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Biochemistry

Learn the toughest concepts covered in Biochemistry with step-by-step video tutorials and practice problems by world-class tutors

11. Biological Membranes and Transport

Sodium-Potassium Ion Pump

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Sodium-Potassium Ion Pump

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in this video, we're going to begin talking about a very specific type of P type 80 p ace called the sodium potassium ion pump. And some of you guys may have already covered this pump and your previous biology courses, and so it might even be review for some of you guys. Now, what I want you guys to recall from our previous lesson videos is that the inside of cells are generally more negative with respect to the outside of the cells. And really, this is what dictates the electrical Grady int for ions. And so if we take a look at our image down below over here on the left hand side, notice that we're showing you guys this plasma membrane here for a particular cell and within this green dotted box right here, notice that we're reminding you guys that on the inside of cells they're generally mawr negative. And so you can see the negative charges here within the inside of the cell to remind you guys of that. And this is with respect to the outside of the cells, which are generally going to be more positive with respect to the inside and so This is what determines the electrical ingredient for ions. Now. Also, most cells are going to maintain an opposite lee oriented chemical, Grady int of sodium and potassium ions. And so the symbol for sodium ions is an A plus, and the symbol for potassium ions is K plus. And the way that this opposite Lee oriented chemical Grady Int works is that on the inside of the cells, there's going to be a lower sodium concentration and a higher potassium concentration with respect to the outside of the cells. And so if we take a look at our image down below right here a. To this portion, notice that on the inside of ourselves over here we have a lower sodium concentration with respect to the outside of the cell, which has a much higher sodium concentration. And we have a much higher potassium concentration on the inside of the cell and a much lower potassium concentration on the outside of the cell. And so you can see here that the sodium concentration is opposite Lee, oriented with respect to the potassium concentration. And so that's exactly what we were trying to describe up above right here and so what might help you guys remember. This particular orientation of the sodium and potassium ingredients is this image that we have over here on the right. And so really, what I think about is, I think of the cell being this really popping, super hot club that everybody wants to get into. And it's called Club Interest Cellular. And so you could see the D. J in here is playing some sick music with these strobe lights. And again, everybody wants to get into the cell and get into the club. But the sodium potassium ion pumps are really the bouncers of the cell, and so you can see that there could be several sodium potassium ion pumps in the membrane. And so, of course, went sodium tries to get its way into club intracellular. It's got to go through the bouncer here. And so the sodium ions here three of them, for that matter are asking bra. Can we enter into Club Intracellular and Party and the sodium potassium pump? Because these are sodium ions with N A, they say Nah, and so they are not able to enter the club intracellular, and so they stay on the outside And that's why the concentration of sodium is so high on the outside of the South because they can't get their way inside. Whereas when the potassium ions are trying to get into the club notice, they're saying, Hey, we're back, Let us in and the sodium potassium ion pump bouncer here because again the symbol of potassium is K. They just say, Okay, come right on into club intracellular. And that's why the sodium ion concentration on the inside of the cell is much, much higher on the inside than it is on the outside. And so we'll be able to talk about Mawr, details of the sodium potassium ion pump and how it functions and things like that in our next lesson video, So I'll see you guys there.
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concept

