Why is the melting point of an unsaturated fatty acids lower than saturated with the same no. of Carbons?

Question

-How does the no. of carbon atoms affect melting point??

-Write the general formula of fats and oils? How does one differ from the other in terms of structure?

-Is it true that fats from animal sources are saturated while those from plant sources are unsaturated? Which is better as food source? Discuss the claim that virgin coconut oil has health benefits. How is margarine made? Is it a better substitute for butter?

Answer 1

Unsaturated fats are already liquids at room temperature. Because of the double bonds between the carbons of the fatty acid chains the molecule is "unstacked", and therefore forms "random" arrangement, leading it to be liquid at room temperature (or body temperature). This is why eating unsatuated fats is better for you healthwise.

Saturated fats (triglycerides) are composed of one glycerol molecule (C3H8O3) and three fatty acid chains. A fatty acid chain is composed of a carboxylic acid group (C=OOH) and a long chain of singly bonded carbons with hydrogens completing the four bonds of the carbons.

An unsaturated fat is just like the above, except it has one or more double bonds between the carbons of the fatty acid chain.

Animal fats are saturated; plant fats are unsaturated.

Margarine is made from unsaturated fats that have been artifically "hydrogenated" in order for them to have a "solid" texture to put into sticks. If you let them set on the counter and come to room temperature they will "melt". Butter, a saturated fat made from animal milk fat, will not melt when left setting out on the counter. It will only get soft.

Margarine is a better health food than butter because it stays liquid in the blood stream and does not clog your arteries the way butter can.

I have no idea about your "virgin"coconut oil.

I would think that the more carbon atoms you have the higher the melting point as the more bonds you would have to break.

BIOCHEMISTRY TEACHER

Answer 2

Yes, all that the above person posted is right except they forgot to mention that:
w/ double bonds in the molecle, the unsaturated fatty acids thus have kinks in the molecule. This naturally causes it to be broken up easily despite having the strong double bonds (and that is why it is usually fluid at room t)
Oh, and if anything, straight-chain C's does not make it stronger, it makes it weaker b/c double bonds are more durable so in that sense, it seemingly does not make sense that unsaturated would have a lower melting pt, but when you consider it's physical structure and the kinks in the molecule, it makes sense.

Answer 3

First of all the blood brain barrier blocks most of the fatty acids,except the essential ones because they are needed for the growth and development of the neuroglial cells and the neurons also. Secondly, Fats have respiratory quotient less than glucose i.e. unity. hence fats liberate energy at a much slower rate than glucose and as brain works very fast thus it requires energy readily. Hope u get it thank u.