Introduction to the Cytoskeleton - Video Tutorials & Practice Problems
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concept
Introduction to the Cytoskeleton
Video duration:
5m
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Video transcript
In this video, we're going to begin our introduction to the cytoskeleton. And so the cytoskeleton, as implied by the cyto prefix, is a network of elongated proteins that are found in the cytoplasm of a cell, and the cytoskeleton is going to have multiple different functions. Now also implied by the term cytoskeleton, it has a resemblance to our own skeletons. And so just like our skeletons gives our bodies its shape and structure, the cytoskeleton of cells does something similar, and so its functions include providing cell shape, as well as cell structure as well. But once again, we know that the cytoskeleton has multiple different functions. So not only does it provide the cell with its shape and structure, but it's also very important for cell movement, transportation, and bio signaling as well. Now, really there are 3 major components of the cytoskeleton and we've got those 3 major components numbered down below here and those are the microfilaments, the intermediate filaments, and the microtubules. And so the microfilaments are the smallest component of the cytoskeleton. They're the smallest in size and usually, microfilaments are going to be made of thin rods of repeating actin proteins. And so actin is the name of a protein that will repeatedly come together to build microfilaments. Now intermediate filaments, as their name implies, are intermediate in size. And so that means that it's going to be right in the middle. It's going to be larger than microfilaments, but smaller than the microtubules. And intermediate filaments turns out that they are made of a lot of different types of proteins, and so they can be made of variable proteins. Now the microtubules, on the other hand, are going to be the largest component of the cytoskeleton. So they are the largest in size. And as their name implies with the tubule here, they are forming these large tubes that are made up of repeating tubulin proteins. And so these tubulin proteins will repeatedly come together to build the microtubules. And so let's take a look at our image down below to get a better idea of this cytoskeleton here. And so notice that we're saying that the cytoskeleton has somewhat of a resemblance to our own skeletons here. And so you can see that through, fluorescence microscopy, we can actually turn components of the cytoskeleton different colors. Just like you can see here that the skeleton hand here is, having different colors. And so notice over here on the far left, we're showing you the microfilaments. And in this, image here, you can see that the components of the microfilaments are filled, are colored in red here. And those red, you can see, are filling up the cell, so they're found throughout the cytoplasm of the cell. And also, microfilaments are going to be the smallest in diameter as we indicated up above. So in terms of diameter, this way, they are the smallest in diameter from this end to this end right here. And so next what we have are the intermediate filaments here in the middle, and the intermediate filaments, as we indicated, are intermediate in size, so they're a little bit longer here than the microfilaments, and you can see that they are shown in green here in this image. And then the micro tubules, which are the largest in size, they're going to come together to form this large tube that you see over here, and they're also colored in green over here in this image as well. And so what you'll notice is that the cytoskeleton really fills up the entire space of the cytoplasm of a cell. And once again, it plays very very important roles for giving the cell its shape, its structure, providing movement, transportation, and biosignal. And so this here concludes our introduction to the cytoskeleton and we'll be able to apply these concepts as we move forward in our course. So I'll see you all in our next video.
2
Problem
Problem
What component of the cytoskeletons do motor proteins use to transport vesicles?
A
Actin.
B
Microfilaments.
C
Microtubules.
D
Intermediate filaments.
3
concept
Cilia & Flagella
Video duration:
3m
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Video transcript
In this video, we're going to distinguish between cilia and flagella. And so the microtubules that we introduced in our last lesson video as one of the major components of the cytoskeleton are actually a major structural component of 2 cellular structures, cilia and flagella. And both cilia and flagella provide cell movement, which means that the microtubules are very important for cell movement as we introduced in our last lesson video. And so down below, we're going to distinguish between cilia and flagella. Now cilia consist of multiple short hair like structures that move like ores and can either move objects in the surroundings relative to the cell or they can help provide cell movement itself, allowing the cell to move throughout its environment. Now flagella on the other hand, instead of being short, they are actually much longer, tail like structures that actually move like a whip in order to provide cell movement. And so flagella typically are not going to be used to move other objects in the surrounding like what cilia can sometimes be used for. Flagella are mainly used to provide cell cell movement. And so down below, we can take a look at our image to distinguish cilia and flagella. And so over here on the left hand side, we're showing you a scanning micrograph of cilia. And so you can see that these structures that you see here are the short hair like structures that we were talking about before that can move like ores in order to either move objects in the surroundings or to move the cell itself. And so, notice that there are multiple of the cilia here, and, they are shorter hair like structures. Now over here on the right hand side, we're showing you a scanning electron micrograph of some sperm cells. And so these sperm cells have flagella. And so you can see that here is the body of the cell, and the long tail that comes off of the body of the cell right here are referred to as the flagella. And so these tails are much much longer than the short cilia. And, once again, they move like whips to provide cell movement. And so this here concludes our introduction to cilia and flagella and how they're both made of microtubules, which means that microtubules are important for cell movement. And so we'll be able to get some practice applying some of the concepts that we've learned here as we move forward in our course. So I'll see you all in our next video.
4
Problem
Problem
In human cells, ___________________ are used to move a cell within its environment while ___________________ are used to move objects in the environment relative to the cell.
A
Cilia, pseudopodia.
B
Flagella; cilia.
C
Cilia; flagella.
D
Microfilaments; microtubules.
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