in this video we'll be discussing carbohydrates and this is from b1.1 on carbohydrates and lipids this is all part of the core or standard level material as we begin our discussions on biological molecules we're going to notice that these are all carbon based molecules and carbon is a great molecule for all of these biological molecules because it's really good at forming four stable Cove valent bonds now when we say calent Bond what we mean is a bond created by the sharing of electrons between two atoms okay so carbon can form four of those um coal bonds and they are extremely stable carbon can form bonds with itself or with a variety of other elements and that makes it really versatile for creating stable and complex uh structures and molecules and here we have a few examples that you'll be getting quite familiar with um this is a saturated fatty acid and you don't have to know that just yet um but it's important to note here that this carbon based molecule is in like a chain like structure we're going to see that pop up several times as well as carbon rings so we'll be looking at rings in terms of different monosaccharides or sugars um and different types of lipids both of these are based on carbon so let's take a look at how we get some of these complex structures we're going to producing things called macro molecules so this prefix macro means big so I'm going to create big macro molecules by taking smaller units called monomers and linking them together to form a polymer so monomers would be like these small individual units and when you form a bond between them what you're going to get is a much larger molecule and that's called a polymer now the way that that happens is through something called a condensation reaction and condensation reactions are going to involve the removal of water and when you do that it forms a bond between those two molecules and we can see that right here so again we're going to remove a water molecule which is H2O where is that coming from well H2 two hydrogens and one oxygen that's where I'm getting that water molecule and that's going to leave this oxygen left over to be shared by this carbon and this carbon right over here and so we get a bond here now if it is a bond between two monosaccharides more on those later but two simple sugars we call that a glycosidic bond so again this prefix glyco meaning sugar this is just a special type of bond that I get when I perform a condensation reaction between these two sugars leaving them bonded together now mono means one so monosaccharide is a simple sugar a disaccharide die means two a disaccharide is two monosaccharides bonded together so a great example here is moltos Mose is made of two glucose molecules bonded together poly means many saccharide meaning sugar so this is many sugar molecules many monosaccharides linked together and a great example here is a molecule called Amal optin it's one of the forms of starch and Amal optin just so happens to be made of monomers of glucose glucose is a six carbon sugar and those carbons can actually be numbered there's actually an oxygen in this structure right here so to number the carbons we number them this way 1 2 3 4 five and the six carbon is actually up here we generally don't draw that in the ring structure now I can form a bond between the first and the fourth carbon of adjacent glucose molecules and that's going to give me something called a one four linkage one referring to the number one carbon here and four referring to the number four Carbon on the other glucose molecule and when I do that that's going to result in these very like linear portions of a molecule if I have a bond between the first and the sixth carbon of adjacent glucose molecule so something like this and don't forget this is actually attached to this carbon over here that's going to give me a 1 six linkage again between the first carbon of one and the sixth carbon of a different molecule and that results in branching so when we see branches in a molecule especially something like Amal optin we should be thinking about the these one six linkages now regardless of which linkage you're forming they're all formed by these condensation reactions just between different carbons and we're going to be making different macro molecules with different versions sometimes called isomers of glucose and we'll see two here um that are going to be important to us one is called alpha glucose and the other is called beta glucose now what you'll notice about these two is they look very similar but in alpha glucose we have this arrangement of the hydroxy group and the hydrogen connected to that number one carbon and in beta glucose we're going to have a different Arrangement here so again on the first carbon this hydrogen and this hydroxy group are switched so it's important to remember that these molecules are threedimensional and so it's a bit difficult ult to represent that here in two Dimensions but the actual Arrangement or um of these different groups here is very important and gives these glucose molecules some slightly different properties now when we were talking about how to put molecules together we were mentioning condensation reactions well the opposite can also be done so again condensation reactions removing water to form a bond if I do the opposite so if I go the other way around and I add in water that's going to help split apart a molecule and that's something called hydrolysis so this word Hydro meaning water Lis meaning to break I'm literally adding in water to break apart two molecules and that's a very interesting and very important part of what we call digestion now digestion doesn't just happen in your your body it's something that happens to molecules it's the chemical breakdown of larger molecules into smaller molecules so not necessarily chewing your food but the chemical breakdown meaning I'm taking apart these larger molecules to make smaller pieces and that will always involve hydris reactions so we talked about disaccharides which is two monosaccharides hooked together and polysaccharides which is many monosaccharides put together but what is a monosaccharide well this prefix mono again means one and this means just one simple sugar and there are a few simple sugars that you should know so some of them are what we call trios sugars Tri meaning three those are three carbon sugars pentos sugars so pentam meaning five these are five carbon sugars that's going to be something like ribo or deoxy ribos and then we have hexos sugars and hex means six so these are six carbon sugars five carbon sugars and six carbon sugars are going to be in a ring form and they're going to also include an oxygen atom so we looked at Alpha and beta glucose just a little while ago there are one two three four five six carbons but not all six form the ring structure five of them are in the ring structure and incorporated into that ring is the oxygen atom there are