Biology Forums - Study Force

activity 1
1. explain why increasing extracellular k+ reduces the net diffusion of k+ out of the neuron through the k+ leak channels.
2.explain why increasing extracellular k+ causes the membrane potential to change to a less negative value.

Question #1
- as the concentration gradient outside increases, the concentration of K+ outside the cell opposes the flow of K+ through the leak channels.

Post Merge: 10 years ago

Question# 2:
-The Nernst potential for K+ = -90mV
therefore the ion has a tendency to leak out of the channel and maintain its desired negative value. However, there are also other molecules inside and outside of the cell that have different potential values so it has to balance at a value that satisfies all of the particles inside and out.
Back to your question, when we have more positive ions on the outside of the cell the cell potential goes towards a negative value since other ions have not moved in or out to compensate the lack of positive; therefore, with more positive on the outside we get an overall negative potential value across the cell membrane.

Thank you very much!

Glad to help  ;)

needhelp87, you may mark this as solved :P