Summary of Membrane Transport

So at this point in our course, we've covered all of the forms of membrane transport that we're going to talk about in our course. And so here in this video we're going to do a summary of membrane transport. And really, there's no new information in this video. And so, if you'd like, feel free to skip this video if you already have a good understanding of all of the different types of membrane transport. And so here we're revisiting our map of the lesson on membrane transport. And of course, we know that we explored this map by exploring the left most branches first. And so we talked about the molecular transport of small molecules distinguishing passive transport from active transport and, of course, recall that passive transport means that there's absolutely no energy required. And that's because it's moving molecules downhill down their concentration. Grady INTs from areas of high concentration down to areas of low concentration, whereas active transport, on the other hand, is going to require energy. And that's because it moves molecules uphill against their concentration radiance from areas of low concentration to areas of high concentration. And so, in terms of passive transport we talked about two main types. Simple diffusion and facilitated diffusion. Recall. Simple diffusion requires no protein mediator in order for the molecules across the membrane. And so in simple diffusion, the molecules just squeeze right between the fossil lipids to get from one side of the membrane to the other side of the membrane down their concentration. Grady INTs, whereas with facilitated diffusion, a protein mediator is required in order to allow molecules to transport across the membrane down their concentration. Grady INTs And in terms of the protein mediator, we talked about two main types. The carriers and transporters, which undergo a confirmation will change to allow molecules to transport across the membrane down their concentration. Greedy INTs. And then we also talked about porn's and channels, which do not undergo a confirmation. I'll change. Instead, they create a membrane spanning tunnel toe, allow molecules to defuse down their concentration. Grady INTs across the membrane. Now, in terms of the carriers and transporters, we talked about two specific biological examples. The Aretha Oocyte glucose unit, Porter Glute one, which allows a re throw sites to uptake glucose from the blood. And then we also talked about the Aretha recite chloride bicarbonate anti porter, which allows for the chloride shift that allows our bodies to transport mawr carbon dioxide from the tissues to the lungs, and then, in terms of the porn's and channels. We talked about five different types of ion channels, including the Leakage ion channel, which always remains open. And then we talked about these four gated ion channels, which do not always remain open. They actually open and close in response to various stimuli, the Ligand gated ion channel recall opens and closes in response to extra cellular sit lie Ganz, The signal Gated ion channel opens and closes in response to interest cellular signaling molecules. The voltage gated ion channel opens and closes in response to changes in voltage, trans membrane voltage or trans membrane potential. And then the mechanical gated ion channels open and close in response to mechanical stimuli such as touch, pressure or sound. Then, in terms of active transport, we distinguish between primary active transport, which is driven directly by a teepee and so you can see a teepee hydraulic is directly shown here and then we also distinguished secondary active transport, which is not directly driven by a TP it's indirectly driven by a teepee, hydraulic sis and actually directly driven by a Grady int. And so you can see a molecule diffuses down. It's greedy int, as another cop molecule diffuses against it's Grady int. And so, in terms of primary active transport, we talked about five types of 80 p aces. The P type V Type F type and a type 80 p aces, and the ABC transporters that you can see down below now, in terms of the P type 80 p aces, we talked about two specific biological examples. The sodium potassium pump and the circa pump or the calcium ion pump. And, of course, in terms of secondary active transport. We talked about a very specific example and the sodium glucose importer of our intestinal epithelial cell. And then, of course, after we talked about active transport, we shifted over to the final part of our map over here, which is macro molecular transport of really, really large molecules and small molecules as well. And so we distinguish between Endo Psychosis and Exocet ASUs and recall Endo Psychosis allows molecules to enter the cell, whereas Exocet ASUs allows molecules to exit the cell and in terms of Endo psychosis. We talked about three different types. Fa go psychosis or cellular eating of large solid molecules. Pena site ASUs or cellular drinking of small liquid molecules. And then receptor mediated Endo psychosis, which is really just a form of pinot site ASUs that uses receptor proteins. And then, of course, in terms of Exocet doses, we specifically talked about neurotransmitter release and those snare fusion proteins. And so, hopefully you guys can use this map of the lesson on membrane transport as a refresher in a way to summarize the membrane transport that we talked about in our previous lesson videos. And so this here concludes this video and I'll see you guys in our next one.

