 Okay, let's talk about lipids. Lipids, I punted on my chart. I'm gonna go back to it with the other two sections, but lipids are, there's four kinds of lipids that we're gonna look at, and they don't have a consistent subunit for all of them. So I'm gonna talk about each of them separately. They're a diverse group. They're kind of a weird group for putting all together The thing all lipids have in common is that they are hydrophobic. In fact, we might even say, I'm gonna be interesting to look at this. Are all hydrophobic things lipids? Well, all lipids are hydrophobic. So find me something that's hydrophobic that isn't a lipid and tell me because I can't think of anything right now in my head. Four types of lipids. The first one I'm gonna tell you about are fats. And this is, they're also called triglycerides. And triglycerides are made of glycerol and then they're made of these three tri fatty acids. And I'm gonna show you, I'm gonna talk more about triglycerides and those fatty acid tails. We're gonna see fatty acid tails in other of our groups, but hold on for just a second and I'll talk a little bit more about these guys. They're the most common lipid that we think of when we think of lipids, we think of fats. We think of triglycerides. And so they're pretty familiar to us. Another group that will become familiar to you is a phospholipid. And a phospholipid is made of a phosphate and again, get cozy because we're gonna see a lot of phosphates and two fatty acid tails. Phospholipids are super interesting because they do have a hydrophobic part and those fatty acid tails are hydrophobic but they also have a hydrophilic part. That phosphate is hydrophilic, which is weird. This molecule of phospholipid has both a hydrophobic part and a hydrophilic part. Molecules that are like that are called amphipathic and phospholipids are the primary molecule that make up a cell membrane. So we're gonna see gajillions and frenillions of phospholipids when we get into the next section and finally start talking about living things and cells. We'll put these phospholipids together. Think about it. If you have a hydrophobic part, a part of this molecule that doesn't like water and a part that does like water, if you throw a bunch of those clowns into water, they're going to arrange themselves in a way that puts all the hydrophobic heads touching the water and all the hydrophobic tails away from the water and they actually will self organize into spheres. Cell shaped structures. So phospholipids are like ridiculously cool kind of lipid that we are gonna spend just a ton of time talking about. Okay, it might surprise you to learn that steroids are lipids. And you probably are like, dude, what steroids? They make me strong. Awesome, true. Anabolic steroids are a type of steroid but in this context, steroids are lipids that are built. Anything that is built from cholesterol is a steroid. So anabolic steroids are actually testosterone but you can also, as steroid hormones you have lots and lots of steroid hormones including estrogen and progesterone. All those molecules begin with a molecule of cholesterol which is this hydrophobic lipid. And then they're slightly modified and you end up with these super amazing hormones that do very important work in our body. Not all steroid hormones are associated with the reproductive system. There are hormones, aldosterone is one, it's produced in the kidney and it regulates blood pressure, plays a role in water concentration and that is not a reproductive related hormone. I just thought of another thing, cholesterol is an important molecule found also in the cell membrane and it actually helps the cell membrane be waterproof. So it prevents, you put more cholesterol in your cell membrane and less water can get in and out of the cell which can be handy for places like kidneys. And it can make your cell membrane more stable. So a cell membrane with a bunch of cholesterol in it can be really stable. We often think of cholesterol as a bad thing. You try to avoid it. Your body makes it, your liver makes most of the cholesterol that you need and that you have in your body. And as you can see, it's super important because it plays a role in your cell membranes and is involved in hormone production, whatever. The last group, I'm going to say one thing about waxes are waterproof. You find them on feathers and leaves to help keep feathers and leaves waterproof and to keep them from losing too much water if you're a leaf. They're a weird molecule. That's all I'm going to tell you about them. Those are our four, I do want to show you something. Our four categories of lipids. And I said I was going to go back to fats. And I want to go back to fats to look at those fatty acids. I want to show you something that you may have some familiarity with around fatty acids. And so I don't know if you've heard of this before, but you can have saturated fatty acids or unsaturated fatty acids. And this is a really interesting concept that's related to whether or not. Now look, these are fatty acid tails that I'm showing you here. And you can see that all they are are these giant strings of carbons and hydrogens. In a saturated fatty acid tail, every single carbon has a single bond to every other carbon. Like the chain has nothing but single bonds between the carbon molecules, atoms. Carbon is an atom. In an unsaturated fatty acid, you actually have double bonds between the carbon atoms. Now look, if you have a double bond between the carbon atoms, you end up with not as many hydrogens as you could have had. So you're unsaturated with hydrogen atoms. And look at the structural consequence of adding a double bond. You actually bend the fatty acid. The fatty acids that are bent, this is so cool. The fatty acids that are bent have a harder time becoming solid. Saturated fatty acids become solid really easy. At room temperature, they're gonna be solid like butter, lard. Animal fat is mostly saturated. Plant fat is mostly unsaturated. Oils that don't become solid unless you stick them in the refrigerator and get them really, really cold. I just have to tell you this little fast fact about fatty acids. Humans in our brilliance decided that vegetable fats are better than animal fats. So unsaturated fatty acids are better. And there is some truth to that. So they decided, but they liked solid fat. So they decided to hydrogenate vegetable oil and make it solid. So they added hydrogen atoms to our unsaturated fatty acids. And sometimes you would end up with trans fats. And look at the difference. We have in this trans fat, you can see that we do have a double bond. But the two hydrogens connected like surrounding that double bond are on opposite sides of the molecule and the molecule lays flat like a saturated fat, Crisco. As opposed to the hydrogen atoms being on the same side of the double bond, that's considered a cis fatty acid as opposed to a trans fatty acid. Trans fats are not preferred. They have been associated with stuff that I am not gonna know about right now, but I know that I tried to avoid trans fats. Cause they act like saturated fats and saturated fats we try to limit as well. Okay, when you learn about that from your nutrition class, tell me more. Okay, bye.