Neuron cells generate electrical signals by concentration gradients across membranes.Assuming a potassium ion concentration of 0.00300 M inside the cell,and a concentration of 0.135 M outside the cell,what is the electrical potential across the cell membrane? Body temperature is 310 K.The sign identifies the change in the electrical potential across the membrane and which way the ions flow.

Question

Quizplus · Accepted Answer

The correct answer is A because the electrical potential across the cell membrane is given by the Nernst equation:E = (RT/zF)ln([K+]out/[K+]in)where:E is the electrical potential in voltsR is the ideal gas constant (8.314 J/mol*K)T is the absolute temperature in Kelvin (310 K)z is the valence of the ion (1 for potassium)F is the Faraday constant (96,485 C/mol)[K+]out is the potassium ion concentration outside the cell (0.135 M)[K+]in is the potassium ion concentration inside the cell (0.00300 M)Plugging in these values, we get:E = (8.314 J/mol*K * 310 K) / (1 * 96,485 C/mol) * ln(0.135 M / 0.00300 M)E = +102 mVTherefore, the electrical potential across the cell membrane is +102 mV.

Neuron Cells Generate Electrical Signals by Concentration Gradients Across Membranes