Sodium-Potassium Ion Pump

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in this video, we're going to talk more details about how exactly the sodium potassium ion pump works. And again, the sodium potassium ion pump is a classic example of a p type a TPS, which means that we know that at some point this sodium potassium ion pump is going to get fuss for related. But that will come a little bit later in this video. And so here. What we're saying is that the sodium potassium ion pump is again a P type 80 p ace that transports as its name implies sodium and potassium cat ions, but in opposite directions across the membrane. And because sodium and potassium are being pumped in opposite directions, this classifies the sodium potassium ion pump as an anti port. Now, the way that the sodium potassium ion pump works is that three sodium ions are going to be exported to the outside of the cell while to potassium ions are being imported to the inside of the cell. And so what helps me remember that there are three sodium ions and two potassium ions? Is that the sodium symbol here? Uh, a plus has three characters and so three sodium ions are gonna be exported, and the potassium symbol K Plus has two characters, and so to potassium ions are going to be imported. And we know that potassium is going to get imported because you could also think of, Ah, pumpkin because pump K plus in. And so we know that potassium is going to get pumped to the inside of the cell, and that's why it's being imported into the cell. Now again, the sodium potassium pump is an 80 p a. So that means that it is an 80 p dependent process and a teepee. Hydraulics. ISS is going to take place, and because it is a P type a TPS, this means that the sodium potassium pump is going to get fuss for elated. And it specifically gets fuss for related on an ISP Arctic acid residue on the pump itself. And that is what causes a confirmation all shift that allows the pump to actually transport thes ions. And we'll be able to see that down below in our images. And so over here on the left hand side of our image, what we're showing is a summarized image of the sodium potassium pump and so What you'll notice is the sodium potassium pump is this structure here that's embedded in the membrane? And, of course, we know that it is an 80 p a. So it utilizes a teepee and hide. Relies is 80 p, and more specifically, it's a P type 80 p ace, which means that it actually gets phosphor related itself during this process. And that's what we're showing here is the sodium potassium ion pump being phosphor, elated? And so what you can see here in this image is that there are three sodium ions that are going to get pumped to the outside of the cell and again on the inside of the cell. There's a low sodium concentration, and that's again because the sodium ions are constantly getting pumped to the outside of the cell, and which will also notice is that there are two potassium ions getting pumped to the inside of the cell, and that's what creates a high concentration of potassium on the inside of the cell. But how exactly does this sodium potassium pump work? Well, that's exactly what we're showing you guys over here on this right side of the image and what you'll notice is that the sodium potassium pump really works in a cycle that starts here up at the top, makes its way all the way around and then ends right back at the top where it started. And so the very first step here is that there are going to be three sodium ions that bind to the sodium potassium pump, and they bind from the inside of the cell, so they're binding here to the inside of the sodium potassium pump. Now the second step, as you can see a teepee, hydraulics is's coming into play, and so a teepee. Hydraulics, ISS. The enzyme here is going to hide, relies a teepee and in the process of the p being hydrolyzed and a Spartak acid residue on the enzyme on the sodium potassium ion pump itself is going to get phosphor elated. And so here you can see there's an ISP Arctic acid residue. You could even add that in here that is being phosphor elated. Now, in the third step, the phosphor relation is going to cause a confirmation. I'll change that is going to export the three sodium ions that pumps. And so now the three sodium ions have been released to the outside and again. That's what creates such a high concentration of sodium on the outside of the South. And so, in the fourth step right here, what you'll notice is that the potassium ion, specifically to potassium ions, are going to bind to the extra cellular side of the sodium potassium pump. And then in the fifth step here, the phosphate group that was attached is going to get removed. And so you can see that the phosphate group bond here is going to get hydrolyzed and removed from the sodium potassium pump. And so the phosphate group is removed here and in the sixth step, the removal off this phosphate group causes another confirmation will change that imports the two potassium ions that originally bound So you can see the two potassium ions, um, that are released to the inside itself. And that is what creates such a high concentration of potassium on the inside of the South. And so at this point we have the sodium potassium pump return to its original position, and so it can continue to take three mawr, uh, sodium ions and repeat this entire process and a cycle, and the sodium potassium ion pump is a pump that is usually constantly working to establish this Grady int of sodium high on the outside, low on the inside and potassium high on the inside and low on the outside. And so this video here concludes exactly how this sodium potassium ion pump works and moving forward will be able to get some practice in our next couple of videos applying these concepts so I'll see you guys in our next video.
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Problem

The critical function of the sodium-potassium pump is to move:

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Problem

Which of the following defines the type of transport by the sodium-potassium ATPase?

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Problem

Which of the following statements about the mechanism of the sodium-potassium ATPase is FALSE?

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Problem

Which of the following shows the correct order of steps for the mechanism of the sodium-potassium ATPase?

I. 2 K+ Ions bind.
II. Phosphorylation of an Asp residue.
III. Conformational change releasing 3 Na+ ions outside the cell.
IV. 3 Na+ ions bind.
V. Release of the phosphate group.
VI. Conformational change releasing 2 K+ ions inside the cell.

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