Triacylglycerols - Video Tutorials & Practice Problems
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Triacylglycerols Concept 1
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In this video, we're gonna take a look at tri ayl glycerol. Now, glycerol lipids are lipids with fatty acid chains attached to a Glycerol backbone. And when we say trio glycerol or triglycerides, this is when we have three fatty acids chains attached to the Glycerol backbone through estra bos. Now, these fatty acids can all vary in this example of our tri glycerol or triglyceride. We have our Glycerol backbone and we have connected to it, our three fatty acids, we can see that all three fatty acids are not the same. Their chain links do vary. So they don't all necessarily need to be the same. Remember if we're looking at lipids and we're breaking it down, we have lipids that are broken down into fatty acids and steroids, fatty acids are broken, broken down further into waxes or what we have here. Now, Glycerol lipids as well as two other designations which we'll talk about later on. Now, this Glycerol uh lipids you have are tri glycerol here or our triglycerides. Again, it is a Glycerol backbone with our three fatty acids, which could all be the same or be different from one another. Now, here what's the function of these triglycerides? Well, they have two main functions and they are energy source we could tap into and we're gonna say here they can act as storage in the form of adipose tissue in animals. So, just remember when we're talking about our triglycerides or our trio glycerol, we're talking about a Glycerol backbone and attached to it are three fatty acids connected by an er bond or in this case, three, bos.
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Triacylglycerols Example 1
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Here, it says, draw the triglyceride structure composed of palmitic acid for the first carbon Myristic acid for carbon two and OIC acid for carbon three. Now, based on our memory tools, we know that mic acid is a saturated fatty acid. It has 14 carbons and no py bonds, palmetto acid. It has 16 carbons and one Pyon and OIC acid has 18 carbons and one pyon. In addition to this, their one pi bonds start on carbon nine. This will become important when drawing these structures. Now, here we're going to say step one is draw the glycerol molecule and the three fatty acids we're going to place um oh groups next to the carboxyl groups of the fatty acid. So let's do that part first. So here we're gonna draw on our Glycerol molecule. We're gonna say we have ch two ch two ch two and then we have our o age groups. Now we have to draw our fatty acids. So remember our first one is an unsaturated fatty acid. We're gonna say it has 16 carbons. So 2468. Remember the first pi bomb happens on carbon nine. So 9, 1011, 1213, 1415, 16. Next we have our Mystic acid. It's unsa it's saturated. So it has 14 no pi bonds. So 2468, 1012, 14. And then finally, OIC acid has 18 carbons, 246, eight, nine is what we have are double bond 1011, 1213, 1415, 1617, 18. Now instead of oh on Glycerol, we're just gonna write an O so we're gonna take away these HS here and then do not draw oh on the fatty acids. So now it's up to us to connect for step two. We're gonna form ester bonds between the Glycerol 08 troops and the three fatty acids. So we're gonna connect the oxygens of the glycerol to the carbel carbons of the fatty acids doing this will give us our triglyceride. So we're gonna have our CH two and ach two ch two and we have 00 and then oh, here is our ester linkage. So then we're gonna draw, remember we need 16 carbons. So 24689, 1011, 1213, 1415, 16. Here we need 14 carbons, 2468, 1012, 14. And then here we need 18 carbons, 24689, 1011, 1213, 1415, 1617, 18 carbons. So this would represent our trio Glycerol molecule or triglyceride structure. This will be our final answer.
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concept
Triacylglycerols Concept 2
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Now, when it comes to fats and oils, we're gonna say that they are mixtures of different tri iso glycerol or triglyceride molecules. When it comes to fats, we're talking about in relation to animals here, they tend to have melting points that are high. We're gonna say that they are solid at room temperature. Now, in terms of their saturation, we're gonna say they have a low number of double bonds and they have their low in unsaturated fatty acids. Here, we have an example of ATRIO glycerol molecule. We can see that the top two fatty acid chains are saturated, they have no pi bonds and the bottom one is unsaturated, but it only has one double bond. Next. When we look at oils we're talking about in relation to vegetables here, we're gonna say they tend to have low melting points. We're gonna say they tend to be liquids at room temperature. We're gonna say here that they tend to have high number of p of pie bonds or double bonds and they have to, and they tend to have a high in unsaturated fatty acids. If we take a look here, we can see that the first fatty acid chain is saturated, but the next two are unsaturated. They have a lot more double bonds or pi bonds involved. This causes kinking and it kind of alters the shape of how the carbon chains align themselves because of these double bonds because you can see that the these guys are all these structures here are bending, um not in the same fashion as the top one which is saturated. This kinking and contort contorting of these chains causes them not to be able to stack as efficiently, which is why they exist more as oils than as solids. Yeah, solid fats. So just remember we have the implementation or the incorporation of pie bonds here, this is gonna cause a drop in your melting point. You'll tend to exist more as an oil. You'll have a lower melting point. We'll have these kinks as a result of all this.
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example
Triacylglycerols Example 2
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In this example question, it says which tri ayl glycerol would you expect to be liquid at room temperature? Remember, we have fats which are indicative of animals and oils which are indicative of, of vegetables and plants. Remember the more double bonds or pie bonds that we possess, then the lower our melting point will be and therefore more likely to exist as a liquid at room temperature. If we take a look at option A, we see that we have 123 double bonds or pi bonds involved. And if we look at option B, we only have one pi bond involved, the one most likely to be a liquid at room temperature would have to be option A, it possesses more double bonds which will result in more kinking of the long fatty acid chain, which will result in less stacking of these structures on top of each other. Meaning they'll exist more as a liquid at room temperature and have a lower melting point as a result, right B is less likely to be a liquid when compared to A because it has much less pi bonds or double bonds involved. So again, in this particular question. Option A is more likely to be a liquid than option B because of the presence of these pi bonds or double bonds.
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Problem
Problem
Draw a skeletal structure of a triglyceride with linolenic acid (C1) and 2 palmitoleic acids. State whether it would have high or low melting point.
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