Biochemistry Queston about Potassium Channels

[***]

Ok, K+ levels are high inside the cell and low outside. when a KATP channel is activated does the channel pump more potassium into the cell or is it the opposite where potassium leaks out of the cell? when the KATP channel is depolarized is that when the gradient (ratio) of intracellular potassium compared to extracellular potassium is so high that the channel opens up huge and allows the K+ to flow freely from the inside to the outside?

it has been a long time and i sold all my college text books!

karma to anyone who can help! thanks!`

 

[rjl296]

i forgot, sorry

 

[***]

i forgot, sorry

hey, at least you bumped up the thread lol

 

[oubeta]

Uh I think the answer is 4.

 

[Slowmo21]

It pumps out Na+ and in K+ in a ratio of 3:2.

As for the depolarization, it's caused by an action potential and doesn't involve the Na-K-ATPase. The membrane, or actually a small part of it, becomes passable to Na+ ions (as the channels are opened) and they flow in, thus making it so that both the inside and outiside of the cell have the same potential.

In the next phase (repolarization) K+ channels open and these ions flow outside, restoring the potential difference: inside negative and outside positive.

The amount of ions that move in and out during these phases is so small compared to the cell as a whole (all the ions in there) that you still have almost the same number of Na+ and K+ inside. Of course, the Na-K-ATPase maintains this ratio (little Na+, a lot of K+).

I know these in Finnish and tried to write them in english the best I could but there might still be some errors.
Also, I'm very early in my studies so I don't know much, meaning there may be some exceptions etc. that I don't know of. This explanation should still be more or less correct.

 

[Slowmo21]

Give me my carma!