Are triglycerides polar?

[dmission]

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One of the biology books that I was looking says that triglycerides are polar molecules, but that doesn't make much sense to me. For example, I know oils are mostly triglycerides, and oil (usually called nonpolar?) doesn't mix with the polar water. As far as I know, a triglyceride is just three fatty acid chains connected to a 3-carbon molecule, so it seems like it'd be nonpolar to me -- unless just the oxygens make the whole thing polar?

Would appreciate any clarification, thanks.

 

[Axon hillock]

One of the biology books that I was looking says that triglycerides are polar molecules, but that doesn't make much sense to me. For example, I know oils are mostly triglycerides, and oil (usually called nonpolar?) doesn't mix with the polar water. As far as I know, a triglyceride is just three fatty acid chains connected to a 3-carbon molecule, so it seems like it'd be nonpolar to me -- unless just the oxygens make the whole thing polar?

Would appreciate any clarification, thanks.

Ever see oil float on top of water? Triglycerides are made up of 3 fatty acids and glycerol. The glycerol part with the oxygens are relatively polar. The long carbon chains are nonpolar.

 

[dmission]

Ever see oil float on top of water? Triglycerides are made up of 3 fatty acids and glycerol. The glycerol part with the oxygens are relatively polar. The long carbon chains are nonpolar.

So would you call the molecule as a whole polar then, because of the oxygens in the glycerol?

 

[Axon hillock]

So would you call the molecule as a whole polar then, because of the oxygens in the glycerol?

No, I would say it has a polar head group and a nonpolar tail. Much like a phospholipid. If you have a question on triglycerides just be aware that part of it is polar.

 

[dmission]

No, I would say it has a polar head group and a nonpolar tail. Much like a phospholipid. If you have a question on triglycerides just be aware that part of it is polar.

Thanks. And I guess it'd be the same sort of thing for a fatty acid, with the carboxylic acid end being slightly polar?

 

[Axon hillock]

Thanks. And I guess it'd be the same sort of thing for a fatty acid, with the carboxylic acid end being slightly polar?

Yea, The head group is polar and the long hydrocarbon chain is nonpolar.

Edit: Btw all these molecules are considered amphipathic. Meaning they have both hydrophilic and hydrophobic regions.

 

[dmission]

Thanks, good to know. I have to say though, I'm still a bit confused about why fats (triglycerides) are always called non-polar, even though there is a polar part of the molecule? Just because they're *mostly* nonpolar, perhaps?

 

[salim271]

Thanks, good to know. I have to say though, I'm still a bit confused about why fats (triglycerides) are always called non-polar, even though there is a polar part of the molecule? Just because they're *mostly* nonpolar, perhaps?

I wouldnt worry too much about it. Triglycerides and fatty acids are both amphipathic, triglycerides more so because they have three polar heads. In the most technical sense, they are polar because they have polar groups, but their nonpolar segments are so long, most of the bonding they do is of the nonpolar variety.

 

[Kalamazoo]

Shorter triglycerides are considered more polar. The longer the hydrocarbon tail, the less polar the molecule.

 

[Axon hillock]

Thanks, good to know. I have to say though, I'm still a bit confused about why fats (triglycerides) are always called non-polar, even though there is a polar part of the molecule? Just because they're *mostly* nonpolar, perhaps?

Triglycerides have to be considered "nonpolar" for the most part otherwise they would dissolve in water or blood and you know that doesn't happen. Remember the phrase "like" dissolves "like"

 

[Javali]

One of the biology books that I was looking says that triglycerides are polar molecules, but that doesn't make much sense to me. For example, I know oils are mostly triglycerides, and oil (usually called nonpolar?) doesn't mix with the polar water. As far as I know, a triglyceride is just three fatty acid chains connected to a 3-carbon molecule, so it seems like it'd be nonpolar to me -- unless just the oxygens make the whole thing polar?

Would appreciate any clarification, thanks.

In case of triglycerides,all three OH groups of alcohol are neutralised by fatty acids (polar), hence non polar.unlike ,di and tri gycerides where only 1 or 2 OH are occupied by fatty acids ;making, one or more polar OH group free....