in this video we're going to talk more details about gram negative cell walls. And so recall from our previous lesson videos that gram negative cells do not absorb or retain the gram stain unlike gram positive cells that do. And also recalled that the gram negative cell walls are going to have a thin layer of pepto Glicken instead of having a thick layer of peptidoglycan like gram positive cells do. And also recall that these gram negative cells, in addition to their plasma membrane have an additional outer membrane that gram positive cells do not have. And so this outer membrane is very important for these gram negative bacteria. And so this outer membrane is going to serve as the outermost layer for these gram negative cells and the outer membrane is actually anchored to the peptidoglycan layer via these lipoproteins. And so lipoproteins, as their name implies with the lipid and the protein, it's really just a protein with a hydrophobic lipid tail. So basically a protein with a lipid attached to it. And this lipoprotein in this case is going to serve as an anchor which is going to anchor the outer membrane to the pepto black and later. And we'll be able to see that down below in our image. And so if you take a look at this image over here, notice over here on the left, we're showing you a gram negative cell with a gram negative cell wall and notice that the peptidoglycan layer, which is the light blue layer in between is really really, really thin in comparison to the peptidoglycan layer and gram positive cells. Now, if we zoom into this specific region right here and blow it up in size, that's what we have right here. And what you'll notice is that there is a thin peptidoglycan layer that's right here. And then up at the top there is an outer membrane and this outer membrane is a second additional membrane that gram negative cells have gram positive cells do not have that additional membrane. And notice that the plasma membrane is at the very bottom. Uh down below right here which all cells have that plasma member. But notice that the outer membrane um at the top here is anchored to the peptidoglycan layer via these lipoproteins that you can see at these positions. And so these lipoproteins are going to serve as an anchor and so we can label them here as lipo proteins. And so this year concludes our brief introduction to gram negative cell walls. And we'll be able to apply these concepts and also learn more about gram negative cell walls as we move forward in our course. So I'll see you all in our next video. In this video, we're going to talk more details about gram negative cell walls. And so recall from our previous lesson videos that gram negative cells do not absorb or retain the gram stain unlike gram positive cells that do. And also recalled that the gram negative cell walls are going to have a thin layer of Pepto Glicken instead of having a thick layer of peptidoglycan like gram positive cells do. And also recall that these gram negative cells in addition to their plasma membrane have an additional outer membrane that gram positive cells do not have. And so this outer membrane is very important for these gram negative bacteria. And so this outer membrane is going to serve as the outermost layer for these gram negative cells. And the outer membrane is actually anchored to the peptidoglycan layer via these lipoproteins. And so lipoproteins, as their name implies with the lipid and the protein, it's really just a protein with a hydrophobic lipid tail. So basically a protein with a lipid attached to it. And this lipoprotein in this case is going to serve as an anchor which is going to anchor the outer membrane to the pepto black hand later. And we'll be able to see that down below in our image. And so if you take a look at this image over here, notice over here on the left, we're showing you a gram negative cell with a gram negative cell wall and notice that the potato blight can layer, which is the light blue layer in between is really really, really thin In comparison to the peptidoglycan layer and gram positive cells. Now, if we zoom into this specific region right here and blow it up in size, that's what we have right here. And what you'll notice is that there is a thin peptidoglycan layer that's right here. And then up at the top there is an outer membrane and this outer membrane is a second additional membrane that gram negative cells have. Gram positive cells do not have that additional membrane. And notice that the plasma membrane is at the very bottom uh down below right here, which all cells have that plasma member. But notice that the outer membrane at the top here is anchored to the peptidoglycan layer via these lipoproteins that you can see at these positions. And so these lipoproteins are going to serve as an anchor and so we can label them here as lipo proteins. Okay. And so this year concludes our brief introduction to gram negative cell walls. And we'll be able to apply these concepts and also learn more about gram negative cell walls as we move forward in our course. So, I'll see you all in our next video

in this video we're going to talk more details about the outer membrane of gram negative bacteria. And so unlike the cytoplasmic membranes, the outer membrane of gram negative bacteria contains light bow polly sacha rides or L. P. S. For short. And so like papa Lissack rides or LPS are a major component of the outer membrane of gram negative bacteria. Now these like bhopal is sacha rides or LPS. They are large complex molecules with both lipid and carbohydrate components. And like papa Lissack rides or LPS are also called endo toxins and they can be very damaging and deadly inside the host. And that's why gram negative bacteria can be associated with deadly bacterial infections. And so if we take a look at our image down below, we can get a better understanding of the outer membrane of gram negative bacteria. And so once again the gram negative bacteria are going to have to membranes and inner cytoplasmic plasma membrane and an outer membrane which is on the border here And so when we zoom into this region here and take a look at the outer membrane of the gram negative bacteria, which you'll notice is that it is going to contain these LPS molecules, these lipo policy Sacco rides. Or once again LPS, which and also these liberal policy cigarettes are also known as endo toxins. And so once again, the lipo polly sacha rides are only found in the outer membrane of gram negative bacteria and they are not found in gram positive bacteria. And so this year concludes our brief introduction to the outer membrane and how it contains these lipo policy Sacco ride, or LPS, or endo toxin molecules. And we'll be able to get some practice applying these concepts and learn more as we move forward. So I'll see while in our next video.

