Glycerophospholipids and sphingolipids are the main membrane lipids used in biological systems and the most common types of membrane lipids are phosphatidylethanolamine and phosphatidylcholine which are both types of Glycerophospholipids and their structures can be seen here in these images below and it's worth noting that prokaryotes actually can't synthesize phosphatidylcholine and actually use a different the talk a little bit about the structure of these, Glycerophospholipids. And let's take a look at phosphatidylcholine right here. You see that, it similar to triacylglycerides, it has a glycerol backbone. Glycerol. And attached to the glycerol are 2 fatty acids. We have one here and one here. And also attached to the glycerol is a phosphate group. In the case of phosphatidylcholine, we have a choline attached to the phosphate. So that is choline right there. For phosphatidylethanolamine, we have a different molecule attached to the phosphate group but the same backbone as phosphatidylcholine, just a different molecule in the place of choline. And we also have in this image, phosphatidylserine and phosphatidylinositol which are also important membrane lipids but not the major ones. Now, sphingol for that is in their structure and you can see that is in their structure. You can see here, we have 2 sphingolipids on the right hand side of the page. And let's take a look at this sphingolipid lipid right here. So, you might notice that its structure is in some ways similar to phosphatidylcholine. We've got the choline, the phosphate group, and in this case, only one fatty acid. Fatty acid right there. Instead of glycerol and another fatty acid, we actually have this other molecule. I'm going to circle it in red. We have this molecule here and this molecule is called n came out looking weird there. Gotta start over. This is sphingosine. Right here. So overall, very similar looking structure. Right? However, little subtle differences that actually, give it different properties and therefore, it's used for different purposes. And and again, this particular molecule is sphingomyelin but all sphingolipids use a sphingazine backbone. And that is sort of the basic, difference in structures whether you have 2 fatty acids and a glycerol backbone or you're using a sphingosine backbone and only have one fatty acid? That's the basic separation between sphingolipids and glycerophospholipids. Alright. With that, let's actually turn the page.