Question about nervous system and depolarization

[SephirothXR]

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If a cell's membrane potential changes from -60mV to -70 mV after treatment with a drug, what did the drug most likely act upon?

a)G protein
b)adenylate cyclase
c)a sodium channel
d)a potassium channel

I'm familiar with the depolarization/repolarization curve, but aren't there potassium leak channels that just let potassium slip right through anyways? It's not always the 3 Na out and 2 K in that makes the resting membrane potential -70mV, rather, it's the fact that Sodium can't leak through and Potassium can. I still got the right answer, D, but I was a little hesitant with it. Could AAMC ask a question about the leak channels? It made sense that it would have to send Postassium OUT (are there any sodium inside the neuron, or are there just more outside) since there's more of it inside, and that would be the most logical way to make a cell more negative, but I didn't know if the leak channels would just make it irrelevant.

 

[Axon hillock]

If a cell's membrane potential changes from -60mV to -70 mV after treatment with a drug, what did the drug most likely act upon?

a)G protein
b)adenylate cyclase
c)a sodium channel
d)a potassium channel

I'm familiar with the depolarization/repolarization curve, but aren't there potassium leak channels that just let potassium slip right through anyways? It's not always the 3 Na out and 2 K in that makes the resting membrane potential -70mV, rather, it's the fact that Sodium can't leak through and Potassium can. I still got the right answer, D, but I was a little hesitant with it. Could AAMC ask a question about the leak channels? It made sense that it would have to send Postassium OUT (are there any sodium inside the neuron, or are there just more outside) since there's more of it inside, and that would be the most logical way to make a cell more negative, but I didn't know if the leak channels would just make it irrelevant.

I'm not quite understanding what your question is because it seems like you understand it since you got the question right. But the Na/K is a pump so it goes against the concentration gradient. Thus, their is more Na outside the cell and more K inside the cell. To repolarize the cell the Na channels close while the K+ leak channel stay open. The MCAT could definitely ask a question about this.