BIOL 1117 Lecture Notes - Resting Potential, Cell Membrane, Electric Field
7 Feb 2014
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Document Summary
If charges are opposite, current will bring them together; but if charges are the same, then the current will separate them voltage (or electrical potential)/resistance = current (v/r = i) For given r, if increase v increase i. Membrane is most leaky to k+ because a few k+ channels stay open even at rest cytoplasmic anions can not escape due to size or charge (phosphates, small organic acids, proteins, atp, and rna) K+ leaks out due to diffusion down concentration gradient negative electrical charge of icf starts to attract k+ back in and equilibrium is reached and net diffusion of k+ outward stops. Movement of k+ ions out of cell due to concentration gradient is now equal but opposite the movement back in of k+ due to the electrical gradient which attracts positive ions back towards negative charge of cell. The membrane potential is now negative enough to produce opposite but equal flux to concentration gradient.
