1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: 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 ?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook