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11. Biological Membranes and Transport

Facilitated Diffusion


Facilitated Diffusion

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all right. So now that we fully differentiated between the two different types of passive membrane transport, simple diffusion and facilitated diffusion in this video, we're going to talk more details about facilitated diffusion. And so first, we need to recall that facilitated diffusion is a type of passive transport, which, of course, means that there is no energy required. So facilitated diffusion is a non energetic type of diffusion, and as its name implies, facilitated diffusion is facilitated by a membrane protein. And really, it's this membrane protein here that differentiates facilitated diffusion from simple diffusion. Now this integral membrane protein that's involved in facilitated diffusion can either be number one a carrier slash transporter or number two a poor in slash channel. Now the carrier slash transporter is an integral membrane protein that undergoes confirmation. A little changes in order to move the salute across the membrane, whereas the porn's or channels these air integral membrane proteins that do not undergo confirmation all changes. Instead, the porn slash channels will form an obvious, membrane spanning tunnel that will allow it to move salutes across the membrane. And so if we take a look at our map down below which will notices again. We're exploring the left most branch, and we've already covered passive transport in terms of differentiating, simple and facilitated diffusion. But what you can see now in this map is that facilitated diffusion that membrane protein can either be a carrier slash transporter or a poor in slash channel. And so down below, over here on the left hand side, what we have is the carrier slash transporter. So in some of your textbooks, they'll refer to them just this. Transporters and other textbooks. They'll refer to them just as carriers. And just in general, those two terms are interchangeable for these types of membrane proteins. And so, as you can see, this is the carrier slash transporter right here, embedded in the biological membrane, and notice that there are a bunch of molecules on this side of the membrane in high concentration, and so they want to defuse down their concentration. Grady int still non energetically through the protein transporter so the molecule would bind to this transporter and then the transporter would have to undergo a confirmation will change in order to allow that molecule to be transported across the membrane, and so it will release the molecule like this, and then once it releases the molecule, it can return back to its original position to continue transporting the other molecules. But one thing to note is that when you take a look at the structure of a carrier slash transporter, there is really no clear and obvious membrane spanning tunnel. And so the really, really the Onley way that this molecule can transport molecules across the membrane is by undergoing confirmation all changes. So that's really the big take away of these carriers slash transporters that they undergo confirmation. All changes now over here on the right hand side, what we have are the parents and the channels. And so, in our previous lesson videos, we had already talked about poor ins in some of those videos, and so we know that they conform these structures here that create a a non obvious, membrane spanning tunnel. And so here we're showing a pouring. They can allow this molecule to move directly through the membrane through the tunnel that it's forming. Uh, there is no confirmation Will change that takes place with the porn's. Now Aqua Porn's are specific types of porn's that allow for water molecules to defuse at a faster rate through the membrane. And so Aqua Porn's will also come up later in our course. Aziz, we start to talk Maura, Maura about, uh, different parts of biochemistry. But Aqua Porn's theocracy part you can see is specific to water, and the poor in suggests that it's creating a poor through the membrane, a channel or tunnel through the membrane. And then over here on the far right. What we have are these ion channels, and we'll be able to talk Maura about ion channels as we move forward in our course. But they allow specific types of ions to diffuse through the membrane non energetically. And so all three of these that you see here are creating some kind of obvious membrane spanning tunnel. And so that is really what defines the porn and channels. And so as we move forward in our course, will be able to talk Maura Maura about these different types of integral membrane proteins that are involved in facilitated diffusion. But for now that concludes our introduction here to the types of membrane proteins involved in facilitated diffusion, and I'll see you guys in our next video

What type of transport does not require the assistance of a membrane protein?


Movement of water across a membrane is facilitated by proteins called _______: