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!

How many potassium ions pass through if the ion channel opens for 1.0 {\rm ms}?

  1. Oct 28, 2012 #1
    1. The problem statement, all variables and given/known data
    The biochemistry that takes place inside cells depends on various elements, such as sodium, potassium, and calcium, that are dissolved in water as ions. These ions enter cells through narrow pores in the cell membrane known as ion channels. Each ion channel, which is formed from a specialized protein molecule, is selective for one type of ion. Measurements with microelectrodes have shown that a 0.30-nm-diameter potassium ion ({\rm{{\rm K}}}^{\rm{ + }} ) channel carries a current of 1.8 {\rm pA}.

    How many potassium ions pass through if the ion channel opens for 1.0 {\rm ms}?

    2. Relevant equations

    Delta charge (Q)=Current (I) * delta time
    1 ion = 1.6E-19 C



    3. The attempt at a solution
    Delta Q=1.8E-12*1E-3=1.8E-15C

    1.8E-15C/1.6E-19=11,250

    Mastering physics wants 2 sig figs, so entered "11,000" which is wrong.
     
  2. jcsd
  3. Oct 28, 2012 #2
    It looks right to me. Is it possible to enter "1.1e4"?
     
  4. Oct 28, 2012 #3
    That did it. Thanks for thinking of the tip!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: How many potassium ions pass through if the ion channel opens for 1.0 {\rm ms}?
Loading...