Based on the Nernst equation, if the concentration of potassium outside was 3 mM and the concentration of sodium in the cytoplasm was 88 mM, what is the potassium equilibrium potential?

Question

Quizplus · Accepted Answer

The Nernst equation is used to calculate the equilibrium potential for a particular ion based on its concentration gradient across a membrane. For potassium (K+), the equation can be simplified to E_K = (RT/zF) * ln([K+]_out/[K+]_in), where R is the gas constant, T is the temperature in Kelvin, z is the charge of the ion, and F is Faraday's constant. Assuming standard body temperature (37°C, which is approximately 310K) and using the given concentrations, the calculation would yield a negative value, indicating that the equilibrium potential for potassium is negative. Among the options, -85 mV is the correct choice, as it reflects a typical potassium equilibrium potential under physiological conditions.

Based on the Nernst Equation, If the Concentration of Potassium