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Electrogenic membrane pump

  1. May 17, 2009 #1
    1. The problem statement, all variables and given/known data

    A pump is electrogenic, meaning that 3 Na ions are pumped in for 2 K ions that pumps out. Given that the active current --> I' (Na) 30 E-9 , find the passive current of Na --> I (Na). Assume cell is in steady state so Vm, [Na] inside and [K] inside is constant.

    2. Relevant equations

    passive current Na/passive current K = active current Na/ active current of K = 3/2

    Is it possible to find a value for passive Na current if I don't know the passive current of K?

    I' (Na) / I' (K) = 3/2
    30 E-9 / I' (K) = 3/2
    I' (K) =2 E-8 , so this is the active current of K+ ion. I don't get how I can use this to find the passive current of Na
  2. jcsd
  3. May 17, 2009 #2
    actually, would this be right

    the passive current of Na is the same as the active current of Na... same magnitude, but different direction. So since give active current is +30E-9.... then I don't even need any equations to find the passive current of Na because it's simply the same but negative --> - 30E-9

    is this correct ?
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