[Music] I've run dr. Mike here let's talk about carbohydrates as one of the four major types of macromolecules remember you got carbs proteins fats and nucleic acids also known as nucleotides now carbohydrates if we think about what they composed of you'll find that carbohydrates are composed of carbo being carbon atoms hydrate talking about water we know water is made up of hydrogen and oxygen so carbohydrates are made up of carbon hydrogen and oxygen that's basically it you'll find that all these macromolecules whether it be proteins fats carbs or nucleic acids are simply made up of hydrocarbons being a bunch of carbons connected to a bunch of hydrogen's now when we look at carbohydrates pretty much all of them are in this ring shaped fashion and you can either have them alone which we call monosaccharides meaning one sugar you can have them connected together which we call disaccharides so that's two sugar molecules click together or you can have a whole bunch of them click together which we call polysaccharides now the human body by mass is made up of 1% carbohydrates and predominately we use carbohydrates for energy you'll find carbohydrates on cells in cell membranes you'll find them associated with genetic material but predominantly the functional role for carbohydrates is going to be energy production now if we have a look there's three main types of monosaccharides the simple return the simple sugars and this includes glucose fructose and galactose which you've probably heard of before now if you have a look they are all made up of carbons hydrogen's and oxygens and you'll actually find that they have the exact same chemical formula c6 h-12 o-6 so there's six carbons 12 hydrogen's and six oxygens the only difference between those three is that they're arranged differently so glucose which is our primary monosaccharide this is the main one we used to produce energy you can see this is the arrangement of all the carbons or the hydrogen's or the oxygens okay you can see the carbon ring with all the hydrogen and oxygen coming off then when we look at fructose still c6h12o6 it looks very similar but there are a couple of differences same goes for galactose very similar couple of differences they're termed isomers of glucose in actual fact when you ingest foodstuffs what will happen is once it's absorbed from the intestines into your bloodstream it goes to your liver your liver will convert galactose and fructose to glucose either to use the glucose for energy or to store the glucose as a polysaccharide which we term glycogen but I'll get to that in one second now what can happen is you can ingest these carbohydrates as disaccharides and when you have a look at these carbohydrates for example if you were to connect a glucose and galactose together you'd have to do it through a process called dehydration you've heard that term before dehydration it means you don't have enough water in your body right so a dehydration reaction simply means you release or you remove a water molecule from the reaction it's very easy if we first start off by connecting a glucose with a fructose for example that's terms sucrose so that's sucrose is simply a glucose connected to a fructose the way you do it through a dehydration reaction is water needs to be removed water is h2o two hydrogen one oxygen there's a hydrogen there's a hydrogen there's an oxygen so you remove them away and then those two carbons can click together that's how you form a sucrose in a dehydration reaction when you want to separate them it's a rehydration reaction you're going to put that water molecule back in now if we were to connect glucose and galactose together we form something that's called lactose and some people are lactose intolerant which means when they ingest milk products where you predominately find glucose and galactose stuck together you need an enzyme in your body that snips off that to bonds so remember you got that water molecule that's you've taken away that water molecule the carbons are held together you need to rehydrate to break them apart and you need an enzyme to do this rehydration process when you're rehydrating that of lactose it's an enzyme called lactase ASAE for some of us we no longer produce lactase and so we don't have the scissors that allows for us to cut that bond and so what happens is the glucose and the galactose remain stuck together and continue to move through our intestines we need to break this down into glucose and galactose in order for it to get absorbed it from our intestines into the bloodstream so we can use it if it doesn't snap apart to this hydration process they stay together and it continues to move through the digestive tract now this is a larger molecule and when you've got larger molecules moving in bulk through your intestines it actually pulls water towards it this is called an osmotic effect and if it pulls water towards it now your intestines are filled with water and that goes out in the fecal material which we call diarrhea so this is why lactose intolerance can result in diarrhea okay the other thing is what if we were to click together fructose and galactose well in actual fact this doesn't happen so you don't actually get a disaccharide or fructose and galactose now like I said fructose and galactose will ultimately turn in at the liver to glucose and so now we've got a whole bunch of glucose molecules in our liver we can either use it to form ATP energy or we can store it and click all the glucose molecules together to form what we call polysaccharides which means many sugars now there's different types you can actually ingest polysaccharides from plants and they are called starches or cellulose okay or you can ingest it from animals which is called glycogen and we store our glucose as glycogen okay now the thing is when you ingest a polysaccharide a cellulose from a plant material we don't have the enzymes that break those bonds remember that rehydrate the process so cellulose which you find in leafy greens you also find in lettuce you find even in grass for example if we were to eat grass which we don't do there's heaps of carbohydrates there but we can't break them up into these monosaccharides because we don't have the enzymes now cows for example do have the enzymes so they can get all the energy they need from just eating grass but we can't okay so what happens is we eat lettuce for example we don't break it down but it forms fiber so fire by these indigestible polysaccharides that we can't break down bulks up the stool helps push everything through but we do have the enzyme that breaks down starch and glycogen okay and we can see is the way they're stacked together a different for cellulose it's one long linear bit of glucose connected together starch is a whole bunch of glucose molecules connected together in a branch like fashion and glycogen is extremely branch and this is the way that we store glucose so when we look at macro molecules this is how carbohydrates are stored and made