Suppose the membrane potential for a nerve cell changed from -70.0 mV to -50.0 mV. By what factor would the relative concentration of Cl^- between the axoplasm and interstitium change, given a body temperature of 37°C? A)0.48 B)0.96 C)2.1 D)3.5

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Quizplus · Accepted Answer

The Nernst equation, which calculates the equilibrium potential for an ion based on the concentration gradient across a membrane, can be used to solve this problem. The equation in its temperature-corrected form is: E = (RT/zF) * ln([ion]outside/[ion]inside), where E is the membrane potential, R is the gas constant, T is the temperature in Kelvin, z is the charge of the ion, F is Faraday's constant, and ln is the natural logarithm. For chloride ions (Cl-) at 37°C (or 310K), the change in membrane potential from -70.0 mV to -50.0 mV indicates a change in the driving force for chloride ions. Using the Nernst equation inversely to find the change in concentration ratio, we can calculate the factor by which the relative concentration changes. The factor is approximately 2.1, indicating that the concentration gradient of Cl- across the membrane changes by a factor of 2.1 with the given change in membrane potential.

Suppose the Membrane Potential for a Nerve Cell Changed from -70.0