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Cell Biology

Learn the toughest concepts covered in Cell Biology with step-by-step video tutorials and practice problems by world-class tutors

18. Cell Junctions and Tissues

Cell-Cell Adhesion


Cell-Cell Adhesion

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Hi in this video we're gonna be talking about cell to cell adhesion. So this video is going to be a little bit boring because most of this video is just vocab words. Um so I'm gonna try to make it as interesting as possible, but a lot of this is just gonna be things you have to memorize. Um in terms you have to memorize. So cell adhesion is pretty much what that means is that neighboring cells need to stick together and so in order to stick together, they're going to have to use proteins to do it. Right? And so there's a bunch of different proteins that we're going to describe that allow these two neighboring cells to stick together. And so um why do cells need to stick together? What are some reasons for that? Well, because usually it's because they're trying to work together. So cells in the same tissue or cells in the same organ, you want those cells to stick together, You don't want your kidney cells to just kind of float off, right, you want them to stick together. And so the cell to cell adhesions make sure that these um these tissues and these organs can actually stay together and have a uniform function or at least like can work together for a single purpose. And so sales can connect in two ways, depending on the type of molecules that they use. So a home affiliate connection or homa filic adhesion um occurs when they use the same type of molecule, which makes sense. Right? We see homo all the time and that equals saying whereas hetero equals different. So a home a filic interaction uses the same molecule, this is the most common. Whereas a hetero filic is going to win, going to be when the cells use different molecules. So what this looks like is if we have cell number one and cell number two and these cells need to adhere to each other home a filic interaction will be if they both use these red lines, Hetero filic would be if this cell use the red line and this one uses this blue circle protein. So that is the first way to classify these cell cell adhesions. Whether it's homa filic, are they using the same things or is it hetero filic? Are they using different things Now. The most important one that there's tons of these molecules. I mean hundreds of these different proteins and we're not going to go through each one because we would be here for the rest of our lives. So instead we're going to focus on the important ones And the most important ones are these camps or these cell adhesion molecules and these are the ones used to connect adjacent cells. So the most important salad hetian molecule that you're going to see in your book is called a cat here in so what is a cat hearing? It's a protein but it's also a glycoprotein. You remember what glycoprotein means? It means it has a sugar on it. So this is a sugar protein. It's in the plasma membrane. Obviously if you're going to connect to cells together then the protein needs to be in the plasma membrane. So it can actually see the other cell and soak adherents. So the sugar proteins in the plasma membrane and they combined to um to connect cells together. So some interesting facts about cat hearings that I don't think that you would see on a quiz or probably not. You definitely want to quiz. They may try to trip you up and give you a really specific question on a test about these. But cat hearings they need calcium to work. So drink your milk. So your cat hearings work. Um and then there are three three main types. So those are called the E. P. And N. So endothelial placental and neural types and they have slightly different cells that they interact with. But there are so many more. I mean dozens of these nonclassical types that exist. Obviously we're not going to go through all of them don't want to keep you all day. But it is important to at least know these three names that there are three classical types into the placenta and the neural so um cat hearings if you're ever planning on taking developmental biology or if you're in a class where your professor just loves talking about development then this is an interesting fact you might want to know about and that cat hearings are really important for this thing called the epithelial mesenchymal transition and we're not in a development class. So you don't need to know what this is or how this works. But essentially it's a really important early step in development that helps us to develop properly and it helps change the sort of these mesenchymal cells um switched epithelial. So um and this process leads to the creation of important tissues like blood muscle album. But unless you're you're not gonna be tested on this in cell biology, but it is something that you will learn about if you ever take a development class. So cat hearings are the most important ones are the ones you're gonna see most often asked in the test or quiz. And here's an example of what this would look like. So we have cell number one here and we have cell number two here and there's lots of things that act in some other things over here we're not going to worry about. But essentially the cat hearings are these nice little green proteins here that are coming together. They're binding together, they're connecting themselves together just like they should. So we've talked about cat hearings as the most important ones are the ones you're gonna see most often. But there are a couple of others that are mentioned in your book. Those are elections and select in select ints. Um Instead of binding to um to themselves, they bind to sugars. So this would be an example of a hetero filic type of binding, right? And then select ins are again glycoprotein. So they're gonna be sugar proteins like the cat hearings. And they work specifically on these white blood cells, Lucas sites and endothelial cells. And because they work on white blood cells you would imagine that they're going to be really important in inflammation. And similarly to cat hearings. They have three types three classes the endothelial, the platelet and leukocyte. So the E. P. L. And sometimes if you have a really tricky professor they would like to ask. They'll ask you know what are the three classical types of cat hearings and E. P. L. Will be one of them. But remember this is for selecting not cat hearings. So make sure you get those classical types, you get those down and make sure you don't get confused about that. Um And again like before there's hundreds of these proteins we're not going to go through without all of them just mentioning the important ones but know that these aren't the only ones not just adherence, elections and selections, there's tons hundreds of these other types of cell adhesion molecules that connects cells together but we're just highlighting the important ones. So I think that's it. So um with that let's turn the page

Which of the following is not a type of cell adhesion molecules?


Which of the following CAMs work by binding to sugars on the plasma membrane in order to promote cell-cell adhesion?