in this video, we're going to talk about a classic example of primary active transport in the sodium potassium pump. And so, once again, the sodium potassium pump is a classic example of primary active transport. And as its name implies, the sodium potassium pump is going to pump or move sodium and potassium ions across the plasma membrane. But more specifically, the sodium potassium pump is going to move the sodium and potassium ions in opposite directions across the plasma membrane, which means that the sodium potassium pump is an anti porter, which recall from our previous lesson. Videos just means that some molecules will be pumped across the membrane towards the outside of the cell, whereas other molecules are going to be pumped across the membrane to the inside of the cell in opposite directions. And so that is what makes this an anti porter. Now it turns out that three sodium ions are going to be exported towards the outside of the cell, whereas to potassium ions are going to be imported towards the inside of the cell. And so what can help you remember that it's three sodium ions that are being exported? Is that the sodium here has three characters to it. It has the end. It has the A, and it has the plus. And so this, because it has three characters, can remind you that it's actually three sodium ions that are gonna be exported towards the outside of the cell. And the potassium symbol here has only two characters, so it has the K, and it has the plus, and so that can help remind you that it's too potassium ions that are being imported towards the inside of the cell. Now, what can also help you remember that potassium are going to be imported towards the inside of the cell is too? Just think of a pumpkin, because if you think about a pumpkin, it will tell you that the sodium potassium pump is going to pump K plus into the cell. And so, if you remember pumpkin, you'll remember that. Hey, potassium ions get pumped into the cell or imported into the cell. So let's take a look at our image down below to clear up some of this and notice that right here in the middle, embedded in this plasma membrane that we see right here is the sodium potassium pump right here and notice that the sodium potassium pump is going to take three sodium ions, and those three sodium ions are going to be exported towards the outside of the cell. So notice the outside of the cell is up above on this side of the membrane, whereas the inside of the cells down below. So three sodium ions are going to be pumped or exported towards the outside of the cell. And if that continuously happens over and over and over again, then there's gonna be a low concentration of sodium on the inside of the cell. So remember the brackets here represent the concentration of so we have the concentration of sodium ions on the inside of the cell is gonna be really, really low if it keeps pumping them towards the outside. And, of course, that means that on the outside, over time there's gonna be quite a high concentration of sodium ions on the outside of the cell. And as the sodium ions get pumped, of course, we know that potassium ions are also going to be pumped, but it's actually just to potassium ions that are gonna be imported on DSO. The two potassium ions get imported towards the inside of the cell, and that means that on the outside of the cell, if the potassium ions keep getting pumped in, there's gonna be a low concentration of potassium ions on the outside of the cell and on the inside of the cell. Over time, it's gonna build up, and there's gonna be quite a high concentration of potassium ions on the inside of the cell. And notice that with each pump here, three sodium out and to potassium in, uh, that a teepee hydraulics is required, and the A T P. Here is really what's providing the energy to pump these molecules against their concentration. Grady INTs from areas of low concentration towards areas of high concentration in both scenarios, so from areas of low concentration towards areas of high concentration. Uh, that requires energy, and this is primary active transport because 80 p is directly linked. Now, over here on this right side of the image, we just have another way to help you remember that. Hey, the sodium ions, they get pumped to the outside of the cell and the potassium ions they get pumped to the inside of the cell. And so you can think that the cell here is like a club. It's club interest, cellular, and so you can see that the nucleus here is like the disco D. J at the club. And you could even think that these strobe lights here kind of like the, uh the exoskeleton the sido skeleton of the cell. And so notice that the sodium potassium pump is really gonna act like these bouncers to the club. And so you can see that the sodium ions, when they try to enter the cell, they say, Bra, can we enter into the club and the sodium potassium pump? Because their sodium and they're n a the sodium potassium pump says, Nah, you can't enter, you cannot enter. And so that can help you remember that. Hey, the sodium are not going to enter the cell. They're going to get pumped towards the outside of the cell. However, when the potassium try to get into the club, uh, they say, Well, hey, we're back. Let us in and, uh, the sodium potassium pump because, uh, sodium is made up with K. They just say, Okay, come on in. And so sodium is able to get into the club really easy, and so that can help remind you that Hey, sodium, I'm sorry potassium is gonna be able to get into the cell because the sodium potassium pump says K, come on in. And the sodium over here will not be able to get into the cell, because when they try to enter the sodium potassium pump says Nah. And so this year concludes our introduction to the sodium potassium pump and how it is a classic example of primary active transport, and we'll be able to get some practice applying these concepts as we move forward throughout our course, So I'll see you all in our next video.