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What are the 3 irriversible steps in glycolysis?
- Hexokinase
- Phosphofructose kinase 1 (PFK-1)
- Pyruvate Kinase
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What is the Enzyme that is rate determining in Gycolysis?
Phosphofructokinase (PFK-1)
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What is the committing step in glycolysis?
Why?
- 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
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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
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Whats the negative feedback inhibition for Hexokinase?
Glucokinase?
- Hexokinase--G-6-phosphate
- Glucokinase--no inhibitor
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What are the only ketogenic A.A..capable of forming ketone bodies to be used as energy by the brain?
Lysine and Leucine
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High levels of Fructose 1,6 - bisphosphate stimulate what enzyme in the Glycolytic Pathway?
Pyruvate kinase
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What inhibits pyruvate kinase enzyme glycolysis?
phosphorylation by protein kinase A which is activated by cAMP which is in turn activated by glucagon
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What inhibits Hexokinase?
Glucose 6 phosphate
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What inhibits Glucokinase
Fructose 6 phosphate
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Whats an allosteric activator of PFK-1?
Fructose 2,6 Bisphosphate
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PFK-2 kinase activity is active when it is phosphorylated or dephosphorylated?
Dephosphorylated
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PFK-2 phosphatase activity is active when phospho or dephosphorylated?
phosphorylated
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Phosphorylation of glycolytic enzymes leads to their activation or inactivation?
Inactivation
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Whats the consequence of converting 1,3 bisphosphoglycerate to 2,3 bisphosphoglycerate?
Loss of an ATP
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Arsenic blocks what glycolytic enzyme?
Glyceraldehyde-3 phosphate dehydrogenase
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Flouride blocks what glycolytic enzyme?
Enolase
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Whats the function of enolase?
converts phosphoenolpyruvate to pyruvate
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What enzyme is similar to alpha ketoglutarate dehydrogenase?
Pyruvate dehydrogenase Complex
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What are the cofactors needed for alpha ketoglutarate dehydrogenase?
- 1.thiamine
- 2. lipoic acid
- 3.Mg
- 4.NAD
- 5. FAD
- 6. coA
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ionic calcium in TCA cycle stimulates what enzymes?
Isocitrate dehydrogenase and apha ketoglutarate dehydrogenase
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Whats the product of hydrogenating alpha ketoglutarate?
Glutamate
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Arsenic blocks what in glycolysis?
PDC?
- Glyceraldehyde 3 phosphate dehydrogenase
- In PDC binds Lipoic Acid
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Flouroacetate (RAT poison) blocks what?
Aconitase which converts citrate to isocitrate
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Arsenic blocks what enzymes?
- In glycolysis--glyceraldehyde 3 phosphate dehydrogenase
- In TCA-- alpha KG dehydrogenase and succinic dehydrogenase
- In PDC--lipoic acid
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