Transporters

Hi in this video we're gonna be talking about transporters and 80 P driven pumps. So the first class of pumps that I want to talk about, our transporters. So what our transporters will transporters are proteins that are responsible for transporting specific molecules across the membrane and they usually do this through some type of confirmation will change in the protein that allows for the molecule to pass. So um transporters can be involved in passive or active transport. And there are three types of transporters that exist in the first is a TB driven pumps which we're gonna talk about a lot. But essentially these use a G. P. To drive transport. And then there's also coupled pumps which use energy from concentration gradients of one molecule to transport another. So if there's a high concentration of one molecule it's going to easily flow through the membrane. Well that means that something else that might not have that concentration force can also be passed. So it couples it with this really high concentration gradient. Um And so you may see coupled pumps or a couple of transport being referred to as indirect active transport because it does require some type of energy right? Because it needs that concentration gradient but it's not actually requiring a teepee energy. So it's indirect. Um So to that we've talked about before but just wanna mention again here are simple ports which moved to molecules in the same direction and anti ports which moved to molecules in the opposite direction. And then finally there's this last class called light driven pumps and they use energy from light to transport molecules across the membrane. So if we're looking at the example here we have our A. T. P powered pump which you can see uses a TP to transport things across the membrane. You have your coupled pumps which come in two forms the sim porter which transports to in the same direction and you have your anti poops anti porter, let me not cross it out which transports things um in opposite directions. And then finally you have your light driven pump so that when light comes in that provides energy to transport in this case hydrogen ions across the membrane. So those are the three forms of transporters. But now I want to talk to you specifically about a couple of really important transporters that you're going to read about and you need to know about. And the first one is the sodium glucose glucose importer. So you remember sim Porter that is going to transport two molecules in the same direction across the membrane. And the sodium glucose importer allows for glucose uptake or you know, entrance into the sell side us all even. And this is really important even when concentrations are high. So even if there's a lot of glucose in the side us all the sodium glucose importer can still transport more in. And so how does it do this? Well it uses the energy from sodium um that uses that concentration gradient of sodium to trigger glucose uptake into the side of salt. So um how this works is binding of sodium it hands is the binding of glucose. And so the transporter doesn't work unless both of them are bound. And so that allows for uptake of sodium and also glucose into the cell. Now if we think about where in the body these are gonna be most useful is going to be areas of the body that need to take up a lot of glucose. So those are gonna be things their cells like gut epithelial cells. Um And it's found on the ethical surface which is gonna be the sort of I like to think of it as the top, it's not necessarily the top that it's kind of the surface that's facing inwards towards the gut. And there are different transporters that exist on the other side, right? Because it doesn't need to necessarily absorb glucose. There's but it may need to you know, let glucose out of the cell and into the bloodstream for something. Um So if we're looking at the sodium glucose transporter, what you see is that sodium is here it comes in and binds and then that triggers glucose binding into this pocket. Now that both of them are bound. There's a confirmation all change which is really common among transporters. And after this conformational change takes takes place then they can both be released into the side of saul. And so that allows for glucose uptake into the side of salt Even with there's high concentrations. Now, another one that you're gonna read about is bacterial adoption and that is a protein that uses light energy to pump hydrogen ions. So this is kind of a rare, rare protein or transporter. It's found in this arcadia commonly, there's great salt lake in Utah if you're anywhere ever been there. Um and it contains this special molecule that can sense light and once it sense light, it then provides that energy to move a proton to the cell exterior. So this is what this looks like. The light energy comes in. It is recognized by retinol and retinol allows for hydrogen to be pumped across the membrane and to the extra cellular area. So that's back to your adoption is a really important transporter. So now let's turn the page.

