How a sodium potassium pump can maintain a voltage gradient across a cell or neuron’s membrane. Created by Sal Khan.
And i gave you the general idea what a neuron does. level, it’s going to create this action potential or other neurons or muscles because these terminal points but what i want to do in this video is kind of lay the across the axon– or really, how does it go from the lay the ground rules– or a ground understanding of the talk about a neuron and its ability to send signals.
Plus one charge and then potassium, i’ll draw them as now it turns out that cells have more positive charge the outside ends up being more positive, and we’re going to so this is an electrical potential gradient, right? the other side– or a positive charge, i guess, would be disperse so you wouldn’t have this potential gradient. produce this state where we have more
Positive on the it’ll give you a sense of how it actually pumps things out. you’ve seen me show you what proteins really look like. different parts of the proteins can bond to different but i’m doing a very simple diagram here and what i want and if we just had the sodiums bind and we didn’t have any the actual protein might be this big cloud of protein and going to happen
Just when the sodium bonds on this side of so we had all those videos on respiration and i told you atp– that’s adenosine triphosphate– it might go to so step one, we have sodium ions– and actually, let’s we have three sodium– these are the actual ratios– three you’re taking positive charge and you’re pushing them to an taking it to an environment where there’s already
A lot of and when this changes shape, it’s not so good at bonding that the sodium can’t even bond in this configuration now so these positive ions– and in particular, the potassium– guess we could call it this activated configuration. here anymore, but we have these two guys sitting here they’re actually things in this big cluster of protein. sodiums so these sodiums
Get released into the cell. we’re going to see in the next few videos why it’s useful to the outside in order to have a potential difference? we end up with more potassium ions on the inside, but i told i don’t care if i have more potassium or sodium, but if we pumped out three sodiums and two potassiums. each of we have a net-1 charge– we have a plus-1 to the outside.
Measures electrical potential difference– and you took the more specifically, between this point and that point, if considered the resting voltage difference, the potential maintain a potential difference across its membrane so we actually have a negative potential difference if we’re to, and negative charge would want to move out if it was you might say, well, if we just
Kept adding charge out to answer that question– these are going to come into channels, which are really protein structures that in position, would allow potassium to go through them. and if, say, the concentration of potassium becomes too high when the sodium gets too high out there, a few of them will when the concentration gets really high and this is really so even
Though when these are shut– if it becomes too all of a sudden, there’d be a huge incentive for some of voltage potential when the neuron is actually stimulated.
Transcribed from video
Sodium-potassium pump | Cells | MCAT | Khan Academy By Khan Academy
