15. Cytoskeleton and Cell Movement
Overview of the Cytoskeleton
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Hi in this video, we're gonna be talking about an overview of the side of skeleton. So what is this kind of skeleton? Sido skeleton? Whoa. So the side of skeleton is kind of like a country's roadways, right? So in a country people need to travel around to different cities and they need to transport goods and that's exactly what the side of skeleton does. Um for the cell. And so the side of skeleton is this intricate network of roadways essentially that go throughout the entire side of skeleton. But instead of being made of concrete, these roadways are made up of different types of protein filaments. And these protein filaments are very organized, just like our roads and we can look at a map and we can get anywhere we want to just by using our road systems the same thing as in the south. It's very organized. But unlike the roadways, the site of skeleton is dynamic. And so what this means is that it's constantly being moving and responding to the environment. So our roadways whenever we make a road or a highway that pretty much stays, they're right, like sometimes they tear down a road or two, but it's not that every single day that road is moving and changing places. The side skeleton is much more like sort of those moving staircases and harry potter. Um they're constantly moving, readjusting their directions, They can be taken apart, put back together in just a matter of seconds. And so they're constantly moving and constantly responding to their environment. So they're very organized, but their organization is constantly moving. I guess that's much more like the harry potter stairways. And so there are three main components of the side of skeleton. We have these are called intermediate filaments. Micro tubules and acting filaments sometimes acting filaments are called micro filaments. But essentially let's start with intermediate filaments here. And the purpose of this is to provide tensile strength to the nucleus. So this kind of acts like a protective cage around the around the D. N. A. Because it's around the cell and the nucleus. So it kind of protects the nucleus. Um And it provides a tensile strength meaning that if something if it gets pressed together that tensile strength is going to hold its shape. It's going to just kind of protect that D. N. A. In the nucleus from getting ripped apart just because the cell is being pressed. Then we have micro tubules and micro tubules are providing kind of the roadways. This is are those staircases. Depending on which analogy like the micro tubules are the roadways of the cell. They provide this internal framework so they kind of provide these like bridges and things throughout the cell. They keep the cell shape. They allow things to be transported across from them. Um They also play a major role in mitosis. So in cell division um they are responsible for moving that DNA around helping the cell move its shape around depending on what's going on in mitosis at the time. And then they also perform or they make up different unique structures called cilia and flag ela which we're going to talk about a lot in its own topic. Um but silly and philadelphia are pretty much, they allow for cell movement or the cell to move things outside of the environment. And so these microchip feels these are super, super, super important because they're not only acting as roadways, they provide support, they really assist in cell division and they create distinct organelles that are really important for cell movement for certain types of cells. And then we have active filaments which are also called micro filaments. Either thing, it's it's the exact same thing um whether you call it acting or micro filament. But these really line the plasma membrane and they help the um cell maintain its shape. And so if the cell shape needs to change, for instance of a cell is moving throughout the body, that cell shape needs to change a lot. Then the acting filaments are in charge of that. So here's a microscope microscope slide of the side of skeleton being labeled. So we can see acting as a red and you can see that's really close to the external part of the cell because it's lining that plasma membrane and here we have micro tubules which are labeled in green and you can see the this really intense network that's traveling throughout the entire cell. It's acting. It's providing a roadway essentially for the entire cell. And you can see it goes everywhere all the way out to the plasma membrane around the nucleus. It can be really highly isolated in some regions, but essentially it travels throughout the whole cell. So how are these side of skeleton components created? So even though there's three different filaments, and we're going to talk about each one of those individually and what the differences are the actual formation of those filaments and some of their structures are very similar, even though if some of the intricate details are different. So all of these filaments are created. So the acting filaments, intermediate filaments and the micro tubules are created through the joining of small subunits. And we call these subunits monomers. And we'll go through each monomer for each different elements called something different and we'll talk about that later. But essentially these monomers are joined together through non covalin bonds. So, remember we want these non covalin bonds because we said that the side of skeleton is dynamic so it's constantly being created and broken down. So the only way that can happen is if we do weaker bonds which are those non covalin bonds. And so there's a couple of structures that you need to know the first is going to be pro to fill a bit. And this is what happens when these monomers are joined together. So we have this monomer here and we join it to this one here and we join it to this one here and eventually you're going these long things we call proto filaments. So it's the long string of sub units that we've joined into end just like here. So we have this end connecting to this end connecting to this end and so on and so forth. And these things can be hundreds thousands of monomers long. And then when we have multiple proto filaments, often what happens in these and we'll talk about each individual case individually. But often what happens is if we get multiple proto filaments, they end up twisting around each other. Kind of like a rope where they form like this helical lattice, which kind of just like if you had two strings that you twisted them, then that's kind of what that would end up looking like. And that's very common in the side of skeletal um components. And then the last tournament you really need to know, and this one is super super important and that is called nuclear station. And essentially this is how these things get started. So, remember we're starting with these one, these individual monomers, but eventually two monomers have to come together. And this process here of the first two monomers coming together actually is really diff it's not that easy. Once two monomers are together, it's super easy to add more on. But just like getting those first two together is really difficult. And so this process here is called nuclear station, it's the initiation process. So the first time these subunits are assembled together and it's a special process that isn't actually that easy. So here's an example of nuclear nation of acting. So we have these active monomers right now, they're called G acting. And we'll explain that term later. But these are active monomers. It requires some type of energy. Like I said, it's not easy to go through nuclear nation, you're going to have some kind of energy in this case is a teepee. So eight ep it gets added to all of these G. Acting's and then it forms the nucleus ation step forms the first couple of monomers together. And then once these monomers have formed then the rest of it can be formed super easy. They just start attaching on really easy once the first few have gotten together. So, um so that is just the overview side of skeleton, the components, the intermediate filaments, micro tubules that acting will go over each one individually. And then just some introductory terms on how these filaments are formed in the cell. So with that let's move on.
Which of the following is not a component of the cytoskeleton?
What is the name of the initiation process that beings to assemble the subunits of the cytoskeleton?