All right. So here we have another really interesting image that helps to summarize some not all of the forms of membrane transport that we talked about in our previous lesson videos. And so notice that the top half of this image here is dedicated to passive transport. And, of course, the bottom half of our image right here is dedicated to active transport. And so, in the passive transport, ah, section of our image noticed that we have simple diffusion shown here as number one. And of course, simple diffusion requires no protein mediation. And so these molecules are capable of squeezing between the philosophy lipids down their concentration Grady int to get from one side of the membrane to the other side of the membrane, Then notice over here. For number two, we're showing you a type of facilitated passive transport. More specifically, we're showing you a carrier slash transporter a glucose transporters such as glue one which is going to allow molecules to defuse down their concentration ingredients. Um, using a confirmation Allchin change. Then for number three over here, what we have is a type of porn or channel, specifically a potassium leakage ion channel and so notice that this allows, uh, molecules ions to defuse down their concentration. Grady INTs through a channel that is creating a membrane spanning tunnel. Instead of a confirmation, I'll change and recall leakage. Ion channels always remain open now down below in the bottom half the active transport notice over here. For number four, we're showing you a specific type off P type a TPS, the sodium potassium pump, which recall will take three sodium ions from the inside of the cell and pump them to the outside of cell and to potassium ions from the outside of the cell and pump them into the cell. And it does this as it hide. Relies is a teepee and becomes phosphor related itself now moving on to number five. Over here, what we have is another type of a TPS, the ABC Transporter, also known as an M D R transporter for multi drug resistance transporter and notice that it has these two trans membrane domains. Thes two site is Olic nucleotide binding domains, and it's capable of Hydra leasing ATP as it transports drugs and toxins outside of the cell. Then for number six over here, what we have is a type of secondary active transport, which is the sodium glucose importer, and so notice that it's capable of transporting sodium down its concentration ingredient as it transports glucose against its concentration. Grady int into the South. And so again, this image here is just meant to summarize and refresh your memories of some of the concept that we talked about in our previous lesson videos. But really, there's no new information here, and so that concludes this video, and I'll see you guys in our next video.

All right. So here we have an example problem that wants us to match each term over here on the left hand side with the correct descriptions that we have over here on the right hand side. And so, of course, there are many different ways to approach solving this problem. And so if you have your own strategy that works for you, then that's fantastic. We're just going to show you one potential way. And so, starting at the top here with a it says integral membrane protein. And you might recall from our previous lesson videos that integral membrane proteins are integrated into the membrane. And so they form lots and lots of hydrophobic interactions with the hydrophobic part of the membrane, which is the interior part of the membrane. And because they form so many hydrophobic interactions with the interior part of the membrane thes air actually going to interact very tightly with the membrane interior. And so number three here is what matches with option A. So we could go ahead and put three in here and, of course, cross three off our list. Now moving on what we have is peripheral membrane proteins and recall peripheral membrane proteins, as their name implies, remain on the periphery or on the perimeter or the border of the membrane. And so they're going to interact with the border of the membrane. And so we could go ahead and put five here for Part B and, of course, cross off five from our list. So next what we have and see is a channel and recall that channel proteins are an example of facilitated passive transport or facilitated diffusion. And so facilitated diffusion is going to match with option. See here the channel so we can put one here for the facilitated diffusion. Now next. What we have is passive transport. And, of course, passive transport we know requires absolutely no energy. And it's going to move molecules down their concentration ingredients from areas of high concentration, two areas of low concentration. And so the only answer option that suggests that there is movement from high to low concentration is options six, which says that it allows rapid movement of molecules down their concentration ingredient. So for option D, we can put six and of course, cross six off are less now. Next, What we have is active transport which you might recall, is going to require energy. And so active transport is actually going to do the opposite of passive transport and move molecules against their concentration. Grady INTs from areas of low concentration to areas of high concentration. And so, of course, options. Seven. Here, movement against the concentration radiant. It's gonna match with Option E active transport and so we can put seven right here and cross off seven from our list. Now next. What we have is the sodium, potassium, 80 p ace and, of course, the sodium potassium. 80 p ace we know is a type of P type 80 p ace that gets Foss for elated during the process of active transport. And we also know that it is an anti port that will pump three sodium ions out of the cell and to potassium ions into the cell. And so, essentially what it does is it establishes a greedy int of a new ion concentration Grady int of sodium and potassium. And so, of course, it's going to help create an electrical Grady in across the membrane in order to, uh, make the inside of the cell mawr negative with respect to the outside of the cell. Ah, lot of that has to do with the function of the sodium potassium, 80 p. S. And so 10 is gonna match with that option. And of course, we can cross off 10 Now. Next, What we have is secondary transporter. And of course, we know that secondary active transport is going to essentially have one molecule travel down its concentration, radiant as another molecule is traveling against its concentration. Radiant. And so, essentially, what it's doing is it's using the energy of one Grady int to create another Grady int. And so option two here is what matches best with the secondary active transporter here. And so we could go ahead and put to right here. Then what we have is anti Porter and recall that anti porters are going to transport two molecules in opposite directions across the membrane. And so, of course, molecules moving in opposite directions is gonna match with the anti porter here so we can put four here and cross off four from our list. Now, of course, next what? We have a sim porters and Sim porters because it starts with s that can remind us that it moves molecules in the same direction across the membrane Essence importer for the s insane. And so, of course, this is going to match with option eight moving molecules in the same direction across the membrane. So we can go ahead and put eight here, cross this off our list. And then, of course, last but not least, what we have is the ion channel, which is gonna match with our last description here. And the ion channel can either be voltage gated or lie gang gated also signal gated or mechanical gated as well. And it could also be a leakage ion channel as well. But number nine here is what's going to match best with ion channel here. And so we can cross that off our list. And now you can see that these here are the answers to our practice problem, and that concludes his practice. So I'll see you guys in our next video