Lipids

in this video, we're going to begin our lesson on lipids, and so lipids are actually a very interesting class of molecule because they're actually really, really highly diverse and both their structure and their function. And so it makes it a little bit tougher toe organize the lipids because they're so different in their structure and their function. However, one thing that all lipids have in common is that all lipids are hydro phobic biomolecules. And that means that they're going to be insoluble in water, meaning that they will not mix well with water because they are hydrophobic, or water. Fearing now, although all lipids are hydrophobic, sometimes lipids can also be what's known as an fee path IQ and anti path tickets. Just a fancy word. That means that they have both hydrophobic groups that air water fearing and hydro Filic groups that air water loving within the same molecule. And we'll be able to see examples of anti path IQ molecules as we move forward in our course. But it's important to keep in mind that although they are all hydrophobic, sometimes they could be anti Patrick. Having hydrophobic and Hydro Philip groups. Now, lipids are also really interesting category of molecule because they're unlike all of the other classes of biomolecules, which are carbohydrates, proteins and nucleic acids. And that's because carbohydrates, proteins and nucleic acids. They all use consistent monomers to build polymers. However, the lipids do not have a consistent monomer, and so they do not form long chains of polymers like Thea. Other biomolecules do. And so they are unlike the other classes of biomolecules, and they don't form long chains like what we saw in our previous videos. Now, once again, there are lots of different types and classes of lipids on, so we're not going to talk about all of the different types and classes of lipids. But we are going to talk about some of them, and so lipids include fats and oils, phosphor, a lipids, steroids and waxes. And so notice down below. In our image, we're showing you some of the types of lipids, and so here notice that we have a picture of some butter and some vegetable oil here, perhaps some olive oil, and so this represents the fats and oils and fats and oils are important for long term energy storage and animals and implants and we'll get to talk a lot more about fats and oils as we move forward in our course. So this is just ah, brief introduction to them. Now, the second type that we have here are the phosphor. So lipids which look a little bit like what we see over here. Each individual, one of these structures is a fossil lipid, and so they're a major component of cell membranes. And so we'll get to talk a lot more about fossil lipids and cell membranes as we move forward in our course. But they are a type of lipid, and then over here in the corner, what we have is an interesting looking structure which represents a steroid, and so a steroid eyes. Steroids are gonna be a n'importe component of plasma membranes as well. We'll get to talk about cholesterol and how that's an example of a steroid moving forward in our course will be able to talk about that. And then steroids can also function as hormones. For example, testosterone and estrogen you may have heard of before those air examples of steroids and examples of lipids, for that matter, and again we'll get to talk more about these as we move forward in our course. And then the last type of lipid that we're gonna be talking about moving forward in our course are the waxes. And so with waxes are going to serve in the protection and prevention of water loss. And an example of a wax is like bees wax, for instance, on DSO. Once again, we'll get to talk more about them as we move forward in our course. But for now, this concludes our introduction to lipids and some of the different types of lipids, and I'll see you all in our next video.

