hey everybody it's your ap bio teacher mr poser we are continuing our first unit on the chemistry of life with topic 1.4 properties of biological macromolecules um in our last video we discussed which i actually got this page from in our last video we discussed how monomers become polymers how polymers can become monomers through two processes called dehydration synthesis and hydrolysis so if you recall from last video monomers are smaller molecules or building blocks of these larger molecules called macromolecules and when you link them all together through a process called dehydration synthesis you get monomers mono meaning one into polymers and poly means many so polymers are like uh polysaccharides which are complex carbohydrates proteins um complex lipids and of course dna and rna those are all polymers and they're made up of smaller molecules called monomers so for this video in the next video we will break down the properties and the structure and function of these four classes of biological macromolecules carbohydrates proteins lipids and nucleic acids um but in this video we're going to discuss the properties as they pertain to the monomers of each of these types of molecules so this video will be focused on the monomers and then the next video 1.5 will be focused on the polymers and more destruction and function of the polymers themselves the big molecules all right but we're focusing on the monomers today uh so obviously you don't have to write this down again because you did already so let's get started um so as i said the monomers that make up macromolecules determine the properties of the macromolecule so what we're going to be discussing in this video today are mostly the monomers so the monomers of carbohydrates as i put up here let me just move my face uh the monomers of carbohydrates are called monosaccharides the monomers of proteins are called amino acids the monomers of some lipids some types of lipids are called fatty acids and the monomers of nucleic acids are called nucleotides and we're going to be discussing each one of these four and some of their biochemical properties uh today all right so let's get started we're going to start with discussing monosaccharides and carbohydrates and the link between those two alright so complex carbohydrates are made up of monomers called monosaccharides a complex carbohydrate is also known as a polysaccharide so monomer monosaccharide polymer polysaccharide that's why we start with this one because it's the easiest um so monosaccharides all typically end with os as a suffix um and they are made up of three to six carbons in a ring um along with some o and h atoms so oxygen and hydrogen atoms so take a look our main it's not that big here but our main monosaccharide the most famous one and the most important one biologically is glucose and there's a picture of it glucose is a ring of six carbons and attached to it it has these h's and ohs and the proper name for these h's and ohs are hydronyl groups which is the h and the hydroxyl group which is the oh but generally speaking every monosaccharide has three to six carbons with these h's and ohs attached to it glucose is going to be the most important because it serves as the starting point for cellular respiration and a bunch of other metabolic processes so cellular respiration which is a topic we'll discuss at length in uh unit 3 is how your mitochondria and your cells are able to produce atp the polar health of the phil so there's glucose um some other examples of monosaccharides i've pictured here are fructose and galactose as you can see fructose is a five carbon monosaccharide and galactose is a six carbon monosaccharide with a different configuration of h's and ohs than glucose um so fructose you may have heard of it before in high fructose corn syrup so glucose fructose and galactose they all tend to be very sweet sugars sweet to your tongue so yeah these are a major source of cellular energy fructose and glucose are really really important for a process called glycolysis which is a precursor for cellular respiration very very important so if we take monosaccharides excuse me monosaccharides and link them together through a covalent bond bond called a glycosidic linkage man i can't talk uh we get a disaccharide die meaning two so disaccharides are made of two monosaccharides joined by a glycosidic linkage and yes i will ask you uh to know what a glycosidic linkage is um so to take a look at these examples that i've pointed to here we have sucrose which is also known as just table sugar um and lactose which is the main sugar found in milk so if you take a look at sucrose over here we have two monosaccharides linked together with this covalent bond right here and those are monosaccharides are glucose and fructose okay so we link those two together we get sucrose um and lactose down here which is you know you might be lactose intolerant because your body might not be able to digest this this sugar which is made up of a galactose and a glucose linked together so those are disaccharides monosaccharides and disaccharides are both considered simple sugars while all carbohydrates another word for carbohydrates is sugars glucose