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Martin Turner

Nernst equation and equilibrium potential

Dan Lazuran  Follow

The Nernst equation should be:

$\frac{RT}{zF}\ln\left(\frac{\mathrm{Out}}{\mathrm{In}}\right) = 2.3 \frac{RT}{zF}\log_{10}\left(\frac{\mathrm{Out}}{\mathrm{In}}\right)$

You substituted for 2.3 RT/F (approximately 60 or 61 mV: use 60 because your instructor asked you to), but forgot about z. Calcium is divalent (and positive) so for calcium z=2. Substitute this and you can see how you get your answer.

(Also note the "out/in" which is how you get negative numbers when z is positive and out < in )

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