in this video, we're going to introduce fatty acids, and so fatty acids are defined as hydrocarbon chains of varying length with a car box Cilic acid Functional group at the very end, and so we'll be able to see some examples of fatty acids down below when we get to our image. Now, really, there are two main types of fatty acids that you all should know, and the first main type are the saturated fatty acids, which, as their name implies with the saturated. These are fully saturated with hydrogen hydrogen atoms. And so this is because they Onley contain carbon to carbon single bonds. And when they contain Onley carbon to carbon single bonds, that means that they can be fully saturated with hydrogen. Now, saturated fatty acids tend to be solids at room temperature. And so let's take a look at our example down below at the saturated fatty acids, which we have over here on the far left hand side. So these are saturated fatty acids because notice that the hydrocarbon chain that we have here, which is on Lee, made up of hydrogen and carbon atoms they're fully saturated with hydrogen. It's they have the maximum amount of hydrogen on them because notice that the carbon carbon bonds in here on Lee contain single bonds, as we mentioned up above. And so notice that, uh, this hydrocarbon chain here at the very end, it has a car box Cilic acid Group, which was right here. It's basically a car boxful group. And so that is why this is a fatty acid and it's saturated once again because the hydrocarbon chain is fully saturated with hydrogen. Now notice that over here this is another way to represent the hydrocarbon chain where each of these corners that you see here each of these points represents a carbon atom and notice that the hydrogen atoms aren't being shown. It's just another representation off the same exact molecule. That's why we have the equal sign in between them now, once again, saturated fatty acids, they tend to be solids at room temperature. Just like this butter up here, uh, butter eyes, of course. Solid at room temperature. And so that is a source of saturated fatty acids. Now, the second main type of fatty acids that you all should know are the unsaturated fatty acids. And so the unsaturated fatty acids, as their name implies, are not fully saturated with hydrogen. It's and the reason that they're not fully saturated with hydrogen is because they have the presence of at least one greater than or equal toe, one carbon to carbon double bond. And so the double bonds that are in the hydrocarbon chain. They create a bend in the chain or a kink in the chain, and the kink in the chain ultimately makes these unsaturated fatty acids liquids at room temperature instead of being solids at room temperature. And so when we take a look at our image down below, over here in the middle, notice what we're showing you as an example of unsaturated fatty acids and notice that the hydrocarbon chain that we have here is not fully saturated with hydrogen because there is a carbon to carbon double bond. And so there is. They are missing some hydrogen here at thes possessions, and so that's why they call them unsaturated because they're not fully saturated due to the presence of a double bond. Now, notice that the double bond also creates a bend in the chain. It's not straight or linear, like the saturated fatty acids are. It creates a bend or a kink in the chain. And so because it has a kink in the chain, the unsaturated fatty acids, they cannot be tightly packed together, so they're gonna remain relatively loose. And that loose nature is why they are liquids at room temperature. So these oils, vegetable oils and olive oil and things like that they are examples of unsaturated fatty acids that are liquids at room temperature. Now there is one subset of unsaturated fatty acids that air called trans fatty acids. And so you may have heard of trans fatty acids or transfats before. And really, these are a subtype of unsaturated fatty acids. That's why we have them group in the same grouping as unsaturated fatty acids. So trans fats, our artificial unsaturated fatty acids. And instead of having a kink, the the trans fats. They actually do not have a kink in their chain, so they have a double bond, But the double bond does not make them kinked, and so they remain linear. So let's take a look at the trans fatty acid, which we have down below right here, and so notice that the Trans fatty acid does have a double bond in its chain, however, notice that the double bond that's in the chain of the trans fatty acid does not create a kink in the chain or a bend in the chain. Like other unsaturated fatty acids, trans fatty acids specifically are going to have straight, uh, chains, despite having a double bond in them. Now, trans fatty acids again they are artificially made, and so you'll find them in foods like burgers and French fries and things of that nature. And so that's why we have this image right here and trans fatty acids. Usually they're associated with being very unhealthy. And so, uh, this is typically types of foods that you would want to try to avoid in your typical everyday diet on. So this year concludes our introduction to fatty acids and the difference between saturated and unsaturated fatty acids, and we'll be able to get some practice moving forward in our course. So I'll see you all in our next video

Which type of fatty acids only contain Carbon-Carbon single bonds?

a) Unsaturated.

b) Saturated.

c) Trans fats.

d) Steroids.

• A. Unsaturated.
• B. Saturated.
• C. Trans fats.
• D. Steroids.

