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  1. #1
    Roxanita is offline Senior Member
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    Membrane Transport q1 N*

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    A series of experiments is performed to determine the mechanism by which a pharmacologic agent traverses cell membranes and accumulates within target cells. The Rate of Transport depends on the concentration of the drug only. When the extracellular concentration of the agent exceeds 10 mM, no further increase in the rate of uptake is observed. Structurally similar compounds pass through the cell membrane, but at a lower rate. Oua****, an inhibitor of Na+/ K+ ATPase, fails to inhibit transport. Which of the following is the most likely mechanism by which this agent enters cells?
    A) Antiport
    B) Facilitated diffusion
    C) Ion-gated coupling
    D) Simple diffusion
    E) Symport

  2. #2
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    Asclepius1 is offline Ultimate Member 537 points
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    My guess is Symport because it saturated its co transporter.

  3. #3
    gianna01 is offline Newbie 510 points
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    An example of symport and antiport

    an example of symport, antiport, facilitated

  4. #4
    Roxanita is offline Senior Member
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    answer?

    My guess is Symport because it saturated its co transporter.
    Are you sure? if the Ouavain doesn't inhibit it, it means it doesn' require Na-K ATPase, so it's not an Active Process....let's try again

  5. #5
    enlightenedMD2B is offline Junior Member
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    simple diffusion

    ok it cant be antiport or simport because they are dependent on Na+/k+ pump
    Ion gated coupling.. whats with the similar structures crossing.. cant be that... Facilitated diffusion.same.. if it was that similar structures couldnt cross at all.. if carriers were saturated.. then the similar structure would not be able to cross either

    this leaves the correct answer from what i can tell

    [glow=red:cc8b65dac8]D) Simple diffusion[/glow:cc8b65dac8]
    becuase it depends on the gradient more.. and similar compounds may cross but the gradient for one thing doenst have anything to do with those similar compounds..
    before you criticize someone .. walk a mile in their shoes... that way you wil be a mile away ... and you will have their shoes. Hidden Content

  6. #6
    Roxanita is offline Senior Member
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    uhm...

    A series of experiments is performed to determine the mechanism by which a pharmacologic agent traverses cell membranes and accumulates within target cells. The Rate of Transport depends on the concentration of the drug only. When the extracellular concentration of the agent exceeds 10 mM, no further increase in the rate of uptake is observed. Structurally similar compounds pass through the cell membrane, but at a lower rate. Oua****, an inhibitor of Na+/ K+ ATPase, fails to inhibit transport. Which of the following is the most likely mechanism by which this agent enters cells?
    A) Antiport
    B) Facilitated diffusion
    C) Ion-gated coupling
    D) Simple diffusion
    E) Symport
    This question is from nbme so it doesn't have a pre-determined answer but for me, since this process describes Saturation Kinetics (When the extracellular concentration of the agent exceeds 10 mM, no further increase in the rate of uptake is observed.), Competition for carriers(Structurally similar compounds pass through the cell membrane), both characteristics of Protein mediated transport; but it's not dependent on ATP(Oua****, an inhibitor of Na+/ K+ ATPase, fails to inhibit transport.),...with all this for me this would be an example of FACILITATED DIFFUSION.



    Ref. kaplan Physiology pg 5

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