 All right, let's go ahead and take a look at the different kinds of lipids you can have. And first of all, you're probably familiar with, probably the one lipid that you're most familiar with is a fat. And I'm telling you right now, that's one kind of a lipid. And more importantly, dog pounds of a feather. Whoa, that's an arrow pointing to this word right here. This is lard. Lard is a fat. Lard is an example of a lipid that lives in the category of fats that's classified in the category of fats. And I just want you to know right now that these people are happy because they eat lard. I hope they don't eat lard like right out of the can or box. How do we eat lard? I don't know, but thank you, Lard Information Council, for sharing this information with us. Shall I tell you what a fat is? You know I shall. First of all, fats, all fats, have a glycerol, glycerol, a glycerol molecule. And then they have three fatty acids. So the fatty acids, I'm going to draw them like this. And we're actually going to look at fatty acids in the next section. So I'm not going to give you a whole lot of details about the chemical structure of a fatty acid. It's basically a carbon-hydrogen chain. But the structure of a fat is to have a glycerol and these three fatty acids. We can have saturated fatty acids or unsaturated fatty acids, but we can even have trans fatty acids. That's just one kind of a lipid. Another kind of a lipid is a phospholipid. And guess what? Do you remember what I said in the previous section? Do I remember what I said in the previous section? I don't even know if I remember what I said. But I'll tell you right now, a phospholipid has a phosphate and how many fatty acids are you going to go for? Two fatty acids, not three, just two. And phospholipids are really, really cool. But that ain't all, folks. We have another category of lipids. And this is the steroid category, steroids. Steroids are lipids? Yeah. Steroids are any molecule. It is a lipid. Lipids are essentially defined by the fact that they're hydrophobic. They don't like water, which makes complete sense if you think about salad dressing. Steroids are based on cholesterol. So if you see a molecule that looks like it might have come from cholesterol, like, oh, not those guys. That's probably what you think of, though. When you think of steroids, seriously? Dude, I could like hunt for body, look at that. Okay, settle down. This one, what? Okay, I think we have some photo shopping action happening here. This is probably what you think of when you think of steroids. So what you should think of is this right here, because that's actually a molecule of cholesterol, and a steroid is classified as a molecule that's basically built from cholesterol. There are lots of different structures that are built from cholesterol, including testosterone, estrogen, progesterone, cortisol. Those are all steroid hormones because they are built from cholesterol. Okay, what else do I need to tell you? I think that's it. So let's look closer at our fatty acids. So we're going to explore all of our possible different kinds of fatty acids, and then we're going to come back to reminding ourselves that, oh, yeah, the phospholipids are what make up the cell membrane.