So now that we know what fatty acids are in this video, we're going to talk about how fatty acids can be used to build another type of lipid called Trygg Lyssarides. And so try glycerin reads, as their name implies, with the try prefix here. These are lipids with three fatty acid chains, and so the try is a prefix. That means three. And that's why they have three fatty acid chains. Now these three fatty acid chains in a triglyceride are going to be co violently linked to a single glycerol molecule. Now fatty acids are going to be linked to the glycerol molecule via dehydration synthesis reactions. And so we know that dehydration synthesis reactions are used to build up a molecule. So let's take a look at our image down below to get a better understanding of this triglyceride. So notice over here on the far left, what we're showing you is a molecule and purple that represents the glycerol molecule, the single glycerol molecule that we were discussing up above here and then also notice. Over here in yellow, we have these three fatty acids and so we can go ahead and put three fatty acids here, and so notice that the fatty acids are all separate from one another here in this image and the glycerol is also separate. And so if we want to combine these separate units together and build a larger structure, then of course, we're going to need a dehydration synthesis reaction. And so notice that each of these chains thes fatty acid chains here can undergo a dehydration synthesis reaction to release three water molecules, one for each of the chains that interacts with each of these components here on the glycerol. And so you can see the O. H. Is here that react with the H is here toe form, uh, water molecules. And there are three of them that get formed. And once again, that's why we have the three out in front. Now notice Over here on the far right after the dehydration synthesis reactions, we've now combined and connected these three fatty acids co violently to the glycerol molecule. And so recall that when we have three fatty acid chains covertly linked to a single glycerol molecule, we then created a try glycerin. And so over here on the right, we have the try glycerin now, of course, if we wanted to break down the triglyceride into its separate components like what we see over here, then of course, we're going to need the hydraulics, ISS reaction. And so the hydrologists reaction eyes, of course, going to use water tow break apart, uh, triglyceride into its smaller components. Aunt triglycerides are going to be a main source of fats. This is how fats are stored in animal cells, and the facts that we have are stored as triglycerides. And so this year concludes our introduction to triglycerides. And once again, we'll be able to get some practice applying these concepts as we move forward in our course. So I'll see you all in our next video.

A triglyceride is a form of _______ composed of ___________.

a) Lipid ; fatty acids & Glucose.

b) Lipid ; Fatty acids & Glycerol.

c) Carbohydrate ; Fatty acids only.

d) Lipid ; Ribose.

• A. Lipid ; fatty acids & Glucose.
• B. Lipid ; Fatty acids & Glycerol.
• C. Carbohydrate ; Fatty acids only.
• D. Lipid ; Ribose.

in this video, we're going to introduce yet another type of lipid called the Foss photo lipid. And so phosphor Oh, lipids, as their name implies, are lipids themselves. In fact, they are a large class of lipids and also, as their name implies, with the phosphor. Oh, here These are a large class of lipids that contain a phosphate group, which recall is one of the functional groups that you all should be familiar with. And so fossil lipids are actually a major component off all cell membranes, and we'll be able to see this down below in our image. Now, later, in our course, we'll talk more details about cell membranes. But in this video we're focusing specifically on phosphor lipids. Now, fossil lipids are what we call an MFI path IQ molecules and an type. A thick recall is just a fancy word. That means that it contains both hydro filic or water loving and hydrophobic, or water fearing groups. And so foster lipids are anti patrick molecules with a hydro filic head and a hydro phobic tail hydrophobic tails, I should say, And so if we take a look at our image down below at thes fossil lipids. Notice that on the far left we're showing you a cell and we're zooming and specifically to the cells membrane, which is, uh, this little area that's right here. And when we zoom into the cells membrane, what we'll see is that the vast majority of the membrane is made up of these little structures. These little units that we see here that we call Foss follow lipids. And so if we zoom into just one of these units on, blow it up, it would look like what we see right here. And so it noticed that it really has to regions. It has this head region that's up here. And then it has the two tales that extend down below. And so the head region is a hydro filic region. Ah, hydro filic head. So this is the head, and that means that it is water loving and interacts with water. Whereas the two tales that we see down below thes are hydro phobic tales, meaning that they are water fearing. And so these tales that we see here are trying to get away from water. And so because we have a single molecule here with both hydro Filic groups and hydrophobic groups. That is why we call this an anti path IQ molecule. Now, if we were to zoom into the structure of the fossil lipid, even Mawr, we could see the details of its chemical structure which we see over here, and so notice that it does contain fatty acids, which are these yellow regions here. It also will have glycerol molecule on. Then it will also have a phosphate molecule at the top. And so this phosphate functional group is why we call them phosphor. Oh, lipids. And so really, this here concludes our introduction to foster photo lipids. And we'll be able to talk Maura about foster lipids later in our course when we're talking about cell membranes. But for now, this here concludes our introduction to fossil lipids and we'll be able to get some practice as we move forward in our course. So I'll see you all in our next video