Hello everyone in this lesson, we are going to be talking about the different types of 80 P driven pumps. Okay, so what are 80 P driven pumps? Well these are going to be certain types of proteins that actively pump substances molecules or atoms across cell membranes and their A. T. P. Driven, which means they require that energy source a teepee. So there are four different classes of 80 P driven pumps that transport molecules against a concentration gradient or a gradient. And they do this using A T. P. So these are going to be molecules that are very important for building concentration gradients. So what they're going to be doing is they're going to be pumping a substance against its concentration gradient or against its electrical gradient or against a gradient of any kind. And in living organisms when you try to push something against a gradient, you're going to have to use energy to do that. So that's where the A. T. P. Comes into play. So this is going to be a form of primary active transport because it requires a T. P. Energy and they're going to be four different classes of these ATP driven pump. The p pumps. V pumps, f pumps and abc transporters. And we're going to go over those. So first off, let's start with the P pump. P pumps are going to be called p pumps because they have a phosphor related intermediate p pumps are phosphor related in the process of pumping ions across the plasma membrane. So these are going to be utilized to pump many different types of ions across the plasma membrane. And whenever the A. T. P. Binds with these pumps, these pumps become phosphor related and they get that phosphate group and that's why they are going to be called P pumps. They have a phosphor related intermediate. These other types of pumps do not have a phosphor related intermediate. So these P pumps are going to use that energy to pump different types of molecules or different types of ions across cell membranes. A great example of a P pump is actually going to be the sodium potassium pump, which if you don't already know what this is, this is a very, very important pump in living organisms, probably the most famous pump in living organisms. And we will definitely touch more on this topic later if we haven't already learned about it. Okay, so sodium potassium pumps are types of P pumps. Now let's move on to v pumps ve pumps are more specified than the P pumps. And that is because v pumps don't just pump many different types of ions across the cell membrane. They only transport hydrogen ions and they're going to move these hydrogen ions across different types of membranes that are called vacuole membranes. Now this looks like hey these are going to be you in the vacuole membrane in plants or other organisms which they can be utilized in the vacuole membrane but they can also be utilized in the vesicles membrane and they can also be utilized in other organelles membranes. Like the lyricism. And these V pumps are utilized to pump hydrogen ions against their gradient to build a hydrogen ion concentration which will create high acidity in certain environments like the list zone. So these V pumps are very important. These V pumps are also very important for the electron transport chain and they are going to be utilized to build that concentration of hydrogen ions which will later be utilized to build a teepee. Now these are going to be utilized to build that concentration gradients and the pumps that take advantage of that hydrogen ion concentration gradients are going to be called the F pumps and they are going to do the reverse of what the V pumps do. And what they're we're going to do is they are going to utilize those hydrogen ion concentration gradients to drive A. T. P synthesis or a synthesis. And these pumps also have another name. That's very important. They're also called a teepee synthes proteins and that is because they actually generate these 80 P molecules of energy from the proton motive force which was created by the V pumps, creating a hydrogen ion gradient. Okay, so those are very important in mitochondria and they're also very important in chloroplast. They build those 80 P. They're also found in bacterial cells and that's how they make their A. T. P. Okay, the last group of transporters, 80 P driven transporters are the A. B. C transporters. and these don't move ions. What they're going to move our small molecules and these are going to move small molecules across cell membranes or organelles membranes. And this is the largest class of 80 P transporters. And they are actually also called the abc super family. So they're a super family because it is such a huge group of proteins and this giant group of proteins is going to be found in things as small as bacteria all the way up to human beings and other mammals like ourselves. They're found in many different types of living things. Now what does A. B. C. Abc actually stand for? Because it seems kind of arbitrary but it's not it actually stands for A. T. P binding cassette transporters. So basically this name just says that this is a group of transporters that binds a teepee. So abc transporters is their name now, some important an important group of abc transporters that I want you all to know. It's going to be the multi drug resistant protein group or the M. D. R. Group. And these are going to be forms of abc transporters that move molecules across the cell membrane. But they spa's specifically move drug molecules across the cell membrane and they are going to allow certain types of cells to have drug resistance. Now these are going to be found in human beings. An example of the multi drug resistant protein class. Working in human beings is some cells have these types of proteins that actually remove chemotherapy drugs from cancer cells, which is not good for the treatment of cancer. But it's a very interesting mechanism so that you can see that they actively move drugs out of the cell to allow that cell to have drug resistance. Bacterial cells will also do this and they will also move antibiotic drugs out of the bacteria, which is also another thing that we don't particularly want. But we do have to deal with in medicine and in science. So this is a very important group, very highly studied group of abc transporters. Also another example of an abc transporter is going to be a B C four. You don't have to know this one specifically unless your professor wants you to know this is just an example. The abc four acts as a phosphor lipid flip base, which if you remember, a phosphor lipid flip base is able to transition from one side of the phosphor lipid bi layer to the other side of the phosphor lipid bi layer. And what this particular type of protein is going to do is it's going to move small molecules from one side of the cell membrane to the other side of the cell membrane. So they are a form of small molecule transporter. Now, before I finish off with this description, I want to let you know that these pumps can have different names but they will all mean the same thing. There's many different ways to identify these types of pumps. Soapy pumps can also be called P type 80 P. Aces. So an A. T. P. A. Is just gonna be a protein that utilizes a teepee. And these are P type 80 P. Aces and their transport proteins. So the same thing goes for the V pump, you can also call it A V Type A T P. Ace. So that's another name. The F pumps are generally going to be called a T. P synthesis. I don't see them called F pumps very often. A T. P synthesis is the most common name that I have seen in textbooks and in lessons. So I want you all to know that name as well. And abc transporters are generally just called abc transporter protein. They don't have another name other than that. Okay, Alright. So now I wanted to show you all what these proteins these transporters might actually look like. So you don't have to know these structures unless your professor wants you too. But most of the time you're not going to need to know these and I just wanted to show you what they're going to look like. We have the P pump here, the V pump, the F pump and the abc transporter. And as you can see they all have unique shapes and they all have unique functions and different molecules that they do move across the cell membrane and transport utilizing the help of the energy from a. T. P. Okay, everyone, let's go on to our next topic.

