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Hello, I've come across this question and am slightly confused. The question states that for this scenario the membrane is only permeable to K+, thus would the membrane potential in this state just be the equilibrium potential of K+? If this is not the case I would not know how to calculate the resting potential. I've tried finding the individual equilibrium potential of the ions and finding the potential difference but this gives a value that would not be correct given the circumstances in the question. Anyone have any idea how to proceed?

  • $\begingroup$ Please do not post text as graphics. It discriminates against those with visual problems — especially those using screen readers — and it prevents questions being indexed. $\endgroup$
    – David
    Feb 25 at 19:51

1 Answer 1


Usually we use the Goldman Equation when calculating membrane potential with multiple ions and the Nernst equation for calculating reversal potentials for individual ions.

Try out the Goldman Equation with all these ions, setting the permeability of the ones that are zero to zero. Try the Nernst equation for potassium. You'll find that when you set the permeability to zero of all ions but one the Goldman Equation algebraically becomes the same as the Nernst equation for a single ion.




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