Membrane potential quiz?
Which ONE of the following is INCORRECT?
a. If one K+ leaves the cell and one Na+ enters at the same time, membrane potential will remain the same
b. If tons K+ channels AND many Na+ channels be open at rest, the cell would find it difficult to maintain a resting membrane potential
c. If a K+ leaves the cell, the inside of the cell becomes somewhat more negative.
d. The urge for Na+ to enter the cell is very great – both concentration gradient and membrane potential attracts Na+ entry
e. Due to the relatively hulking number of open K+ channels, the number of K+ entering the cell equals the number of K+ leaving the cell
Answers:
c is incorrect the resting potential on inside of membrane is positive
powerfully i know for a fact that C,D, and B are correct.
However, with E im pretty sure that more potassium leaks out of the membrane ( due to it mortal more permeable) so the Sodium/Potassium pump again, has to pump it back in.
So if E is proverb that due to the large number of open channels ( K+ would move into the ECF due to going to a lofty to low) i dont think it would equal to the amount coming in. More would be going out. Just like when the AP repolarizes, alot of K+ go out and causes for hypo-polarization. Source(s): Biomed student 1st year.
I reflect on this is really hard because both a and e are incorrect if we take the question at frontage value and hold your professor to his exact words. That being said, I'd say e is "more" incorrect and that's what I would answer. I would not be shocked however if you get the "wrong" answer by doing so because we need to get into the professor's head a bit to see what he's looking for.
"A" might be considered correct because one K+ out vs. one Na+ surrounded by will TEND to balance each other however, if you look at the Goldman equation (see link) its the ratio of ion in/out that matters and these ratio will not change to counteract each other exactly because their starting concentrations are different. The difference will be small however.
The answer "E" hinges on the phrase "Due to the relatively significant number of open K+ channels". The only time the K+ inflow = the K+ outflow will be at equilibrium (resting potential). At equilibrium there is a basal K+ soak resulting in K+ outflow while ion pumps will counteract this to make the inflow = outflow. It is the leak (open channels) that accounts for the outflow but not the inflow. Thus, the apology the number of K+ entering the cell equals the number of K+ leaving the cell is not due solely to open K+ channels. This interview also puzzles me because the leak/permeability is not really "open" channels if we consider open in the sense that they are maximally permeable. Source(s): http://en.wikipedia.org/wiki/Membrane_po…
I should know how to, but can't, claim particular expertise in membrane potentials. I'd be happy to see a clearer answer than mine.
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a. If one K+ leaves the cell and one Na+ enters at the same time, membrane potential will remain the same
b. If tons K+ channels AND many Na+ channels be open at rest, the cell would find it difficult to maintain a resting membrane potential
c. If a K+ leaves the cell, the inside of the cell becomes somewhat more negative.
d. The urge for Na+ to enter the cell is very great – both concentration gradient and membrane potential attracts Na+ entry
e. Due to the relatively hulking number of open K+ channels, the number of K+ entering the cell equals the number of K+ leaving the cell
Answers:
c is incorrect the resting potential on inside of membrane is positive
powerfully i know for a fact that C,D, and B are correct.
However, with E im pretty sure that more potassium leaks out of the membrane ( due to it mortal more permeable) so the Sodium/Potassium pump again, has to pump it back in.
So if E is proverb that due to the large number of open channels ( K+ would move into the ECF due to going to a lofty to low) i dont think it would equal to the amount coming in. More would be going out. Just like when the AP repolarizes, alot of K+ go out and causes for hypo-polarization. Source(s): Biomed student 1st year.
I reflect on this is really hard because both a and e are incorrect if we take the question at frontage value and hold your professor to his exact words. That being said, I'd say e is "more" incorrect and that's what I would answer. I would not be shocked however if you get the "wrong" answer by doing so because we need to get into the professor's head a bit to see what he's looking for.
"A" might be considered correct because one K+ out vs. one Na+ surrounded by will TEND to balance each other however, if you look at the Goldman equation (see link) its the ratio of ion in/out that matters and these ratio will not change to counteract each other exactly because their starting concentrations are different. The difference will be small however.
The answer "E" hinges on the phrase "Due to the relatively significant number of open K+ channels". The only time the K+ inflow = the K+ outflow will be at equilibrium (resting potential). At equilibrium there is a basal K+ soak resulting in K+ outflow while ion pumps will counteract this to make the inflow = outflow. It is the leak (open channels) that accounts for the outflow but not the inflow. Thus, the apology the number of K+ entering the cell equals the number of K+ leaving the cell is not due solely to open K+ channels. This interview also puzzles me because the leak/permeability is not really "open" channels if we consider open in the sense that they are maximally permeable. Source(s): http://en.wikipedia.org/wiki/Membrane_po…
I should know how to, but can't, claim particular expertise in membrane potentials. I'd be happy to see a clearer answer than mine.
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