Archaeal Cell Membranes - Video Tutorials & Practice Problems
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1
concept
Archaeal Cell Membranes
Video duration:
3m
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in this video, we're going to begin our lesson on our kale cell membranes. And so our kale membrane lipids actually differ from bacterial and eukaryotic membrane lipids in two significant ways that we have number down below one and two. And so the first significant way that RKO membrane lipids differ from bacterial and eukaryotic membrane lipids is that Rko membrane lipids have hydrophobic tails that consist of repeating I saw prime lipids and these ice supreme lipids, Ice Supreme is really just a five carbon hydrocarbon molecule. And so you can see the structure of the ice supreme unit down below. And so I supreme lipids are not fatty acids and so recall that bacterial and eukaryotic membrane lipids do consist of fatty acids. And so if we take a look at our image down below, we can get a better understanding of this. And so notice on the left hand side over here, we're focusing in on the bacterial and eukaryotic membrane lipids, which mainly consist of these fossil lipids that we already discussed in our previous lesson video. They have a glycerol phosphate head group and then they have these fatty acid tails down below. Now notice that what the Rko membrane lipids which we have over here on the right that they do also have a glycerol phosphate head, just like the bacterial eukaryotic membrane lipids do however, notice looking at their hydrophobic tails that they do not consist of fatty acids. Instead the Rko membrane hydrophobic tails consist of ice Supreme chains. I supreme lipids and again, I Supreme is really just this molecule that you see here and so you can see that multiple I Supreme units are being linked together to create the hydrophobic tail. So that's one way that the two membranes different Now. The second significant way that rko membrane lipids differ from bacterial and eukaryotic membrane lipids. Um is that instead of having an ester linkage, they actually have an E ther language. And the ether linkage is what connects the hydrophobic tails to the glycerol phosphate head group. And so these ether linkages are actually more resistant to heat and chemical toxins than ester linkages are. And so this can help arcadia. Some are kev be extremophiles and be able to tolerate extreme conditions like immense amounts of heat and also high pressures and things of that nature. And so if we take a look at our image down below, once again, we can get a better understanding of this. And so notice that with the bacterial and eukaryotic membrane lipids, that there is an ester linkage highlighted here in yellow that connects the glycerol phosphate head group to the fatty acid tales. However, with the our kale membrane lipids noticed that the glycerol phosphate head group is connected to the hydrophobic tails, the US Supreme chains via N. E. Ther linkage. And so this ether linkage notice is missing a car Bonnell group. And so uh the carbonnel group that is missing here once again is what's going to allow this to become an ether linkage and make this our kale membrane lipids more resistant to heat and chemicals and things of that nature. And so this year concludes our brief introduction to RKO cell membranes and we'll be able to get some more practice applying these concepts as we move forward. So I'll see you all in our next video.
2
Problem
Problem
Cell membranes composed of glycerol-ether lipids biosynthesized from isoprene units are characteristic of:
A
Bacteria.
B
Eukayrotes.
C
Archaea.
D
Protists.
3
Problem
Problem
Which of the following statements is FALSE?
A
The hydrophobic tails of archaeal membranes are repeating isoprene units.
B
The glycerophosphate head & fatty acid tail of bacterial membranes are linked by an ester linkage.
C
The glycerophosphate head & fatty acid tail of eukaryotic membranes are linked by an ether linkage.
D
The glycerophosphate head & fatty acid tail of archaeal membranes are linked by an ether linkage.
E
The hydrophobic tails of bacterial membranes are long fatty acid chains.
4
concept
Types of Archaeal Membrane Lipids
Video duration:
4m
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in this video, we're going to talk a little bit about the different types of our kale membrane lipids. And so recall from our previous lesson video that Rko membrane lipids are made of repeating units of ice. A preen lipids rather than fatty acids, like bacterial and eukaryotic membranes are made of. Now these Rko membrane lipids that are made up of these ice supreme units can form either by layers where the membrane is made up of two layers of lipids similar to how bacteria and you carry out membranes are by layers. Or the Rko membrane lipids could form these mono layers where the membrane would consist of just one single layer of lipids. And this all depends on the type of lipid that's being used in the Rko membrane. Now the by layers are going to have to hydrocarbon ice supreme chains attached to a single glycerol phosphate head group. Uh and this is going to be formed by these specific lipids called glycerol die ether lipids notice that there's going to be just one glycerol molecule And there are going to be two Ethers to eat their linkages. So the root die is a route that means to. And so if we take a look at our image down below, over here, on the left hand side, we're showing you how our kale lipids can form by layers where there are two layers of lipids forming the membrane. So notice that here is the first layer of lipid and down below here we have the second layer of lipids forming this by layer membrane. And so this is really similar to the membranes that we saw with bacteria. And you Kariya now notice zooming into these molecules here, notice that they are separate molecules and these are glycerol diet their lipids. Again, the glycerol part means that there's only one glycerol phosphate head and the die either means that there are two ether groups, one here and one here and so this is going to be one glycerol die ether lipid. Now notice down below, we're showing you another glycerol die ether lipid because once again it has one glycerol phosphate head and to ethers. But notice that these two glycerol die ether lipids are separate from one another and that's what creates the bi layer. Now. On the other hand, the mono players are going to have to really long hydrocarbon ice supreme chains that are connected to actually to head groups. And this is going to be formed by these limp. It's called die glycerol tetra ether lipids. The Dye route once again means that there are two glycerol phosphate heads. And the tetra is a route that means four. And so they were going to be four ether linkages in this molecule. And so if we take a look at our image down below, over here, on the right hand side, notice that we're showing you and our kale lipid, how RK lipids can form a mono layer. And so notice here that instead of having two layers of lipids, there's just one single layer because these molecules are attached to each other vertically. And so notice over here, we're zooming in to show you one of these molecules, it's a die glycerol tetra either lipid. Once again, the dye route means that there are two glycerol groups or glycerol phosphate heads here and here and then the tetra is a route that means four. And so tetra ether means that there are four. Either linkages, 123 and four. Either linkages. And so notice that this is just one single molecule rather than two molecules like what we had on the left. And so this is what creates this mono layer. Now, the formation of these mono layers is going to be really critical and extremely hot temperatures because it helps to increase the membrane rigidity and therefore protect the cell in these extremely hot temperatures. And so by being capable of forming these mono layers using these die glycerol tetra ether lipids, uh these are kale membranes are going to be more resistant and allow some our kid to be extremophiles and survive in extreme conditions such as extremely hot temperatures. And so this year concludes our brief lesson on the different types of RKO membrane lipids and we'll be able to get some practice applying this concept as we move forward. So I'll see you all in our next video.
5
Problem
Problem
Thermophilic archaea may have tetraether lipids that:
A
Form bilayer membranes.
B
Form monolayer membranes.
C
Bind to and protect their DNA.
D
Form more stable tri-layer membranes.
6
Problem
Problem
Which of the following statements is true?
A
Eukaryotic cell membranes form monolayer in extremely hot temperatures.
B
Archaeal cell membranes contain cholesterol making them more rigid than eukaryotic cells.
C
Archaeal cells membranes can form bilayers or monolayers depending on environmental temperatures.
D
Bacterial cell membranes contain cholesterol making them more rigid than eukaryotic cells.
E
Bacterial cell membranes can form bilayers or monolayers.
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