fructose sucrose those are all considered simple sugars because they're either made up of one carbon ring or only two carbon rings all right um so if we were to take a lot of these monosaccharides or disaccharides and link them together in a really long chain that could be hundreds or thousands of links long that would be called a polysaccharide and that's what we'll get into in the next video when we discuss carbohydrates okay so continuing on to proteins proteins are made up of monomers called amino acids um and a bunch of amino acids in a chain thousands of amino acids or hundreds of amino acids in a chain those are what make up protein so we'll discuss amino acids at length today um the order of amino acids in a chain which is a protein determines its properties um what i have pictured here is what we call a generalized amino acid so there are 20 different amino acids but all of the amino acids have three similar similarities between them all of them have this group over here an nh2 and all of them have a cooh and all of them have an r and so hold on a sec r is not an element it's not an atom there's no element that's well there's radon but the symbol symbol is r a so what the heck is r let's discuss it um all amino acids all of them doesn't matter if you're glycine or tryptophan or lysine um they all have what we call an amino group over here or an amino end and they all have a carboxyl end or a carboxyl group um so i've highlighted each of these and have corresponded their colors so this is an amino group over here the nh2 and carboxyl group cooh so each of these amino acids if we were to put another amino acid there the carboxyl group would be linked to the amino group and each of these links are called peptide bonds okay so imagine another amino acid linked over here and another one linked over here kind of in the same configuration those so peptide bonds are what holds a protein together and links the individual components of a protein the amino acids so the things that make amino acids different though despite the fact that they all have an amino group in a carboxyl group are the r groups and the reason why we have r over here is because r is kind of variable for lots of different um lots of different structures that can be attached to the rest of the amino acid here so that's why it's also called a side chain you might hear both of these terms when discussing amino acids an r group or a side chain and the 20 different amino acids have 20 different side chains they all have this but they all have different r groups or side chains and those side chains have different properties that affect the structure and thus the properties of the protein and the function okay so let's discuss these r groups a little bit um here is a table showing all 20 different amino acids and they're grouped by the properties of the side chain so over here we have electrically charged side chains so um ones that have a positive or negative charge we have polar but uncharged side chains like serine and threonine over here we have some special cases that don't exactly fall into one of these other categories and we have non-polar or also known as hydrophobic side chains um amino acids over here okay so say tryptophan over here it has a nonpolar side chain which makes it hydrophobic hydrophobic meaning water fearing so hopefully we discussed that a little bit in our 1.1 topic all right so depending on which amino acids make up the chain and make up the protein that will determine the structure and function of the protein and thus the shape of the protein as well because interactions between these side chains determines a lot about the protein structure that's a topic we'll get into a lot in our next topic 1.5 all right um so those are amino acids let's discuss lipids now so lipids are a diverse group of nonpolar molecules and the thing that unites lipids together is that they're all hydrophobic um and they're all nonpolar so they do not interact with water so generally lipids are categorized by fats phospholipids and steroids even though they're you know they're pretty complex they don't fall into a nice category like say proteins or lipids or exceeding proteins or carbohydrates um all right so the kinds of lipids that we're going to be talking about in this video and a little bit in the next video are called fats and phospholipids um phos fats are also known as triglycerides and i'll show you why in just a second but both triglycerides and phospholipids have these structures called fatty acids which are basically just long hydrocarbon chains that either have a bunch of single bonds or they have some double bonds as well so we'll talk about the properties of those triglycerides are called triglycerides triamine 3 because a triglyceride is made up of a glycerol molecule and it has three fatty acids so triglycerides are you know they're generally known as fats and when you get the fats so when doctors measure the amount of fat you have in your blood they're actually measuring the your blood triglycerides and then phospholipids are made up of a polar group a polar head that has a phosphate group within it and then two fatty acid tails are two fatty acid chains