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The question reads:
If a neuronal membrane were to become suddenly impermeable to potassium ions but retain an active Na+/K+ ATPase, the neuron's resting potential would:
A) become more positive because potassium ion concentration would increase inside the neuron
B) become more positive because potassium ion concentration would increase outside the neuron.
C) become more negative because potassium ion concentration would increase inside the neuron.
D) become more negative because potassium ion concentration would increase outside the neuron.
The book says: A is correct. The sodium/potassium pump moves potassium inside the membrane. Potassium is positively charged making the inside of the membrane more positive. The resting potential is measured with respect to the inside.
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I don't understand this for two reasons. The first reason is that the Na/K pump is a -1 charge mechanism so even though two K+ moves in, it must have pumped three Na+'s out; so my logic would be that the overall charge must decrease.
I also don't understand it with respect to the Question 30 that reads:
The Nernst equation, when used to determine the resting membrane potential of a neuron, indicates that, as intracellular K+increases, the membrane potential:
A) stays the same.
B) changes, but not in a predictable way.
C) becomes more positive.
D) becomes more negative.
I see these two questions asking essentially the same thing so shouldn't the answer be that it becomes more negative for both of them?
Thanks for the help
If a neuronal membrane were to become suddenly impermeable to potassium ions but retain an active Na+/K+ ATPase, the neuron's resting potential would:
A) become more positive because potassium ion concentration would increase inside the neuron
B) become more positive because potassium ion concentration would increase outside the neuron.
C) become more negative because potassium ion concentration would increase inside the neuron.
D) become more negative because potassium ion concentration would increase outside the neuron.
The book says: A is correct. The sodium/potassium pump moves potassium inside the membrane. Potassium is positively charged making the inside of the membrane more positive. The resting potential is measured with respect to the inside.
-------------------------
I don't understand this for two reasons. The first reason is that the Na/K pump is a -1 charge mechanism so even though two K+ moves in, it must have pumped three Na+'s out; so my logic would be that the overall charge must decrease.
I also don't understand it with respect to the Question 30 that reads:
The Nernst equation, when used to determine the resting membrane potential of a neuron, indicates that, as intracellular K+increases, the membrane potential:
A) stays the same.
B) changes, but not in a predictable way.
C) becomes more positive.
D) becomes more negative.
I see these two questions asking essentially the same thing so shouldn't the answer be that it becomes more negative for both of them?
Thanks for the help