in this video we're going to talk details about the structure of lipo policy Sacco ride or LPS. Now recall from our previous lesson videos that lipo polly Sacha ride or LPS is also known as endo toxin. And so LPS or endo toxin, they actually have three structural parts that we have numbered down below 12 and three. Now, before we actually get to these structural parks, let's take a quick look at our image down below and notice on the left hand side, we're showing you an image of a gram negative bacterial cell and so recalled that the gram negative bacterial cells have an outer membrane and a thin layer peptidoglycan here in this image we're only showing you a small little bit of the thin layer of peptidoglycan. But we're showing you the outer membrane right here and recall that lipo polly sack rides are a major component of the outer membrane of gram negative cells. And so zooming into the actual like papa Lissack ride molecule. Again, you'll see that it has three structural components. And so the first structural component, number one is lipid A. And lipid A. Is going to anchor the entire like papa Lissack ride to the outer membrane lipid bi layer. And so you can see that the lipid a portion is right down below right here and its job is to literally anchor the entire life of poly sacha ride to the outer membrane. The second structural component is the Core Policy Sacco ride and the core poly sacha ride is at the core or the middle of the liberal policies Ackroyd. And so it's a structural molecule that's going to be in the middle and therefore it's going to connect the lipid a portion to the O antigen policy Sacco ride. Now the O antigen polly Sacha ride is actually the third component here. And so the O antigen policy Zachariah is going to be a sugar polymer that extends outward from the membrane. And so you can think that the O. Is for the oh and outward. And so if we take a look at the image down below, notice that right here at the core in the middle of the lipo policy accurate is where we have the core poly Sacha ride and then uh towards the top here in green, what we have is the O antigen and the O antigen is going to be pointing outwards from the cell. And so that is really the structure of the lip Upali sacra. Now the O antigen polly saccharin is actually very variable. It will change a lot depending on the specific species. And so by identifying the O antigen Polly Sacha ride that can actually be used to identify a specific species. Now, the core policy Ackroyd tends to remain relatively constant for the most part even across different species. Now one thing to note is that this lipid a portion that you see down below of the liberal policy back right. The lipid A. Is actually what is responsible for the damaging and the extremely deadly effects of like papa Lissack ride or endo toxin. And so really it's the lipid a portion that's responsible for um some bacterial infections being so deadly and so damaging. And so this year concludes our brief lesson on the structure of lipo polly Sacha right How it consists of these three components lipid A. The core poly Sacha ride and the O antigen police accurate. 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.

in this video, we're going to introduce torrents which are found in the outer membrane of gram negative bacteria. And so these parents are really just integral membrane proteins or proteins that are integrated into the outer membrane of gram negative bacteria. And they helped to facilitate passive transport of molecules across the outer membrane. Now, these porn's will actually span the entire membrane as these cylinder shaped poor ear's and they actually create an entire passageway or a tunnel through the outer membrane to allow molecules to diffuse across passively. Now these parents are always going to have identical subunits and they're going to be found in the outer membrane uh and it's going to form in groups of three. And so you'll see these three identical sub units that are going to associate with each other to form the entire poor. Um And so if we take a look at this image down below, notice that we're showing you a gram negative bacterial cell and we're focusing specifically on the outer membrane of the gram negative bacterial cell which is right here and so you can see the lip Upali sacha rides that are embedded here and here. You can also see the poor ins themselves which are these cylindrical shaped pores. And so you can see that they are forming in groups of three. There are units of three that will associate with each other to form the entire porn. And it creates a pathway for molecules to be able to diffuse across passively. And so when you zoom into the structure of the poor and you can see how it does consist of these three sub units and they associate with each other to allow for passive diffusion. And here's a top view that shows you how these uh cylindrical shaped sub units come together to create the poor for the specific molecule to diffuse across. And so this year concludes our brief introduction to these parents, and we'll be able to get some practice applying this as we move forward, so I'll see you all in our next video.