How do phospholipids interact with water molecules?

a) The polar heads avoid water; the nonpolar tails attract water (because water is polar and opposites attract).

b) Phospholipids do not interact with water because water is polar and lipids are nonpolar.

c) The polar heads interact with water; the nonpolar tails do not.

d) Phospholipids dissolve in water.

• A. The polar heads avoid water; the nonpolar tails attract water (because water is polar and opposites attract).
• B. Phospholipids do not interact with water because water is polar and lipids are nonpolar.
• C. The polar heads interact with water; the nonpolar tails do not.
• D. Phospholipids dissolve in water.

in this video, we're going to briefly introduced to other classes of lipids the steroids and the waxes. And so steroids are a complex class of lipid that look a lot different than the other lipids that we've talked about. And that's because steroids are not made up of fatty acids. Instead, steroids are lipids that are made up of four fused carbon ring structures. And a classic example of a steroid is actually the molecule cholesterol, which you may have heard of before because cholesterol is a common steroid that's important for the structure of animal cell membranes. And so if we take a look at our image down below, over here on the left hand side, notice that here, this molecule that we're showing you is cholesterol and cholesterol is a steroid because notice that it has thes four fused carbon ring structures that we have numbered 123 and four yeah, and cholesterol. Azzawi mentioned up above is a common steroid that's important for the structure and animal cell membranes. And so, over here on the right, we're showing you a zoom in of an animal cell membrane. And so, of course, we know from our last lesson video that one of the major components of cell membranes are these Foss full lipids which were showing you over here. These all these structures are fossil lipids, but embedded within the cell membrane and embedded within thes fossil lipids are thes cholesterol molecules. So you can see the cholesterol in these positions that we see here. And so we'll get to talk Maura about the actual function of cholesterol in the cell membrane later in our course when we're focusing specifically on the cell membrane. But for now, this year concludes our introduction to steroids. Now, the other class of lipid that we're gonna briefly talk about are the waxes. And so waxes are again another class of lipid that can be used for protection purposes and also for the prevention of water loss. And so, if you take a look at the image over here on the right hand side, what we're showing you here is a structure that is a classic example of a wax. And that's because this structure is bees wax, which is why we're showing you a B over here. And so bees wax, which will notice is made up of a fatty acid. You could see a fatty acid embedded in here, but it also contains another molecule over here that used to be a long chain alcohol group. But really, the idea here is that waxes, uh, they can be used for protection purposes and prevention of water loss. And they are You need to know that waxes are a class of lipid, so both steroids and waxes are types of lipids. And really, that's the main take away here of this video. So this year concludes our introduction to steroids and waxes, and we'll be able to get some practice in our next couple of videos, so I'll see you all there.

The molecule shown the figure is a ________.

a) Fatty acid.

b) Wax.

c) Steroid.

d) Triacylglycerol.

e) Phospholipid.

• A. Fatty acid.
• B. Wax.
• C. Steroid.
• D. Triacylglycerol.
• E. Phospholipid.

Choose the correct statement about biological waxes:

a) They contain at least one steroid molecule.

b) They are fatty acids bound to long chain alcohol molecules.

c) They are extremely hydrophilic.

d) They are made of 4 fused carbon ring molecules.

• A. They contain at least one steroid molecule.
• B. They are fatty acids bound to long chain alcohol molecules.
• C. They are extremely hydrophilic.
• D. They are made of 4 fused carbon ring molecules.