Potassium Channel
This is a quick video over the potassium channel so here’s the channel right here and we will have some sodium ions which are those are potassium ions which are those and sodium which are these little green guys and it seemed like this green guy could easily fit right through this channel but that’s not the case now remember that these are charged particles so
They are positively charged and what are they floating around in well they’re actually floating around in water so we need to add water to these so we’ll add some water now we have water added to them and we’re going to say that you need four oxygen atoms four oxygen atoms for every ion ion this is an oversimplification but we’re just doing it just to show how it
Works so now this sodium it needs to have four oxygens attached to it and it can easily fit through here what happens is water actually can’t go through this tube water cannot go through can’t go through and the reason is because of these oxygen atoms right here they prevent water from going through so if water came and go through what can what’s actually these
Sodium ions are these potassium ions can so if we had a potassium right here that just randomly bumped into it and it had some water on the outside right there so as some water molecules it has four oxygen four oxygens attached are interacting with it that will balance its charge and that’s good but could we have say maybe a a what a sodium ion do this let’s draw
Up a sodium ion so sodium ion and it cannot interact with both of these it can it’s too small i can’t interact with that one and that one at the same time so it can never really get that the four oxygens that it needs to balance its positive charge so that’s why sodium can’t go through this channel only a large ion like potassium can so we had our potassium ion
Going through and started right here now it’s going to squeeze through and go right here and it’s gonna lose all its water and at this point it’s just going to keep on going through so this will be right there and when it’s passed this first step another one can come back come behind it and start interacting with it so draw the red and again these the water would
Just pop off as this one goes down and as that one goes down again so now what it would look like is this where this potassium ion is interacting with this oxygen this oxygen this one and this one where this one’s interacting with this oxygen atom this one so our potassium ion still has four oxygens interacting with it now the reason it goes down is just because
Of concentration gradients it just randomly bumps into this so let’s say you had some whoops some fasting mayans floating around and they have the water around it but i’m not going to draw the water anymore let’s say there’s also some in here it comes down to how often they’re going to hit each head it if you have one that like if there’s a lot over here then
The probability of this being hit by a potassium ion is highly likely and it will follow down the trail or if there’s aren’t too where if there aren’t too many over here they’ll just come over and diffuse away and the chances of them coming back and hitting it is low so that’s a concentration gradient basis but i just i’m not going to go too much into the actual
Concentration gradient basis i’m just going in why does it work for potassium and not sodium and it’s all about the water that is actually around each eye eye on i just want to make that clear even though sodium is smaller and it would seem like it could fit right here so if i were to draw it i think that’s nuts so if i still draw it it can’t interact with the and
With all the water or with any of the oxygens attached to the wall it can only interact with maybe one at the most and that’s not enough to the counter it’s positive charge remember oxygen is electronegative so these are negative but they have to be close to each other for them to cancel each other’s charges and these are slightly negative can’t remember the symbol
Slightly negative they’re not actually fully negative they’re slightly negative where’s this it’s a positive charge this is a positive charge and this is a positive that’s why you need four oxygens for our simplified case to count to balance out this fully charge positive ion and let’s pretend let’s first say some reason about we could even get water into this we
Still probably could not get four oxygen oxygen atoms touching this so let’s just try it see what happens so we’ll draw maybe one right there can’t fit there that’s too tight and maybe right there but the action does want to be next to those so at our most we maybe get three but it has to be it has to have four to be fully to be neutralized or else the positive
Charge is just again too strong and it doesn’t want to it doesn’t want to be just positive it was to be neutralized with a water layer around it that helps take away some of that positive charge and that’s more of just understanding how ions separated in water so so that’s why sodium can’t go through but a bigger ion like potassium can and remember potassium fits
Very well in this very well where it interacts with all the oxygens and just to be clear you can only have two potassium ions in this channel at a time you can’t have one right there because now you no longer have four oxygen atoms for every i on these this one and this one are now sharing so and that just doesn’t happen so that is a potassium channel and it’s
Basic the only thing i would add is that there are flight negative charges on the edges just slightly neat like the edges are usually slightly negatively charged and that’s to try to get these potassium ions close to it so that the chances of them actually hitting increases a lot more so if you have a little negative charge the passing must be next that negative
Charge so that’s something that’s kind of neat and that’s pretty much all for this video
Transcribed from video
Potassium Channel By Engineer Clearly