now these are examples of equations that actually happen in your blood for example if your blood starts to acidify you're going to have this reaction happen this is the extra hydrogen ions they're going to combine with this substance this hydrogen is now combined here and we're going to take those extra hydrogen ions out and we're going to bring the blood back to homeostasis if it starts to become too basic by the addition of the hydroxyl ions again this compound is going to accept this through this reaction we're going to absorb those ohs and we actually get water out of this particular chemical reaction again that's how we're going to maintain the human body's blood okay we've talked about bonding we've talked about acids the different types of bonds we're ready to talk about molecules and the different types of molecules that are important to life we talk about organic molecules there are two common things they always have carbon they always have hydrogen now we can have molecules that are strictly made up of hydrogens and carbons and these are called hydrocarbons hydrocarbons tend to be things that we use for energy gasoline propane things like that things we use to make something happen so the chemistry of carbon accounts for the formation of a great variety organic molecules if we look back and we talk about carbon a little bit we saw that on some of those examples it needs four more electrons in its outer shell those outer shell electrons are called valence electrons carbon is happy when it has that outer shell with eight full electrons and so it's going to tend to do that in organic molecules a carbon atom may share electrons with other carbon atoms so we can have carbon on carbon or other types of atoms to achieve those eight electrons remember that's called the octet rule when we get into that second third and fourth shell one way we can have different organic molecules is have something called functional groups these functional groups are actually going to change the properties of the individual molecules we can talk about hydroxyl groups this is going to be our o-h carbonyl groups is a carbon doubly bonded to an oxygen remember this single line was a single bond when we start to see two lines that's a double bond to oxygen carboxyl amino groups these are going to be important we start talking about proteins and then a phosphate group is going to have a phosphate right in the middle that we'll talk more about this when we talk about atp and things like that so all organic molecules are built from monomers a monomer is like a building block a polymer is many of those building blocks now macro in biology means relatively large macromolecules have lots and lots of monomers in them so monomer is an individual polymer is lots of these monomers put together so some examples so polymer these are going to be our macromolecules we're going to talk about carbohydrates we're going to talk about proteins we're going to talk about nucleic acids so polymer again means many the building blocks of these for carbohydrate is called a mono saccharide single sugar protein is an amino acid and then a nucleotide is a nucleic acid is built up of nucleotides so this is the individuals and then we're going to stick them together to build these larger molecules now to join the monomers are the building blocks we're going to use something called a dehydration reaction this is going to involve water remember water had that slightly stickiness to it we call this the hydrogen bond and when we stick the monomers together on one end we're going to remove the oh and then on the other monomer we're going to actually remove the h and then we're going to form a water molecule now the sites on those monomers where we took those off that's going to cause those monomers to stick together that's how we're going to start building those polymers when we break things down like as we're doing digestion and we're starting to eat stuff we need to break down that stuff we're going to use a hydrolysis reaction where we're going to reverse what we just did in the dehydration reaction we're going to put water it's going to separate the monomers and then we have the individual building blocks of that macromolecule so let's look at this a little bit on one side we have a monomer this side we have a monomer now on one end of it we have this h that sticks out on the other side of it we have an oh that sticks out if we can take these two off we get water that's simple water and what that does is it exposes this end and this end they're going to form a bond where now we actually join these monomers together this is a polymer where we have two or more monomers joined together most of the time these are going to be thousands of monomers long especially when we start talking about proteins now if we want to take this back apart we need to do the opposite we're going to put the water back in and so to do that it's going to require water we're going to split this bond return the oh to this side put the h on this side and then we physically separate these two we've actually broken down this polymer this is how digestion works in your digestive tract we want to break those larger molecules like proteins and starches into the individual pieces that we can flow through our bloodstream let's look at our first macromolecule carbohydrates we know carbohydrates in fact we often craze these crave these these are usually sweet things or starchy things and our body is pretty efficient at breaking them down so it's a nice quick energy burst now in other organisms like plants they're going to perform part of the structural component in bacteria and insects they're also going to conform they're going to have some functional aspect as well carbohydrates we can find these on some of our cells in our bodies our blood type is formed by the absence or presence of certain carbohydrates so the system is all functioning on what type of carbohydrates are on that cell now carbohydrates start off with monomers and those again are called monosaccharides monosaccharides can be anywhere from three to seven carbons in them and often what they do is they form rings pentose for five this is a five carbon sugar hexose hexose hex is six this is a six carbon sugar this is something like glucose this cartoon is a representation of glucose it shows all the components if you go around here you would count six carbons the sixth one being right there you see that hydrogen and oxygen are major components to that but it's going to have this nice ring structure we can simplify that with this structure take the carbons out and we just put the other things in but usually what we see especially after you learn this structure they'll just represent this as glucose they'll show you the oxygen you see the six-sided structure and we know this is glucose glucose has six carbons 12 hydrogens and six oxygens now disaccharide dye means two and so we're gonna take two monosaccharides and we're gonna join them together by the dehydration reaction remember the dehydration reaction we're going to clip off an oh and h take out that water and then we're going to join them together and then we have our disaccharide again glucose glucose