Monomers & Polymers - Online Tutor, Practice Problems & Exam Prep

Monomers are the individual building blocks that link together to form polymers, which are long chains of these monomers. Carbohydrates, proteins, and nucleic acids utilize consistent monomers—monosaccharides, amino acids, and nucleotides, respectively—while lipids do not follow a uniform monomer structure. To build polymers, cells perform dehydration synthesis, forming covalent bonds and releasing water. Conversely, hydrolysis reactions break down polymers into monomers by adding water to cleave these bonds. Understanding these processes is crucial for grasping biomolecular structures and functions.

Monomers & Polymers

In this video we're going to introduce the two terms, monomers and polymers. And so monomers with the mono prefix are going to be single individual building blocks that can be repetitively linked together to form polymers. And so the root mono is a root that actually means 1 or singular, whereas the root poly in polymers is going to mean many, and so polymers are defined as long chains of many monomers that are linked together. Now the monomers, those individual building blocks that are used to build polymers, will actually vary depending on the type of biomolecule polymer that they're building. And so it's important to also note that carbohydrates, proteins, and nucleic acids, they all use consistent monomers to form their polymers. However, lipids are a little bit different because they do not use a consistent monomer to build polymers, and we'll get to talk more about these lipids later in our course. But for now, let's focus on the monomers and the polymers.

So if we take a look at our example image down below, we can focus on the monomers and the polymers. And so actually, I'm going to direct you to this image over here on the right-hand side, which shows you these individual separate building blocks over here. And because these are single individual building blocks that are separate from one another, we refer to these as monomers. And then of course, if we were to link all of these monomers together into a long chain of many monomers linked, then we have ourselves a polymer. So this whole thing is a polymer and these individual pieces that we see over here are the monomers.

Now as we mentioned up above in our text, monomers are going to vary depending on the type of biomolecule polymer, and really it's only the carbohydrates, proteins, and nucleic acids that use consistent monomers, so those are the ones that we're going to focus on over here in this key. And the lipids, they don't use consistent monomers, so we'll talk about the lipids later. But if we take a look at this key over here on the left-hand side, notice that for carbohydrates all of these little gray monomer building blocks that we see over here are really going to be monosaccharides. And moving forward in our course, we're going to represent those building blocks, those monosaccharides as these bluish hexagons. Now for proteins on the other hand, these gray building blocks that we see over here, these monomers would actually be amino acids, and those amino acids moving forward in our course, we're going to represent them as these circles. And then for nucleic acids, the monomers, these pieces that we see here are really going to be nucleotides, which moving forward in our course we are going to represent with shapes that look like this. And so the real main point here is that these monomers they're going to vary. What these building blocks are, they’ll vary depending on the type of biomolecule polymer that they're building, whether they're building carbohydrates, proteins, or nucleic acids. And so once again, we'll get to talk more about monomers and polymers moving forward in our course and this is just the introduction. So I'll see you all in our next video.

Building & Breaking-Down Polymers

In this video, we're going to talk about building and breaking down polymers. And so if a cell wants to build a polymer, then it needs to perform a dehydration synthesis reaction. And so as its name implies with the synthesis part here, dehydration synthesis reactions are going to form covalent bonds to link individual separate monomers together and begin to build a polymer. And so you can see that the synthesis here is all about forming and building a polymer. Now, on the other hand, if a cell wants to break down a polymer into its small individual pieces, then it needs to perform a hydrolysis reaction. And so dehydration synthesis and hydrolysis reactions are opposites of one another. And so hydrolysis has the root lysis in it, which is all about cleaving and breaking things down. And so hydrolysis is going to cleave covalent bonds between the monomers and release the monomers as separate pieces by breaking down the polymer. And so once again, dehydration synthesis is all about building a polymer, whereas hydrolysis is all about cleaving or breaking down the polymer. So let's take a look at our image down below to get a better understanding of the formation and breakdown of polymers. Now what's important to note is that on the left-hand side of our image, we have two separate monomers, one over here and one over here, And on the right-hand side of our image, notice that those monomers are now joined together covalently, and so it's starting to build a polymer over here on the right-hand side. And so, of course, if we want to join together two separate monomers and begin to build a polymer, we're going to need a dehydration synthesis reaction. And so in the dehydration synthesis reaction, the hydroxyl group, the OH group of one monomer, is going to interact with a hydrogen on another monomer, and so OH and H are going to release a water molecule, and so you can see the blue O here is coming from this O, and the yellow H here is coming from this hydrogen. And so when water is released, as we see here, that is dehydrating the molecule. The molecules are losing a water molecule, so the water molecules are being dehydrated. And in the process, it's synthesizing something, it is building a polymer and so that's how the monomers are joined together covalently here as we can see. Now if we wanted if the cell wanted to do the opposite and break down this mon or this polymer into its separate individual monomers, then it's gonna need the backwards reaction to release, those two monomers. And recall that is called hydrolysis. And so once again the lysis part is all about cleaving and breaking things down. And so this bond here can be cleaved or broken by using water and that's what the hydro prefix is for in front of hydrolysis. It's saying water is needed in order to, cleave or break it down. And so notice that a water molecule is going to be added to the process and it's going to split the molecule in half. And so once again, the biggest takeaway here is that if a cell needs to build a polymer, it will perform a dehydration synthesis reaction. And if the cell needs to break down a polymer, then it's going to perform a hydrolysis reaction. And so that concludes our introduction to this concept and we'll be able to get practice applying this throughout our course as we move forward. So I'll see you all in our next video.

Which of the following statements concerning dehydration reactions and hydrolysis is correct?

• A. Dehydration reactions allow solutions to evaporate; hydrolysis reactions dissolve solutes.
• B. Dehydration reactions and hydrolysis reactions assemble polymers from monomers.
• C. Hydrolysis reactions create polymers from monomers; and dehydration reactions create monomers from polymers.
• D. Dehydration reactions create polymers from monomers; hydrolysis reactions break down polymers.

_________ bonds are formed between monomers to form a polymer.

• A. Ionic bonds.
• B. Covalent bonds.
• C. Hydrogen bonds.
• D. Hydrophobic bonds.
• E. Nuclear bonds.