lots of important sugars that you should know about or monosaccharides that you should know about but if I had to pick one that was the most important I would definitely say glucose we'll be talking about this one in a lot of different topics so glucose C6 h126 you should know that um it is a polar molecule and so therefore it's going to be soluble in water which means it can be transported in our blood plasma and can do a whole lot of other things it's relatively small um and it's a very stable compound even when it's dissolved in water and what we're going to talk a lot about in future topics is that it yields a lot of energy when it is oxidized so when this is kind of taken apart bit by bit a lot of energy can be released from that molecule with big implications for things like cell respiration there are lots of poly saccharides many monosaccharides bonded together um with very important properties for living things we're going to be focusing on just a small number of them okay and so we'll talk about the similarities and differences here now all of these polysaccharides are not soluble and so that has big implications for things like transport and osmolarity if you've already studied that and they have no fixed size which means that we can add a lot of monosaccharides together to make make a huge molecule or it can be a little bit smaller they're not exactly a fixed size or a fixed number of glucose molecules they do have slightly different functions so we have a polysaccharide called cellulose and that is going to be for structural support So mainly in those like plant cell walls is how we'll be talking about cellulose and then in terms of energy storage glycogen is the energy storage molecule in animals and starch is the energy storage molecule in Plants now what we'll notice is that starch has two different forms one called amalo that's got those 14 linkages and one called Amal opcin that's got those 1 14 and one six linkages um but both of them function as an energy storage molecule so we'll kind of break that down here right okay so energy storage molecule imp plants they are both made out of monomers of alpha glucose so both amalo and Amal optin again what we're going to notice is a different shape due to those different linkages so amalo only the 14 glycidic Bond so that's going to be linear and we say linear it's actually really going to form kind of like this linear spiral shape but it's still linear it's still in a line and this Amal optin is going to have one4 linkages so it's going to form this spiral shape but in addition to that it's also going to have one six linkages so we're going to get these branches and that will look a little something like this U maybe a bit better than my drawings um you should be able to recognize amalo and amalo pectin you should be able to remember that they are both forms of starch and it's a good idea to have um a firm grasp on how those different bonds result in those different structures theme V is all about Form and Function and so that will become a very important concept throughout this topic glycogen is a very similar molecule to amalo or really amalo pectin it's a very similar molecule structurally speaking it's made out of alpha glucose and it's got both 14 and six linkages but it's just got a lot of one six linkages so much more than we would find in Amal optin and that's going to result in a highly branched molecule but again a very similar um structure and function this is an energy storage molecule but not in plants like starch but rather animals and now let's go back and talk about that structural polysaccharide called cellulose so cellulose again doesn't have a function in energy storage and that's kind of tough to remember because it is made of glucose and a lot of people associate glucose with energy but glucose in its beta glucose form and in these one 14 glycosidic bonds doesn't form a molecule that humans can use for energy rather it's a structural component of the plant cell wall so cellulose isn't for energy it's a structural component um and it forms these very straight chains again we should be thinking straight or linear when we see one for glycosidic bonds so this is one molecule of cellulose so again you can see that they form very straight chains because of the arrangement of these hydroxy groups in that glucose molecule it can actually form hydrogen bonds with adjacent chains so remember glucose is a polar molecule and polar molecules are going to have partial charges and when um those opposite partial charges are near each other they can form a hydrogen bond and so we'll have lots of hydrogen bonds that link several of these linear chains together and that makes cellulose very strong okay so again when we think about Form and Function we really need this to be strong if it's going to be a structural component of those plant cell balls and the last carbohydrate that we'll talk about in this video is something called a glycoprotein now this word glyco refers to Sugar so lucky for us it is exactly what it sounds like it is a protein with a sugar or carbohy hydrate molecule attached to it and we're going to see that right here okay so this is my glycoprotein and again it's made up of two components so we've got the protein part down here and then this carbohydrate chain so maybe I'll highlight that in blue here um right up in this region and this is always going to face outwards so this in here would be like the inside of the cell this would be the outs side of the cell and that's very important because this carbohydrate chain is used for recognition each cell is going to have a unique pattern of monosaccharides sticking out here and so we can think of that as being kind of like cellular name tags a way for cells to recognize um each other or maybe recognize things that don't belong there um and that is a very important function of these glycoproteins and we're going to see that play out in a very important example here um of blood type so there are four blood types in humans we have type A type B type AB and O and these different blood types um can be recognized by these different antigens that are on the outside so this is a new word for some of you antigen is a recognition feature on the outside of a cell or a virus um and in this case it is going to be one of those glycoproteins um and there are four sorry three different types of antigens a b and O of course type A B is a blood type that has both type A and type B antigens but these are particular to each person so for example I have type B blood and so that might means that my IM immune system recognizes these type B antigens these type B glycoproteins if I got a blood transfusion that had type A blood in it my immune response would try to attack those blood cells okay so it can cause rejection with the wrong blood type and that is all due to these glyco proteins so lots of different forms and functions of carbohydrates