dehydration reaction we get something called maltose now if we want to digest that we have to break it down then we're going to do the hydrolysis reaction add the water back in and then we split that bond and these are easily absorbed into the digestive system now polysaccharides these are three and more and these are more common polysaccharides can be described as starch glycogen and then cellulose in plants now starch we're going to use these in plants plants to do this to store excess energy that they've done in photosynthesis and then we actually take advantage of that this forms a major component of our foods polysaccharides each one of these contain up to 4 000 glucose units and then glycogen this is storage in animals for excess energy it's made up of glucose but there tends to be a lot more branching with glycogen so you need to remember that starch is the way plants store extra energy glycogen is a way that animals store excess energy and then most of the glycogen is stored in the liver and then in your your muscles for energy here's an example of starch so we have lots and lots and lots of these glucose molecules and then just keep going and going and going remember up to about 4 000 if you will again this is what potatoes do starchy vegetables do this as well the wheat corn things like that this is glycogen again you have those same glucose molecules but now there's lots of branches uh there's lots of inner connections in here and again this can be stored in the liver or your muscles actually store quite a bit of glycogen as well now cellulose is found in plants and this is going to be a structural macromolecule for plants to help toughen up the cells in some cases to help them grow taller so cellulose is found in the cell walls of plants it accounts for the strong nature of those cell walls again in part lets those plants stand up straight it's put together a little bit different than starch or glycogen it is made up of lots and lots of glucose molecules but now they're going to be branched and they're going to form more of a almost like a lattice kind of structure those extra bonds is why we can't we can't break it down that's what cellulose is going to pass right through our bodies and this is commonly called dietary fiber which is which is good for us now chitin this is formed in the exoskeleton or the outside shell of crustaceans like crabs and it allows them to protect themselves but it's another structural polysaccharide so here is cellulose in the plant wall so this is going to be different than starch in that we're forming these long fibers of the glucose sugar and then when they come into contact they actually start to connect to each fiber that's adjacent to it so we have a nice fibrous um component to these cell walls again this is dietary fiber it's actually it's actually good for you our next macromolecule are lipids these are going to have twice as much energy than any of the other macromolecules we're going to talk about we just finished up talking about carbohydrates per gram they average about four calories lipids are going to have anywhere from eight to nine to ten calories per gram so they're really what's considered to be energy dense different types include fats and oils these are mostly for energy storage phospholipids we'll talk a lot more about these when we get into the cell chapter these are going to help us form cellular membranes and then they're component of hormones hormones we'll talk a little more about when we get further into the to the course but hormones circulate around in organisms to help control cells so lipids have lots of different structures lots of different components to them and form and function is something that we're going to introduce right now the way something's put together is going to change the way it operates or what its function is but lipids have one common characteristic that they do not dissolve in water remember hydrophobic that's what lipids are they're hydrophobic they're water avoiding or water fearing so two types of lipids are fats and oils now fats are usually from animals and usually they're solid at room temperature normal room temperature function is to store energy insulate against heat loss and form a protective cushion so lots of energy can be stored in fat we already talked about it's about twice as dense as calories some animals especially when they live up in the northern parts of the of the globe they use it for literally insulation and then they can store energy in that same layer when they hibernate for months on time now oils are usually liquid and they're made by plants so fat is a molecule is known as a triglyceride for three components so triglyceride has a glycerol backbone in three fatty acid tails so the glycerol is this box it's got a bunch of carbons hydrogens and there's some ohs hung out here fatty acids are chains of carbons and hydrogens literally storage of excess calories and then when you put the fatty acids with the glycerol then we get a complete fat molecule or a triglyceride so fatty acid is a hydro hydrocarbon chain remember hydrocarbons are nothing but hydrogens and [Music] carbons and this is a great way again to store energy but they also have an acidic group a co h group that's going to identify them as a fatty acid saturated fatty acids all have single bonds unsaturated fatty acids have one or more double bonds remember a double bond is where we have two electrons involved in that same junction between the two atoms it turns out that saturated fatty acids um they tend to be straight so they're gonna have this nice straight component to them not gonna be any bending in here this is mostly gonna we're gonna find in animal animal fats these are generally considered to be unhealthy because of this flat nature they have the ability to form plaques in arteries and kind of lead to the closing up of some smaller arteries in general are not considered to be too healthy now the ones with the double bonds what that does is in the molecule itself it creates these bends it creates these kind of angles in here and so unsaturated fats tend not to form those plaques on the walls of arteries and you have less trouble with these in general it said that unsaturated fatty acids are actually much better for you because of that reason so if you can you want to lean towards these unsaturated fatty acids now phospholipids are important to cell membranes now phospholipid by definition are composed of two fatty acid chains and a phosphate group now the phosphate group the way it's put together is polar and so when we have something that's polar we know that we have charges on them and what this does in in this phospholipid it creates a hydrophilic and hydrophobic component to it remind remember hydrophilic is water loving and then the tail is going to be hydrophobic or water fearing now when these are put together in a solution especially around a cell what they do is the polar head with the phosphate in it the little p there you might be able to see that i'm circling this becomes hydrophilic the nature of the tail is the way they're put together they become hydrophobic and so when these come together they automatically form this layer where all