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Biochemistry

Learn the toughest concepts covered in Biochemistry with step-by-step video tutorials and practice problems by world-class tutors

10. Lipids

Omega-3 Fatty Acids

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Omega-3 Fatty Acids

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in this video, we're going to introduce and begin our lesson on omega fatty acids. And so before we start, I want to point out this alternate version of our original lipid map, which is really only here to remind us that we're still talking about fatty acids here in this lesson. And we have not yet moved on from talking about fatty acids and also just as a reminder. We're not going to talk about the Isa Perrin lipids over here until after we finished talking about all of the fatty acids and the fatty acid based lipids. And so again, omega fatty acids air just a type of fatty acid. And omega is a Greek symbol that looks like this, and so omega fatty acids. All they really are are just unsaturated fatty acids that are classified by the first double bond but numbering from the omega carbon and so, typically with fatty acids, we number the fatty acid carbon atoms starting from the carb oxalic acid carbon, and we give this the lowest number and we number around this way. However, when it comes to omega fatty acids, we number the carbon atoms from the Omega Carbon which is again the last carbon atom here. And so, with omega carbon atoms, we number the carbon atoms in the opposite way. Now, this omega naming system and numbering system is really used to highlight biologically relevant features and differences, such as biologically relevant double bonds. And so moving forward, we're going to talk about very specific omega fatty acids, uh, specifically the omega three fatty acids. And so we'll talk about those in our next lesson video, so I'll see you guys there.
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Omega-3 Fatty Acids

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in this video, we're going to talk specifically about omega three fatty acids. And so omega three fatty acids, as the name implies, are just fatty acids with a double bond located exactly three carbon atoms away from the omega carbon. And so if we take a look at our example down below, we're showing you three classic examples of omega three fatty acids and these are alpha linoleic, which is right over here, E cosa pantano or E. P A. Right here in the middle, and Dakota or D H. A. Over here on the far right and notice that all three of these omega three fatty acids all have a double bond that is located exactly three carbons away from the omega carbon, which again, is the last carbon furthest from the car box. Silic acid carbon. And so what's important to note about these omega three fatty acids is that they are actually essential in the human diet for normal growth. And so the reason that they are essential is because these omega three fatty acids, uh they actually cannot be produced by human cells at a substantial rate. And so for that reason, they're actually essential in the human diet. And these omega three fatty acids have been linked to decreased risk of cardiovascular disease, as well as decreased risk of heart attacks and blood clots. So there's definitely good signs that omega three fatty acids are again essential in the human diet. Now, the omega three fatty acids can be commonly obtained in the diet through multiple sources, but they're very common. And vegetable oils such as corn oil and alpha linoleic A is common in corn oil. Uh they're also very common in cold water fish such as salmon and e. Cosa Penta, noah or E. P. A. Here is um very common in cold water fish. And omega three fatty acids are also common in marine algae, which of course fish are going to live in and sometimes eat. And the omega three fatty acids and marine algae can be passed down the food chain. And so ultimately what you'll notice is the cossacks and over here we've got this marine algae and something that's interesting to note is that these omega fatty acids when they're arranged like this, they actually kind of look like fish themselves. And so we've got these goldfish here, uh that kind of resembles, you can see this shape right here is kind of the same shape that you see right here. So they kind of do look like goldfish a little bit. So hopefully the goldfish can be a little reminder of these omega fatty acids for you guys. Now, the last thing I want to note here is that omega six fatty acids are just gonna be fatty acids with a double bond located exactly six carbon atoms away from the omega carbon. And so whenever you see omega and a number, that number is just telling you how many carbon atoms away that double bond is from the omega carbon. And so really this concludes our introduction to Omega three fatty acids, and we'll be able to get some practice applying the concepts that we've learned in our next couple of practice videos, so I'll see you guys there.
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Problem

Draw the structure of docosahexaenoic acid (22:6Δ4,7,10,13,16,19) and indicate what type of omega fatty acid it is.


a) Omega-3 fatty acid. 

b) Omega-6 fatty acid. 

c) Omega-9 fatty acid.

d) Omega-4 fatty acid.

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Problem

Assuming the standard shorthand naming system is used, which of the following is an omega-3 fatty acid?


a) 20:1Δ14

b) 18:3Δ9,12,15

c) 20:1Δ3,12

d) 18:2Δ9,12

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Problem

Which of the structures below is an example of an omega-3 polyunsaturated fatty acid? 

a) A

b) B

c) C

d) D


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