the consequences of insulin overdose?
    Insulin acts on hepatic cells to stimulate the action of glycogen synthase.

    Insulin overdose drives glucose out of the blood, thus starving the brain.
  32. Glycogenolysis is the process of glycogen degradation to release glucose. What is the primary enzyme of glycogen breakdown?
    Glycogen phosphorylase
  33. Explain the effects of glucagon (from the pancreas) and epinephrine (from the adrenal medullary) regarding glycogen.
    Both glucagon and epinephrine serve to inhibit glycogen synthase (soring energy) and activate glycogen phosphorylase (releasing energy).

    *Sympathetic response
  34. What ions are commonly found at higher concentrations outside the cell (ECF)?
    Na+ , Cl- , Ca2+
  35. What molecules are commonly found within the cell (ICF) and what are their charges?
    K+ , proteins- , cAMP- , ATP- , PKA-
  36. Why does the cell attract cations?
    The cell has a negative net charge that attracts positive ions.
  37. Where does the energy come from that links inorganic-P onto ADP?
    The potential energy from the difference in concentrations of protons between the inner and outer membranes of the mitochondria
  38. What does glycogen synthase do?
    Adds glucose molecules to chains of glycogen as a way to store energy
  39. What does glycogen phosphorylase do?
    Breaks off glucose molecules from glycogen chains as a way to free energy that has been stored
  40. Muscle lacks ___________________ so G-6-P can not leave the cell and can only be used by the muscle
    Muscle lacks glucose-6-phosphatase so G-6-P can not leave the cell and can only be used by the muscle
Card Set
Human Physiology Cell Metabolism
Flashcards for Human Phys exam 1