hello folks so Dr Mary here and in this video we're talking about active transporter be specific let's say active membrane transport so in previous videos we've talked about diffusion we've talked about a facilitative diffusion or to compare them because it's like simple diffusion versus facilitated diffusion those are forms of what we say is passive membrane transport right and the main thing we're saying by that is we're saying that it takes basically zero energy from the cell to actually make the transport the movement of molecules happen right so we're going to contrast that with modes of uh transport that require energy so the first one here is just we call it active transport in this situation we have membrane protein that accepts energy inputs it can use ATP to basically move molecules let's say like these Diamond molecules and in this situation removing it these molecules from a low to a high concentration that um I did pretty uh important thing because notice that this is basically going against the concentration gradient right we're going from low to high or going in other words up the concentration gradient here we're doing the opposite of diffusion right so um here we uh have to put energy to basically do what was free right and then we also have vesicular transport here this also requires energy we don't you don't see the ATP here but just assume it's being used to move things in vesicles right so together we'll call this active membrane transport active and here is basically meaning it requires energy of some sort that the cell is using right so we're going to dive into active transport here and we're going to find this actually two forms of active transport here we have primary and secondary active transport primary active transport here is kind of the situation I described earlier right you have a membrane protein here it's going to use ATP directly and it's going to move molecules across the cell membrane typically against the concentration gradient right so an example this in real life is something called the sodium potassium pump you will see this a lot when we talk about the nervous system the second form of active transport will call secondary active transport and this one is a little weird so it involves a membrane protein as before but we do not use at least a direct source of energy we don't we don't use ATP directly to make this happen what the secondary active transport uh systems or proteins do is basically rely on diffusion to drive transport of another molecule so in this example we have glucose and so here just based off the picture of this less glucose molecules here than here it's denoting that we have high concentration of glucose inside the cell a low concentration of glucose outside the cell so by normal diffusion we couldn't really move these glucose molecules inside the cell right if anything they would go the opposite direction if diffusion was allowed to curve so we see that we have this sodium here sodium ions are high in concentration here hello concentration here so what happens is we build we have a special membrane protein that accepts one sodium and one glucose and in this situation with one sodium and one glucose here both need to bind and as both bind this will create uh we'll say a conformational change in the protein shape that spits the two out on the other side here right so by doing this we um we have moved the sodium and glucose across the membrane here now here's the big trick here we're not using any energy because really what we're relying on to drive this action here is the flow sodium ions going down the concentration gradient so glucose by just pure chant and random movement movement will kind of find its way into this active site of the membrane protein here the sodium will also find their way there typically a little bit sooner because there's more sodium out here than here and with the combination of these two being plugged into both these two different active sites kind of drives the motion here so in some ways and this is the kind of weird thing wrap your head around glucose here is kind of catching a ride with the Sodium as sodium is traveling down its concentration gradient so in this form we have a little bit of facilitated diffusion with the Sodium but we're also shoveling glucose with that facilitated diffusion and so at least when it comes to glucose you can consider this secondary actor transport and we're not literally using ATP but we are supposedly using the you can kind of think as a potential energy of sodium traveling down its Concentration game this one's a little harder to kind of understand but you know review this couple more times if you have questions bring them to class and we'll deal with it but that's how secondary active transport works okay and then to wrap up oh sorry another name for secondary active transport here it's right here it's called co-transport and so this is called a sodium glucose co-transporter protein into the whole idea of code transports like you got to bring one molecule with other they're both being moved across the membrane so we call that co-transport all right so now we're on to our second active membrane transport here we're talking about vesicular uh transport here or we can break it up into their two specific version exocytosis and endocytosis these are basically to the uh they're doing the same thing but in opposite directions exocytosis is moving uh material across the cell membrane but it involves vesicles of these little sphere spheres inside the cell they can act like shipping boxes they hold material within them they're also basically made of phospholipid bilayer and that vesicle is going to move and merge with the cell membrane and then release the content of the outside world right or you have endocytosis where you something attaches cell membrane that cell membrane kind of pinches off inwards bringing the material inwards and creating a vesicle here that's endocytosis again these require ATP to make them happen but these are also forms of active membrane transport we'll see throughout the body okay folks that's all I have for you for this video in the next video actually we're actually done talking about membrane transport we're going to move on and talk about molecular genetics I'll see you for that video foreign