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  1. #1
    Roxanita is offline Senior Member
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    Q-3) Metabolism N*

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    An increase in the activity of which of the following enzymes is most likely to increase the rate of metabolism of glucose 6-phosphate through glycolysis in the liver?

    A) Fructose 1,6-bisphosphatase

    B) Fructose 1,6-bisphosphate aldolase (aldolase A)

    C) Fructose 2,6-bisphosphatase

    D) Glucokinase

    E) 6-Phosphofructo-1-kinase

  2. #2
    Asclepius1's Avatar
    Asclepius1 is offline Ultimate Member 537 points
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    answer

    glucokinase

  3. #3
    Spartan Doc is offline Newbie 510 points
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    its Phosphofructokinase

    PFK-1 is the right answer, its the only rate-limiting enzyme of glycolysis on there...and GK is only a type of hexokinase which makes G6P in the liver....so its incorrect...the important thing about GK is that it is concentration depend (i think) cuz it has a high km value to it and is not affected by citrate and ATP, I think...someone correct me if i am wrong..
    but PFK is definitely correct....another possible answer could have been Pyruvate kinase

  4. #4
    Gingerbreadman is offline Junior Member
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    answer

    the answer is PFK-2. PFK-2 allostericly activates PFK-1 promoting its activity. Just covered that in class yesterday.

  5. #5
    Gingerbreadman is offline Junior Member
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    forgot to say this

    PFK-2 is fructose 2,6 bisphosphate

  6. #6
    Asclepius1's Avatar
    Asclepius1 is offline Ultimate Member 537 points
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    Just I wonder, where have you seen among the possible answers the variant with PFK-2? The right answer is E and only E, because:
    A. is the enzyme of Gluconeogenesis
    B. this one performs the next step of glycolysis, the splitting of Fructose 1,6-biphosphate
    C. this enzyme is active in Gluconeogenesis pathway
    D. Glucokinase is a liver enzyme, but it doesn't relate to our question, as it provides the 1st step in Glycolysis and the question is about the 3rd step.

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