the phosphate heads point to where there's more water they love that water inside of the cell is mostly water outside of the cell is mostly water in the tissues and then inside between these two layers is relatively dry because it's occupied by all these fatty acid chains this is going to form the plasma membranes of the cells we're going to talk a lot more about that in the next chapter it's really important to life now steroids are our next class of lipids they generally form structures that have rings into them and they're generally involved with hormones circulating through the through the body examples are cholesterol cholesterol usually gets a pretty bad route but it's actually pretty important to cells and cell transport and cell recognition and then some of the other hormones testosterone for males estrogen and females all have this steroidal component to them or this lipid component to them now proteins are probably the most abundant molecule in the the body itself they are pretty complex polymers so there's lots of parts to them and they're all composed of amino acid monomers now an amino acid is made up of components it has an amino group amino is for the nitrogen the acidic group denoted here this is an acid and then the r group is going to be the functional group this is going to give the amino acid its property and so here's an amino acid we have this double bonded oxygen over here we have this o h the r again is the functional group that's what's going to give each of the amino acids its own individual individually now these are the monomers we have an o h here we have an h here if we take that off you guessed it we're going to have a dehydration reaction that's going to lead these two monomers in forming that polymer eventually here's just a couple examples of amino acids alanine valine cytosine and p-e-p-h-e all have the same group except for the r group so all of this is the same on the outside but all of this shaded component is what gives each of these amino acids its own individually kind of function remember form and function so proteins they do a lot for us there are structural proteins we have proteins called keratin in collagen keratin is a component of your hair it's component of your fingernails it's a component of your skin so structure collagen is a binding protein it's probably the most abundant protein in your body this is what makes up your dermis in your skin this is what's going to join the muscles to your bones by the tendons proteins are enzymes enzymes are structures that help with chemical reactions hormones we've talked a little bit about hormones but hormones basically control cell function so they're going to act as messengers actin and myosin these are special proteins found in the cells of all muscles they're gonna allow for contraction or movement of those muscles there are some proteins that help to transport other molecules in blood kind of act like a shuttle or a conveyor system in your bloodstream and then proteins are also antibodies which is very important for our immune system proteins also are embedded in the plasma membrane and they actually act as channels or in some cases pumps to bring things in and out across the plasma membrane peptides peptides a polypeptide is a single chain of amino acids and a peptide bond is going to join those amino acids peptide bond is specific when we're building proteins but it's going to look really familiar we're going to take this oh we're going to take this h off that's going to form water and then we join these together through that dehydration reaction now when we eat proteins we have to do the opposite we have to do hydrolysis that's why water is important to overall health and part because you need that water to go back in here and break these bonds so we can digest those individual amino acids now proteins have lots of complexity to them four levels in fact now the primary structure is just the arrangement of the amino acids just the order in which they come together now the secondary structure is after that primer structure has been completely built now we're actually going to contort that linear chain of amino acids into two primary structures we're going to call them the alpha helix and the beta sheet and what happens is the individual amino acids either repel each other or they attract each other and they form these complex structures helix is going to be like a coil like a spring and this sheet is going to be like a folded piece of paper after that we move into our third level this is called the tertiary structure where the final three-dimensional shape is is finally reached in that protein we have the sheets we have the helixes we have all kinds of bonds we have covalent bonds ionic bonds hydrogen bonds when we haven't talked about disulfide bonds that's going to give that protein a very unique shape and that shape is going to dictate what type of function it is it's very very specific you have tens of thousands of different proteins in your body each one of those has a distinct role based on its shape after that we have the quaternary structure this is where you're going to take two or more proteins and you're going to bind them into a larger structure that again is going to change its shape it's going to change its function so we had primary up here at the top this is simply the order in which the amino acids are put together when we get into other chapters we're going to see this is controlled ultimately by your dna or the dna is in that cell secondary structure we're either going to have the alpha helixes which is going to form these coils or ribbons or the pleated sheets which are going to be like folding a piece of card stock or a piece of paper into this and you're going to have both normally in a in a protein so it's going to give it lots of variability tertiary structure we've actually reached the complete structure of that protein and again each one of these is going to have its unique shape depending on the order of the amino acids quaternary structure is we're going to take two or more proteins this one shows four they're going to be similar but now because the shape has changed the size has changed this has a different function than this original protein it's all about shape and function with these proteins so again the final shape of a protein is very important to its function and if you change that shape it's going to lose its function it's not going to be able to do what it was designed to do this is called denaturization or when it's denatured it's going to change its shape so it's changing its function this happens when you have acids introduced you cook something you're heated above a certain point or the ph changes in there something changes or you add too much salt to something an example of denaturing a protein if you've ever fried an egg in a pan when you crack that egg you get the yellow yolk you get the clear whites but as you heat it the white actually turns from clear to white you're denaturing that protein you're giving it a different shape so it changes color once you denature protein you can't go back you're done so it's a detrimental it actually loses its complete function that's going to be chapter 2.