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Voice 1: Triglycerides and Fatty Acids. My name is Reyna and today we are going to teach
fatty acids and triglycerides. Four our real life example we choose olive oil. Today we
are going to start by teaching the concept of Fatty Acids so you can further understand
triglycerides. Voice 1: What are Fatty Acids? Well let us
further explain. Fatty Acids the Element of Fatty Acid structure is quite simple. There
are two features first there is a long hydrocarbon chain. The length of the chain can be from
4 to 30 carbons, but having 12 -- 24 carbons is more common. The chain is typically linear
and contains an even number of carbons. Secondly it contains a carboxylic acid group. Here
is what a fatty acid structure would look like. It contains a carboxyl group and a hydrocarbon
chain. Voice 1: Fatty acids are different from one
another in the number of carbon atoms that they contain and in the number of carbon-carbon
double bonds. Saturated fatty acids contain a single bond. Monounsaturated fatty acids
have one double bond and polyunsaturated fatty acids have two or more double bonds.
Voice 1: Let us further explain in a demonstration. Voice 2: I want to talk about triglycerides
in this video, but for understanding better triglyceride structure it's better to know
the structure of fatty acid first. I draw here the structure of fatty acid. As you see
it contains carboxylic Acid head, which is hydrophilic because of the negative formal
charge and also its hydrophobic hydrocarbon long tail. Commonly it's between 12 to 20
carbons. It makes the fatty acid amphipathic compound. Because it has a formal charge,
hydrophilic and it has a long hydrophobic hydrocarbon tail. I drew here all of the carbon-
carbon bonds single bonds. It makes the fatty acid saturated fatty acid, if I change one
of these bonds to double bond its monounsaturated fatty acid. Mono means one, it means we just
have one double bond in the structure of the hydrocarbon tails. If we have two or more
than two in the hydrocarbon tail we have polyunsaturated fatty acids, it means we have two or more
than two double bonds in the hydrocarbon tails. Voice 1: now let's talk about the interactions
between them. Interactions between fatty acids. Saturated fatty acid hydrocarbon tails interact
through relatively strong London forces. They have high melting points and high boiling
points. Cis double bonds in unsaturated fatty acids interact less efficiently because of
their shape resulting in weaker London forces. Therefore having lower melting points and
lower boiling points. Here is a demonstration to help you understand the concept.
Voice 2: in the second video I want to talk about intermolecular forces between fatty
acids, which is London forces. Here I drew the saturated fatty acids as you see. I drew
just single bond between carbon carbons. In saturated fatty acid because of the single
bond and because of the shape. The molecule is like a big floppy molecule and the molecule
can get closer together. They have free rotation so they have strong strong London forces and
they have higher melting point and higher boiling point. In the room temperature, it
makes them mostly in the solid form. In unsaturated fatty acid because of the double bond and
because of the shape they can get closer together and they don't have free rotation. So they
have weaker London forces and they have weaker intermolecular forces. They have lower melting
point and lower boiling point. Mostly in the room temperature we can see them in liquid
form. Its because intermolecular forces are so weak.
Voice 1: Now that you learned about fatty acids let's talk about triglycerides. Triglycerides,
a triglyceride is an ester derived from glycerol and three fatty acids.
Voice 2: in this video I am going to talk about triglycerides. Vegetables oils and fatty
acids here is one saturated fatty acid and two unsaturated fatty acids. To make triglycerole
you just delete all the OH bonds from fatty acids and all H bonds from glycerol. And I
create a bond between fatty acids and glycerol to make triglyceride. As you see here is one
saturated fatty acid and two unsaturated fatty acids. If we have more saturated fatty acid
than unsaturated fatty acid, we have saturated fat. Or if we have more unsaturated fatty
acid than saturated fatty acid we have unsaturated fatty acid.
Voice 1: Lets continue talking about triglycerides. Lard and beef fat are solid triglycerides
because they contain more saturated fatty acid residue than unsaturated residue and
have melting points above room temperature. They contain three saturated fatty acids with
glycerol or two saturated fatty acids with one unsaturated fatty acids. On the other
hand vegetable oils are liquid triglycerides because they contain more unsaturated fatty
acids residue than saturated residue and have melting points below room temperature. They
can contain three unsaturated fatty acids with glycerol or they can contain one saturated
fatty acids with two unsaturated fatty acid with glycerol.
Voice 1: an example of liquid triglyceride would be olive oil. Here is how the olive
oil structure would look like. Voice 2: at the end I want to show you an
example of a triglyceride. I draw here three oleic acid, which is three unsaturated fat
and I draw here glycerol. It's the common form of olive oil. First I am gonna delete
all of the OH from oleic acid and all of the H from glycerol and make ester bond to make
to make the triglyceride of olive oil. Also we see olive oil as liquid form. As I told
you about unsaturated fat because of their shape and free rotation they can rotate so
good. They have weaker London forces and they are liquid in room temperature.
Voice 1: by watching this video you should be able to know what a triglyceride structure
is and what a fatty acid structure looks like as well. I hope that you learned something
from this video and thanks for watching. Voice 1: Reyna and Ronak video project for
chem 108 for Dr. Zoval.