Four Classes of Macromolecules

Hi in this video we're gonna be talking about the four classes of macro molecules. So the first macro molecule I want to talk about is that of polish sacha rides which are otherwise known as sugars or carbohydrates and they are responsible for cellular energy storage and support. So mano Sacha rides are the building blocks that make up larger policy aka rides. So monos aka rides are these small subunits that repeatedly added together to create these larger policy aka rides. Now, how are these monos Ackroyd's attached? They're attached to these bonds called like acidic bonds, which happened between a carbon and hydroxyl group on each mono sack ride to attach them together. And policy rights can form linear structures. So just sort of align or they conformed ring structures but essentially they're just repeating units of this chemical formula C merges a carbon to hydrogen and an oxygen. So the N. Is standing for repeating. It is so that can be too, that can be 10, that can be 200 repeating units to make up larger um Policy rides. Now there are two main classes. These consists of Aldo's and keto. Those are the two main classes and the class is determined based on the position of a carbonnel group. So just looking at this example right here, you can see here there's a carbonnel group on the end and so this is actually an al dose and then here you have the carbon a group in the middle, which is the ghettos. So in cell biology we think of um policy aka rides in terms of these these larger complex molecules that are responsible for storage and structure. So in plant cells these are starch and cellulose. So energy is stored as starch and support is provided by cellulose. But in animal cells it's actually glycogen. There isn't animal cells don't have cellulose in them or starch. So they have glycogen and that's responsible for storing chemical energy. Now, typically policy back rides are named by the number of units sub units they contain. So these are a number of mono sack rides. So the first one is a mono sack ride and that's gonna be one sub unit. You can have a dye sack ride which is two sub units. You can have an ala go sack ride which is up to 10 and you can have a policy cried which is more than 11. And so the common sugars you may be familiar with are things like glucose which have one sub unit and therefore is a mono Sacha ride. We have super gross that the dye sack ride with two subunits, lactose is also die. And then we have another one called angelos which you may have not heard of but we'll talk about in future topics but that's just a policy cried. Now we haven't talked about lipids or proteins yet and we will you may be familiar with them from your intro bio class. But there are a lot of policy aka rides that attached to lipids and proteins um that have really important functions in cell biology that we're going to talk about a lot more. So just sort of know there are these things that policy aka rides can attach the different molecules like lipids and proteins and we'll talk about what those are in future videos. So if we look at this example here we have Angelo's which again, if you remember as a policy aka ride, um and it's made up of these bonds called a uh these alpha one through four bonds. So this is just sort of a fancy term that doesn't necessarily that you don't necessarily need to understand the molecular complexity of it. Just know that these bonds refer to which carbon is bound. Um and so here you can see that the bond is occurring between these two, the oxygen occurring between these two carbons. So these are the one and the four um carbons and therefore that's how this name now. So you may, just in case you see this in your textbook, you kind of understand what it means. And so here we have these repeating subunits. Here's one subunit here, there's the end, these repeating units that make up close and there's going to be more on this end. There's gonna be more down here and this is what makes up the policy Ackroyd Angelos and this is kind of what policy back rides look like. So now let's move on

Okay so now we're going to talk about the second class of micro molecules and that is nucleic acids were familiar with nucleic acids already from intro classes but let's just another quick review. Make sure everyone's on the same page moving forward. So nucleic acids are the subunits of DNA and RNA which are responsible for storing and transmitting genetic information. And so each nucleotide contains a base which you're familiar with. But we'll review in just a second a five carbon sugar which is either deoxyribonucleic ribose and a phosphate group. Now there are two classes of bases. These are pure rings or perimeter things and that has to do with their actual shape. So you can see here that pure ing's have a pair of fused rings which you can see right here while perimeter tings only have let me do a different color only have one. So these are my teens and wrong color pure reigns. Now the bases are ones that we're familiar with their A. G. C. T. Or you um adding guanine, cytosine, thiamine or your cell. Your cell is found only in R. N. A. Okay, enjoy that there. But adenine and guanine are the pure rings which have a pair of fused rings. Well cytosine thiamine and your sl or perimeter things. Now you probably have already learned this. Um but these are just good classification. You're going to have to know them if you don't remember them. And we'll review and do some practice in just a second. So um what are the bonds that link? Um different of these bases and these nucleotides together. The bonds that do that are fossil di ester bonds. And they link responsible for linking nucleic acids together. And it's important the order that nucleic acids are linked because the linear sequence is actually in coach genetic information that makes up the genes that eventually become protein. So they can't just link any nucleic acid with another one. It has to be in a specific order. Um And we'll talk about more about how that's done in different topics coming up. So there is a function of nucleotides that we really don't think of that often. We think okay nucleotide store genetic information but we don't necessarily think that they can also store energy. But they do because a teepee which you've heard over and over again in your intro class is actually at a scene triphosphate. And so that's a nucleotide. Um that has a very specific function. Not in genetic information but in supplying energy for numerous cellular reactions. So A T. V. Is going to be really important in the future. And we don't think of it as a nucleotide but it is. And so um so here we're just going to look at a very short DNA molecule here and you can see you have your four bases. Guanine, cytosine, adenine. And timing uh they're bound together here. Um And you can see that the pure greens with the two fused rings always bind to a protein which has the one ring throughout the whole thing. And um yeah and you can also see which we didn't go over here, but you should know from your intro class and also from chapter one that if you remember A binds the T. And G. Binds to see. And you can see this happening here throughout A. And T. G. And C. So now let's let's move on.

