L16 - Cells Have Ion Gradients Across the Plasma Membrane...

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Table 12-1 Essential Cell Biology (© Garland Science 2010) Cells Have Ion Gradients Across the Plasma Membrane
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RT     P K  [K + ] out   +  P Na  [Na + ] out   +  P Cl  [Cl - ] in F      P K  [K + ] in    +   P Na  [Na + ] in    +  P Cl  [Cl - ] out ln Goldman-Hodgkin-Katz Equation The membrane potential is determined primarily by the ion with the greatest permeability. V =
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Voltage-Gated Na + Channels At the resting membrane potential of the cell, Na + channels tend to remain closed. As the membrane potential rises, Na + channels become more likely to open. The result: Na + ions flow into the cell down their electrochemical gradient, driving the membrane potential even higher, thereby promoting further opening of Na + channels. However … as the membrane potential rises, K + ions will rush out of the cell, driving the membrane potential back toward its resting value. Q: Which of these opposing tendencies wins the race?
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L16 - Cells Have Ion Gradients Across the Plasma Membrane...

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