Biochem Glycolysis

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Biochem Glycolysis
2011-02-07 21:44:14
Biochem Glycolysis

Biochem Glycolysis
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  1. What are the 3 irriversible steps in glycolysis?
    • Hexokinase
    • Phosphofructose kinase 1 (PFK-1)
    • Pyruvate Kinase
  2. What is the Enzyme that is rate determining in Gycolysis?
    Phosphofructokinase (PFK-1)
  3. What is the committing step in glycolysis?
    • Formation of 1,6-bisphosphate bc it is committed to Glycolysis
    • The previous steps could have gone to other pathways like HMP shunt or glycogen synthesis
  4. Phosphorylation of glucose to G-6-Phosphate is done by what enzymes in the muscle, brain and liver?
    Beta-cells, Liver?
    • Muscle, brain, Liver--Hexokinase
    • Beta-cells, liver--glucokinase
  5. Whats the negative feedback inhibition for Hexokinase?
    • Hexokinase--G-6-phosphate
    • Glucokinase--no inhibitor
  6. What are the only ketogenic A.A..capable of forming ketone bodies to be used as energy by the brain?
    Lysine and Leucine
  7. High levels of Fructose 1,6 - bisphosphate stimulate what enzyme in the Glycolytic Pathway?
    Pyruvate kinase
  8. What inhibits pyruvate kinase enzyme glycolysis?
    phosphorylation by protein kinase A which is activated by cAMP which is in turn activated by glucagon
  9. What inhibits Hexokinase?
    Glucose 6 phosphate
  10. What inhibits Glucokinase
    Fructose 6 phosphate
  11. Whats an allosteric activator of PFK-1?
    Fructose 2,6 Bisphosphate
  12. PFK-2 kinase activity is active when it is phosphorylated or dephosphorylated?
  13. PFK-2 phosphatase activity is active when phospho or dephosphorylated?
  14. Phosphorylation of glycolytic enzymes leads to their activation or inactivation?
  15. Whats the consequence of converting 1,3 bisphosphoglycerate to 2,3 bisphosphoglycerate?
    Loss of an ATP
  16. Arsenic blocks what glycolytic enzyme?
    Glyceraldehyde-3 phosphate dehydrogenase
  17. Flouride blocks what glycolytic enzyme?
  18. Whats the function of enolase?
    converts phosphoenolpyruvate to pyruvate
  19. What enzyme is similar to alpha ketoglutarate dehydrogenase?
    Pyruvate dehydrogenase Complex
  20. What are the cofactors needed for alpha ketoglutarate dehydrogenase?
    • 1.thiamine
    • 2. lipoic acid
    • 3.Mg
    • 4.NAD
    • 5. FAD
    • 6. coA
  21. ionic calcium in TCA cycle stimulates what enzymes?
    Isocitrate dehydrogenase and apha ketoglutarate dehydrogenase
  22. Whats the product of hydrogenating alpha ketoglutarate?
  23. Arsenic blocks what in glycolysis?
    • Glyceraldehyde 3 phosphate dehydrogenase
    • In PDC binds Lipoic Acid
  24. Flouroacetate (RAT poison) blocks what?
    Aconitase which converts citrate to isocitrate
  25. Arsenic blocks what enzymes?
    • In glycolysis--glyceraldehyde 3 phosphate dehydrogenase
    • In TCA-- alpha KG dehydrogenase and succinic dehydrogenase
    • In PDC--lipoic acid