all right so both of these have fatty acids let's talk about these fatty acids so i'm going back to triglycerides for a second because that's what i have a picture of over here triglycerides or fats can be grouped into unsaturated or saturated based on the structure of the fatty acids right so you might have seen these on a nutrition label before unsaturated fatty acids tend to be the good ones because they're liquid at room temperature say like your oils and stuff you find in fish and avocados nuts that kind of stuff and then saturated fatty acids are or saturated fats um so these are triglycerides that have saturated fatty acids um those are like your lards butters um any any kind of fat that's solid at room temperature and these are considered usually bad um and i'll tell you about why in just a second here um so unsaturated fatty acids which i've color coded in orange here have at least one double bond in their hydrocarbon chain um so here's a unsaturated fatty acid um it has check it out i put a little star here next to the double bond and take a look at the shape of this unsaturated fatty acid as opposed to saturated fatty acids it has a kind of a kink or a bend in it um and that has to do with the fact that double bonds tend to be more rigid than single bonds so um unsaturated fatty acids have like kind of a kink in the chain and have a different shape and that lends itself to not be able to pack together as well as saturated fatty acids thus these fats with an unsaturated fatty acid tend to be liquid at room temperature while saturated fatty acids they only have single bonds in between each one of the carbons so saturated means they're actually like covered by by hydrogen atoms see um there's there's some carbons here that don't have you know two hydrogen atoms attached to them but all of these have two at least two hydrogen atoms attached to them that's why they're called saturated um so saturated fatty acids only have single bonds um and fats that have have only saturated fatty acids are usually solid at room temperature and the reason why that is um is because these are more fluid they don't have this bend um and these are able to pack closely together um at lower temperature or even at higher temperatures so that they are tend to be solid at room temperature and the reason why they're considered bad because if it's something solid in your bloodstream you've got a lot of saturate saturated fatty acid in your bloodstream those can cause clots and clots can lead to things like heart attacks and strokes and just overall raise your high raised blood pressure and cause hypertension okay so a little sidebar there about nutrition but we're gonna wrap this up here here we go come on there we go wow i don't know why that took so long uh all right so wrap this up with nucleic acids and nucleotides nucleic acids so dna and rna are chains of monomers called nucleotides um so kind of like proteins amino acids um are just you know they're the links of a chain which is a protein nucleotides are the lengths of a chain in a nucleic acid like dna or rna and all of our nucleotides have a kind of similar to amino acids again all nucleotides whether you're a t c g or u have a five carbon ring like this kind of like a carbohydrate um have a phosphate group up here so it's a phosphorus atom attached to two three oxygens and an o h group or a hydroxyl group and a nitrogen base which is variable but it has nitrogen in it okay so all of these have these two properties but what makes them different what makes nucleotides different on this dependence on the base here so check it out we have five different nucleotides and those are a t c or g um and those are different by their only by their nitrogenous base um so check it out this picture over here this um this nucleotide is adenine so if you look closely here we have this five carbon ring as we discussed before it has a phosphate group and it has a nitrogenous base over here over as that's a as opposed to i believe this is cytosine yes i believe that cytosine it has a slightly different nitrogenous base attached to it while still having the five carbon ring and the phosphate okay um so what separates out dna from rna there's actually several different things that separate those out but one of them has to do with the nucleotides that make them up dna has a five carbon sugar called deoxyribose and again that oh suffix suggests that you know part of a nucleotide is actually a carbohydrate and rna's five carbon sugar is called ribose and there's a key difference between them so for example right here on this carbon in the uh five carbon ring the the sugar there's an o h here but in dna there's not okay so dna is that called deoxyribose because it doesn't have this extra oxygen attached to what we call the two prime carbon and rna does okay so that is going to be one of the differences between dna and rna that we're going to talk about in topic 1.6 it's just kind of a preview for you there all right that'll be it for this video for 1.4 we're going to get into 1.5 next time and discuss the macro molecules themselves the structure and function all right see you later let me know if you have any questions