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Why is the cell prefer K+ over Na+

  1. Mar 11, 2010 #1
    im asking this because chemically they are very similar, and the only big difference i see is that potassium is much larger.

    i got the details for mammalian cell typical ion concentrations and it is such:
    inside outside (mM)
    K+ 5-15 145
    Na+ 140 5

    so what does the cell has against Na?
  2. jcsd
  3. Mar 11, 2010 #2
    The gradient that is created is very important for many vital functions of our bodies to operate properly.
  4. Mar 11, 2010 #3
    if we wanted a nice gradient then taking Na out would do, but it takes in K+
  5. Mar 11, 2010 #4
    Positive feedback mechanism as well as a way to efficiently return to normal potential in the cell.
  6. Mar 11, 2010 #5

    Andy Resnick

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    Education Advisor

    Cells use *both*- it depends on what you want to move in or out of the cell. Glucose intake, for example, is coupled to sodium transport (sodium-glucose cotransporter).
  7. Mar 11, 2010 #6
    i think that the reason is that Na has a greater effect on osmosis, so by taking Na out and K in, the cell can maintain membrane structure
  8. Mar 12, 2010 #7


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    Gold Member

    A more real answer is here:
    K+ is a weak ion but more mobile than Na+.
    This is also in this bible
    pages 43 - 70
    I must Thanks Andy because he said it was a good book. (It is!)
    Last edited by a moderator: May 4, 2017
  9. Mar 13, 2010 #8
    thanks for the recommendation for the book, but i already chose albert's.

    its quite a thing molecular biology...
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