The inside of the neuron has a lower concentration of positive io...

Question

The inside of the neuron has a lower concentration of positive ions than the outside of the neuron. Is the membrane potential positive or negative?

Accepted Answer

Okay everyone for this practice problem, we have a membrane potential is the So we are looking for the definition of a membrane potential. Now recall that a membrane potential involves the cell membrane. So here we have a cell membrane and we have the outside of the cell and the inside of the cell. Now the membrane potential is the difference in voltage. So that's the voltage difference between the outside and the inside of the cell. And that can drive ions either into the cell or out of the cell. So let's go ahead and take a look at some of our answer options. We have a difference in electric potential between interior and exterior of a cell. Now, this does correctly describe the membrane potential because the electric potential is the voltage. So it's the difference in voltage between the interior and the exterior of the cell. But before we select this as our final answer, let's take a look at the other answer choices. So, for B, we have difference in the number of sodium and potassium ions on the outside of the cell. In this choice, it only describes the outside of a cell. And because of those keywords, we can go ahead and eliminate B. Because we know we need the difference between the inside and the outside. Then let's look at option C. Difference in the number of voltage gated sodium and potassium channels on the cell membrane option C only refers to channels on the cell membrane and not the difference again between the outside and inside. So we can eliminate option C. As well. Lastly we have D difference in the number of sodium and potassium ions in the interior of a cell, and D only mentions interior of the cell. And once again we are looking for the outside and inside difference in electric potential and therefore we can eliminate D. And now we have confirmed that option. A is the correct answer. So a membrane potential is the difference in electric potential between the interior and the exterior of a cell. Okay, everyone. I hope you found this helpful, and I'll see you soon for the next practice problem.

The inside of the neuron has a lower concentration of positive ions than the outside of the neuron. Is the membrane potential positive or negative?

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