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Monomers and Polymers

A polymer is a large molecule composed of many repeated subunits. The term was coined in 1833 by Jöns Jacob Berzelius, though the first synthetic polymer was not produced until 1855. Polymers are typically extended chains of many repeated subunits. The length of a polymer is usually many thousands of monomer units. Most natural polymers are biopolymers (e.g. proteins, DNA, and RNA), but many common synthetic polymers are thermosets (e.g. polystyrene and polyvinyl chloride) or thermoplastics (e.g. polyethylene, polypropylene, and polyvinyl alcohol). Polymers are also often referred to as plastics, but that term is ambiguous and sometimes misused.


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Video Transcript

in this video will discuss monomers and polymers. So monomers are going to be these sub units that will make up larger chain molecules called polymers, and specifically when we are referring to carbohydrates, proteins and nucleic acids in biological systems. Then we are referring to what are called macro molecules because these molecules will be macro or very large. And these are just going to be polymers in biology. So, for example, DNA is going to be a macro molecule and so will proteins, and so will carbohydrates such as cellulose. So we know about macro molecules. How are they made and how are they disassembled? Well, a monomer, as we have said before, is going to be a small molecule. Or we could actually say small molecular sub unit of a larger change, whereas our polymer is going to be the chain itself. So it will be a long, large molecule consisting of smaller and somewhat identical sub units. Now, they might not be exactly the same, but they will definitely be similar. So actually that would be a better word to use in there similar sub units. So how do we make these polymers? Well, it will all come down to what is called a condensation reaction. So a compensation reaction will basically linked to monomers together. So let's say we have one monomer right here, and we have a second right here. And actually we can say that this is going to be part of a larger polymer chain. So the way that these monomers are arranged is that each one will have. So if we're just taking a look at our monitor by itself, each one is going to have a hydrogen on one end and a hydroxy or O H group on the other end. And if we bring these two together, or bring them really close to one another the way that we would attach it, do you see a mechanism by which we could get attach it? That's right. It would be via these two. Adams would be the hydrogen and the hydroxy group, so the hydrogen right here would combine with this hydroxy group right here and leave as a water molecule or H two out because there's one H, there's a second H and there's our oxygen. So we have formed H 12, and now we have produced. In addition, to our polymer. Actually, there we go. And then this would be an O. H right here. As you can see, we have taken this hydrogen combined it with this hydroxy group they have left in the form of water. And we have now added this monomer right here to our polymer. So we have elongated our polymer. So conversation reactions are responsible for polymer synthesis and water is a byproduct. Thus condensation with water leaving our system. The opposite would be a dehydration reaction or a hydrologist reaction. So that will simply be a reaction where we're going in the opposite direction. So let's draw that out. If we're starting with the same Palmer as here, so we'll just copy it down. We'll have our hydroxy attached to four monomers in sequence with hydrogen on the end. So if we start with this kind of polymer, if we try to insert water in between, let's say these two mon American units. If we add water into their now, we can produce a shorter polymer or cut this polymer into two pieces, right? Because now we'll have, of course, an O. H here combined with thes two units. And we'd get our hydrogen on this end. So that's one hydrogen from the water. And now we'd have the rest of our water molecules. So ohh, right here, attached to two more Monta Merrick sub units. So let's count how Maney monitors We had 123 for in the original in the same thing 12 three, and four in the product. So, as you can see, we have cut our polymer in half using water. So a hydrologist reaction will lead to polymer degradation or shortening. Because if we were to do this at the end, we would be able to basically cut the final monomer off and make a shorter polymer with just this one monomer by itself. Or we can just use hydraulics is in order to cut our polymer in half. So the question now is which reaction will occur. And as we know, hydraulics, ISS reactions are going to be energetically favorable. So this formation of polymers or condensation reactions is going to be energetically unfavorable. Whereas if we are to look at hydraulics reactions, we see that these are going to be energetically favorable, meaning that they can occur spontaneously. So here we have discussed polymers and monomers and how the two will be made or disassembled. And the last thing that we want to do is just give you an example off a polymer that we confined in biological systems. And that would be, I think the most common one that would come to mind would be a poly sacha ride. So of course, these were going to be some examples. So Polly Sacha rides would basically be these long chains off glucose molecules. So, for example, a cellulose would be a poly sack arrived. But also DNA is going to be polymer as well and in DNA, the monomer. So here we can start differentiating between the monomer, monomer and polymer. The monomer and DNA is going to be the nucleotide base, which will all link up together eventually to form our polymer, which is the whole DNA molecule. So the DNA molecule is going to be the polymer, whereas our nucleotide base is going to be the Mon America unit