Uploaded by bozemanbiology on 09.11.2012


Hi. It's Mr. Andersen and in this podcast I'm going to talk about polymers.
Polymers are large molecules that are made up of smaller molecule called monomers. And
so even the word polymers can serve as a good example of a polymer. In other words I could
rearrange the letters in polymers to make Mrs. Poley or even a spry mole or even a spying
mushroom. And so basically those letters can be arranged in different ways to make different
words. Likewise, monomers can be arranged in different ways to make different polymers.
And so the large molecule's a polymer but those building blocks are called monomers.
And so where do we see this? Well in biology we could see this lots of places. And so this
right here is a strand of cellulose and cellulose is a polysaccharide which is made of sugar
over and over and over again. Or this right here is a protein. Protein is made up of amino
acids attached over and over and over again. And so we have 26 letters in the alphabet.
And we can make words and we can make paragraphs and even stories. And in life we have 20 amino
acids. And those amino acids can almost make an infinite number of proteins. Or this right
here is deoxyribonucleic acid or DNA and that itself is made up of monomers. Those are called
nucleotides. Essentially we have a phosphate, a sugar and then a nitrogenous base. And so
even that nice leisure suit that your dad may have worn in the 70s is going to be a
polymer. In other words we're reproducing the simple chemical over and over and over
again. And so how do we do that? Well basically we do it in one of two ways. We either build
a polymer and to do that we use what's called a condensation or a dehydration reaction.
Or we break it down. And so let's start with building. And so right here we have two amino
acids. And so amino acids remember are going to be put together to make proteins. And so
you can see on this first amino acid we've got that alpha carbon in the middle, we've
got an amino group on one side, carboxyl group on the other. Likewise with this amino acid,
we've got an amino group of this side, we've got the carboxyl group on this side and then
we have our R groups on either side. And so basically what happens in a condensation or
dehydration reaction, if you look right in the middle, is we're going to remove water.
In other words we have this hydroxyl group here and this hydrogen here and so basically
what happens is we give off that water, you can see why it's called a dehydration reaction.
We're losing water and basically we're forming a bond. We're forming a bond between those
two amino acids. In other words we're making a simple little polypeptide. And this occurs
over and over and over again when we make a massive protein. Well, what's the opposite
of that? We call that hydrolysis. And I always think of hydrolysis means water cutting or
water breaking. And so let's say right here we have a simple disaccharide. This is lactose.
What we can do is we can add water to the system. And we do that, basically what we're
going to do, is we're going to break that disaccharide down into two monosaccharides.
And so you have enzymes in your body that are going to help you break down lactose,
but we still are going to require a water every time we break one of those polymers
apart. And so basically let me give you a quick question. You can try to wrap this one
around your head. TRP Cage or trip cage is going to be one of the smallest amino or excuse
me, smallest proteins that we have in nature. And it's found in the saliva of a Gila monster.
And so how many molecules of water would be required to completely hydrolyze this Gila
monster protein. Now you need to know that there are 20 amino acids that are found in
this very small protein. And so how much water are we going to require to break that up.
So it's a good question. If you want to put your answers down below do so. And so basically
why is this important? Well this is a picture of me when I was little. And my favorite food,
I know this is gross, when I was growing up was the Filet O Fish sandwich from McDonalds.
And so basically when I was eating that Filet O Fish sandwich it was made up of a number
of different polymers, like the polysaccharides in the starch in the bun and the proteins
that are found in the fish in the fillet of fish and so basically when I took this in
and ate it, in digestion I was breaking that back down into its monomers. But then I was
putting those back together again using dehydration reaction to make the proteins that are found
in my hair or my skin or all of the cells in my body. And so you literally are what
you eat thanks to polymers. But again, they wouldn't be formed unless we had the building
blocks and those are called monomers. And I hope this is helpful.