Passive vs. Active Transport

All right, So in this video, we're going to distinguish between passive and active transport, which is something that you guys have done before in your previous biology courses. So again, nothing really new here. And this should be a piece of cake for you guys, and we're also going to start to explore our membrane transport map. So we know that we're going to explore this map by exploring the left most branches first. So we're gonna start with molecular transport of very small molecules. And you can see in this map here that molecular transport of small molecules can be categorized into two different groups the passive transport group and the active transport group. And again, that's the main focus of this video that there are two general types of processes that transport molecules across biological membranes, the passive transport and the active transport. Now, over here on the left hand side, what we're showing you is passive transport, which again you might recall from your previous biology courses, just means that there's going to be absolutely no energy input and so passive, uh, moving forward in our lesson. The word passive is going to mean that there is no energy input, and that's exactly what happens in passive transport. And so if there's no energy input, what this means is that molecules are gonna be defusing across the membrane as so from areas of high concentration down two areas of low concentration. Just like what you see over here in this image. Now, over here on the right hand image, what you'll notice is we've got active transport, and with active transport, you can see that the active is going to represent that there is a need for energy, and so moving forward in our lesson, active is going to be be symbolic of the requirement of energy. And so in this process, what you'll see is that usually a teepee is the molecule that provides the energy for active transport and an active transport. Instead of molecules diffusing from high to low concentration, they actually diffuse from low, too high concentration. And that's exactly what we see here with these purple molecules, their diffusing from low concentration towards the higher concentration, which is against their natural tendency. And that's why it requires energy. Now, here in our center table notice we have a table with all of these different columns here and all of these different rows here, I should say. And we've got these two columns, this one and this one and again. The blue is going to represent passive transport, and the yellow is going to represent active transport. And so, in terms of an energy input, of course, as we've already mentioned with passive transport, there's absolutely no energy input. Simple is that, and with active transport, of course, there is going to be an energy input so we can put yes, and usually that energy is coming from ATP A Z you'll see when we move forward and discuss active transport and MAWR detail. Now, in terms of the movement of the molecules relative to their Grady int in passive transport, as we already discussed, molecules are traveling down or with their concentration, Grady INTs from areas of high concentration, down two areas of low concentration. Whereas with active transport over here, of course they're going to be traveling up there Grady in or against their Grady int from areas of low concentration to areas of high concentration again, as we already indicated now, in terms of being thermo dynamically favorable because passive transport requires no energy. That means that it is indeed thermo dynamically favorable. And of course, if it's thermo dynamically favorable in terms of being spontaneous, it means that it will be spontaneous and it will be excerpt, gone IQ process and ex organic processes. We know have a negative Delta G or a negative change in Gibbs Free Energy, and this will be relevant later in our course when we're talking about how to calculate the thermodynamic favorability of membrane transport later in our course. But in terms of active transport, on the other hand, thermo dynamically favorable. We can say that it is not thermo dynamically favorable. So no, it is not thermo dynamically favorable. And that means, of course, that it will not be spontaneous. And instead of being extra chronic, it will actually be undergone yc, meaning that it will have a positive Delta G or positive change in Gibbs free energy. Now, in terms of protein facilitation, whether or not a protein is required for passive transport, the answer to that is sometimes sometimes a protein is required for passive transport to occur, and other times ah, protein is not required for passive transport whereas with active transport on the other hand, protein facilitation is always required. And so you'll be able to see over here that there is a protein here embedded in the membrane that allows for active transport to occur. And so really, what you can think of this thes two different groups of transport passive vs Active is that passive transport over here does not require energy. So it's almost like downhill movement traveling from areas of high concentration down to areas of low concentration. So because no energy is required, notice that this guy is just watching passively as the ball travels down the hill, whereas with active transport over here, notice that the transport is gonna be from low concentration to high concentrations and that is going to require energy. So you can see the guy here has to push the molecule into the area of high concentration, and that requires energy, usually in the form of ATP. Now, as we move forward in our course, we're going to break down passive transport, even mawr, and later we'll break down active transport even more so hang on tight. Let's practice the concepts that we've learned here in our next video. So I'll see you guys there

in this video, we're going to introduce the classes of passive and active membrane proteins. And so really, there are three types of passive and active membrane proteins that are classified according toe how they operate. And so the very first type here is going to be the uni porter. And so uni is a prefix that means one. And so these membrane transport proteins will Onley transport just one molecule at a time, as its name indicates, and it will transport one molecule at a time and just one direction. So pretty simple. So if you take a look down below down at Thean image, what you'll see is that number one is our unit, Porter. And as you can see, it will transport just one molecule at a time in one specific direction. Now, the second type off membrane protein that we have here is going to be the Sim Porter, and so simple porters are going to co transport at least two molecules so more than one molecule at a time in the same exact direction. And so you could think that the s in Sim port is for the S in the same direction and so when you take a look down below at our image at the CIMB Porter here, what you'll notice is it is indeed taking two molecules. Either two of the same molecules or two different molecules doesn't matter. Here we're showing two different molecules on its taking these two molecules and transporting them in the same exact direction. And this direction here and in our last type of transporter number three here. What we have is the anti Porter, and as its name implies, it's going to co transport at least two molecules just like the Sim Porter. But this time it's not transporting them in the same direction. This time it's transporting them in opposite directions. And so if we take a look down below at our image here of Number three, the anti porter notice that it is indeed transporting two molecules the red one here and the green one down here. But again, notice. This time they're not being transported in the same direction. They're actually being transported in opposite directions. And so as we move forward in our course, we're going to be able to see specific examples of each of these three different types of membrane transport proteins. And so that concludes our introduction to the classes of passive and active memory transport proteins, and I'll see you guys in our next video.