7. Prokaryotic Cell Structures & Functions
Gram-Positive Cell Walls
Gram-Positive Cell Walls
Play a video:
Was this helpful?
in this video, we're going to talk more details about grand positive cell walls. And so recall from our previous lesson videos that gram positive bacteria will actually absorb and retain the gram stain unlike the gram negative cells. And also recall that grand positive cell walls are made up of a thick layer of pepto Glicken. Unlike gram negative cell walls, which have a thin layer of peptidoglycan. Now, even though grand positive cells have this thick layer of potato blight can really, really small molecules such as sugars and amino acids, they can pass freely across this thick layer of potato black and now in between the cell wall and the plasma membrane is a gel like substance that is called the peri plasm and the peri plasm is also sometimes referred to as the Perry plasvic space. It's the region that has this gel like substance. Now there are also these complex polymers of sugars that are called tech OIC uh assets and these tech OIC acids are once again, these complex polymers of sugars that are only found in the cell walls of gram positive bacteria. The Tech OIC acids are not generally found in the cell walls of gram negative bacteria. And so if we take a look at our image down below, we could get a better understanding of this overview of the grand positive cell wall structure. And so over here, notice that we're showing you a gram positive cell that has a grand positive cell wall. And of course, we know that it's going to have a thick layer of peptidoglycan, which is this layer that is in blue. And so if we zoom into this particular region, which is what you see here, you can see that the potato blight can layer is really, really thick and embedded within this potato blight can layer. You'll find these tick OIC acids which are running vertically here through this part of the image. And so once again, these tech OIC acids are these complex polymers of sugars that are only going to be found in grand positive cell walls, not in gram negative cell wall. So that is one difference that you want to make sure that you are aware of. Now also notice that in between the peptidoglycan layer that's above and the plasma membrane that's below. Right in between the two is the peri plasm and the peri plasm is also sometimes referred to as the perry plasvic space. Now, this year concludes our brief introduction to the grand positive cell walls, and we'll be able to get some practice applying these concepts as we move forward. And then we'll talk about the gram negative cell walls. So I'll see you all in our next video.
The cell wall of Gram-positive bacteria:
Contains a thin layer of peptidoglycan.
Contains a thick layer of peptidoglycan.
Is an excellent barrier to most small molecules.
Contains an outer membrane.
___________ are sugar polymers found in the cell wall of gram-positive bacteria.
Play a video:
Was this helpful?
in this video, we're going to talk more about the tech OIC acids that are found in gram positive cell walls. And so again, these Tech OIC acids are these complex polymers of molecules called glycerol, or rebuttal, that are connected by negatively charged phosphate groups. Now these negatively charged phosphate groups are going to help the Tech OIC acids act as a cat eye on reservoir and recall cat ions are ions that are positively charged. And this is because these negatively charged phosphate groups can bind to positively charged molecules such as, for example, magnesium and calcium. And so this idea here is going to be really, really important Later in our course when we talk about the gram staining procedure in detail. And so that's why we talk about it here. Now, really, there are two types of Tech OIC acids. There are what are known as wall to coke acids, which are only going to be linked to the peptidoglycan layer found in the cell wall. And then there are also lipo tech OIC acids which are going to be linked to the cell membrane of the cell. And it is going to also span the entire potato black hand layer. And so if we take a look at our image down below, we can get a better understanding of this and so notice that we're focusing in on a gram positive cell wall. And so at the top we have the potato blight, can sell wall layer here, which we know it's going to be a thick peptidoglycan layer and embedded within this thick peptidoglycan layer. We have these tech OIC acids that are running vertically here and these Tech OIC acids, there are different types. There are light boe tech OIC acids which we have here. The lipo take OIC acids are linked to the cell membrane, so you can see that there go all the way down and linked to the plasma membrane at the very very bottom. So we have those here and here as well. And then we also have the wall to co it acids, which are only linked to the peptidoglycan wall. And they do not run all the way down to the cell membrane. Now again, you can see that the peri plasm is over here, in between the potato black hand layer and the plasma membrane. And uh if we zoom into one of these tech OIC acids here, right into this region that you see right here, if we zoom into this, that's what you see right here. And you'll just see that there are complex polymers of either glycerol or rebut all that you can see is just abbreviated here, and they are linked by these phosphate groups that are in between. And so because the phosphate groups are negatively charged. Once again, this allows the Tech OIC acids to kind of act as a cat eye on um reservoir because they can bind to positively charged molecules. Now, once again, these Tech OIC acids are specific to grand positive cells. Gram negative cells do not have to cope with acids in their cell walls. And uh the gram and gram negative cells as well. See moving forward, uh the cell wall is going to be anchored to the membrane using a specific lipo protein. And again, we'll be able to talk more about this later in our course. But for now this year concludes our brief lesson on to coke acids of gram positive cell walls and we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video.
Teichoic acids are typically found:
In the cell wall of gram-negative cells.
The outer membrane of gram-negative cells.
In the cell wall of gram-positive cells.
The outer membrane of gram-positive cells.