So the next macro molecule that we're going to talk about our proteins and proteins are extremely important in cell biology because they are responsible for carrying out cellular activities. So um what are the building blocks of proteins? The building blocks are amino acids. And they are used linked together to make these things called poly peptide chains that then can form proteins which carry out cellular activities. So amino acids have an alpha carbon, a karaoke cell group and amino group. And then in our group. And so if we look at the amino acid structure, you can see all of these groups here. You have the um you have the amino group, you have the R group, you have the car boxes group and you have the alpha carbon. Now sometimes amino acids you may see them called residues. That's another term specifically when talking about you know usually specific amino acids in a protein. And so amino acids are linked together through bonds called peptide bonds between the car boxes group which would be here and then the amino group of an adjacent amino acid. So that would be if let me back out of the way. So it would be if this um car boxes group bound to this amino group. This would be a peptide bond And that's what links amino acids together. So proteins have a variety of different functions and their function is really determined by their structure structural properties. So there are 20 amino acids which you should be familiar with some of them from your intro class. Um but they are arranged in very specific formations for every protein to provide its function. And generally um the way that it has these all these unique functions is because of the side chain which is called which is which we just learned as the R group and the art group each for each amino acid is different. And so that allows the amino acids to have different properties. And so these are groups can be classified as polar or charged or non polar. And there's even this um this group called the other group of amino acids that don't fit into any of these other classifications but all of these different properties allow for the amino acids to give the protein that is making up unique properties. Now there is also um these things called di sulfide bridges which we'll talk about more in the future. But they are bonds between these soulful high hydroxyl groups on the amino acid system. And so they only occur on this amino acid and they're very strong and stabilizing. So if you really want to stabilize the protein structure, you're going to have these di sulfide bridges or di sulfide bonds to stabilize that structure. So if we look at this um sort of polyp peptide chain. So each one of these circles is as amino acid. And if we zoom in on one of them you can see that it contains an amino group, a car box cell group, this alpha carbon and also this our group which has the unique properties that allow for the protein to fold into specific structures that provided a specific function. So now let's move on.

Okay, so another macro molecule that we're gonna talk about now are lipids and they are responsible for the formulation formation of cellular barriers. And so um we're probably most familiar with the lipids that form the plasma membrane which is a barrier of the cell um and its external environment. And we also know from our intro class that lipids are typically non polar, which means that they do not dissolve in water. And so there are many different types of lipids. So we're going to go through each one individually. So the first one that you're probably most familiar with are phosphor lipids and they are they are the lipids that make up bi layer membranes. So things like the plasma membrane or the mitochondrial membrane and they are composed of fatty acids. So what is the fatty acid? It's a long and branched hydrocarbon chain. So you can see this here. So here's the hydrocarbon chain. Um and then it also has a polar group on the end which you can see there now um fossil lipids are composed of two of them. So here's your phosphor lipid right here. So you have your first fatty acid in your second and you have your polar group. So they are empathic. Which means that they contain both hydra filic and hydrophobic parts. So here you have your hydrophobic hydrophobic and you have your hydro filic part. So that's a possible lipid. Now another class of lipids are fats and they are really responsible for energy storage. So one of the most common fats are triglycerides and they're actually composed of three fatty acids. So you can see 123 and they are linked by an ester bond to a glycerol molecule which you can see here on the end now they these fatty acids can be saturated if they do not contain double bonds or unsaturated if they do so for this first fatty acid, it does not contain any double bonds. So this one is going to be saturated where this, whereas the second one has a double bond right here, so this is gonna be unsaturated and then the third one has no double bonds. So this one is gonna be saturated and um the saturation of molecules are fats plays a big role um and sort of rigidity and flexibility of the molecule. And we're gonna talk about this a lot more in future lessons. Now, fats are extremely important because they store energy. And so one g of fat actually stores twice the energy of one g of carbohydrates or policy aka rides. So they're big energy storage molecules. And we know this I mean it's very hard to lose fat when we're exercising and that's because it stores so much energy. Now, another class of lipids and the final class that we're going to talk about our steroids. So steroids are a class of lipids responsible for hormone signaling and they play a major role in membrane structure. And we're not going to talk about their roles today but know that we will talk about them in the future. And so steroids look different than the other lipids that we talked about because they actually are these rings. And you can see here down here cholesterol, which is a really common example in cell biology. Um that's found really in cell membranes, um has this very distinct ring structure compared to, you know, something like a triglyceride, which looks like a traditional fatty acid with these long hydrocarbon chains where steroids are much more. Um you know, in these ring formations. So now we've talked about lipids, Let's move on.