So in this video I'm gonna be going over a couple of examples of a teepee driven pumps. So the first one that I want to talk about is the calcium pump and this is really responsible for driving muscle relaxation. So the calcium pump is going to be a P. Class pump. Um It's found in what's known as the sarko plasmid particular. Um it's kind of a specialized form of endo plasma particular. Um And it is really responsible for causing muscle relaxation and it does this by pumping calcium from the inside of the cell and the side of saul into the circle plasmid particular um lumen. And so this calcium when it's pumped from the side is all into the lumen it causes a bunch of different signaling to happen which causes muscle relaxation. So how it happens. Um This last point as we walked through the example but calcium and a TB bind to the pump and that results in some type of confirmation will change that opens and releases calcium into the S. R. Lumen. So I don't have a great image of this. But if we have our side it's all here and our lumen on this side, calcium is going to be moving into the lumen and it's going to do it by binding um with A T. P. This isn't necessarily where it binds but just get an idea that both have to bind and this provides the energy to transport the calcium through um through to the other side into the lumen by causing some type of protein conformational change. So that's the calcium pump. Now another one that you're gonna hear a lot about is the sodium potassium pump. And of course this is gonna be responsible for moving sodium and potassium but it does so against concentration gradients. So in the side of saul there's gonna be a high amount of potassium and a low amount of sodium whereas in the extra cellular space there's gonna be a low amount of potassium and a high amount of sodium. So this pump is responsible for pumping sodium ions out and potassium ions into the cell. And every time it uses a molecule of a teepee it actually transports three sodium items ions out and two potassium ions into the cell. And so this is really important pump because it creates a steep concentration gradient of sodium across the plasma membrane which is then used by the cell for a variety of different signaling and other things that we'll talk about. So an example of this is here the sodium potassium exchange pump. You can see A. T. P. Is bound. So for every molecule of A. T. P. There's gonna be three sodium ions which you can see here 12 and three and you can see also two potassium ions 12 and the A. T. P. Becomes hydrolyzed. So it breaks apart becomes A. D. B. And that transports the sodium out of the cell and the potassium into the cell. And so eventually that's exactly what happens in the process then can repeat itself. And so um so yeah, so that is the sodium potassium pump. So now let's turn the page.

Which of the following is not considered a transporter?

• A. V ATP pump
• B. Light driven pumps
• C. Coupled pumps
• D. Ion channels

Transporters always require energy to move solutes across a membrane?

• A. True
• B. False

Which of the following classes of ATP-drive pumps can synthesize ATP when reversed?

• A. P pumps
• B. V pumps
• C. F pumps
• D. ABC Transporters

The sodium-potassium pump works by doing what?

• A. Pumping one sodium ion into the cell, while pumping one potassium ion out of the cell
• B. Pumping one sodium ion out the cell, while pumping one potassium ion into the cell
• C. Pumping three sodium ion into the cell, while pumping two potassium ion out of the cell
• D. Pumping three sodium ion out the cell, while pumping two potassium ion into the cell