hello welcome back everyone this lecture is going to be covering the second part of chapter oops second part of chapter two from your marib text which is covering um in this section we are going to be talking about biochemistry okay and biochemistry is a study of chemical composition and reactions of living matter all right so all compounds are either going to be classified as organic or inorganic inorganic compounds are inorganic because they do not contain carbon whereas organic compounds do contain carbon okay so some examples of inorganic compounds you have water salts and many acids and bases which we'll talk about a little bit more in a second organic compounds are again anything that contains carbon so carbohydrates fats proteins and nucleic acids and they're usually going to be large and covalently bonded and i remember we just talked about covalent bonds covalent bonds is when two atoms share their electrons right to try to make their valence shell full so carbon has um six electrons total so the first shell holds two the second shell then would only be um have four so carbon wants to get eight electrons in its valence shell so it's going to want to share four electrons with another molecule or atom okay so carbon is going to be conv covalently bonded and it's going to make organic compounds all right so let's start with some inorganic compounds so at the top here and the rest of the slides i just noted if you're talking about inorganic or organic just to keep everything straight so the first inorganic compound compound without carbon that we're going to be talking about is water this is the most abundant inorganic compound and it accounts for about um 60 to 80 percent of the volume of all living um i don't know if you've seen the memes where it just says we're all just sad cucumbers because we're all just water with feelings um but the majority of the human body is made up of water okay and it's really important because of some specific properties and i'll go through each of these in detail but has high heat capacity high heat of vaporization um polar solvent properties reactivity as well as cushioning okay so what does all that mean high heat capacity um is the ability to absorb and release heat with little temperature change so water is really good because prevents sudden changes in temperature okay so our body is mostly water and because of that if we step outside in the sun we don't immediately get hot right the water in our body prevents our body from changing temperature um suddenly which obviously we don't want we already talked about homeostasis and how we want to maintain normal body temperature which is 37 degrees celsius water is what allows our body to maintain that um to some extent right and then we have other physiological processes that we can use to warm up or cool off our body if it gets too far out of that range okay the second property high heat of vaporization evaporation requires a large amount of heat okay and it's useful for a cooling mechanism so again really important in maintaining our homeostasis with our internal body temperature the water's ability to evaporate and use up large amounts of heat it allows our bodies to be cooled off more efficiently okay the next property is the polar solvent property so over here on the right we have a drawing of the water molecule what type of bond is uh water bonded by the hydrogen and oxygens okay you should know it's covalent is it polar or nonpolar you should know that it is polar okay we already talked about that if you're not sure what that means go back and review our um part one of this lecture but water molecules are polar covalent bonds which means they create a dipole okay a dipole is a partial separation of charge we have one side that's partially positive where the hydrogens are and one side that's partially negative okay over by the oxygen this means that if you use water as the solvent the liquid that's going to dissolve the solute in some sort of solution that means if you place an ionic compound so a substance that has ionic bonds into water where you have this dipole it's going to be able to to dissociate the ionic compounds which means if you have sodium chloride together cna and cl when you place that into water sodium is a positive ion cation chloride is going to be a negative ion an anion when you put that in with a water molecule since the sodium is positively charged the partial negative on the oxygen molecules is going to want to bond to it so this is our poorly drawn water right our oxygen molecules that are partially negative are going to be attracted to the sodium so you can see here the negative oxygen regions of the polar water molecules are attracted to the sodium cations whereas the chloride anions is going to be the opposite so the hydrogen the two um blue parts here is what i'm drawing these circles those positively charged partially positively charged hydrogens are going to be attracted to the chloride so what's going to happen is these ionic compounds so sodium chloride are going to dissociate which means they split up into their individual parts when they're placed in water okay and we'll talk about this a lot more in lab and in some upcoming chapters where we talk about diffusion and osmosis but it's really important to know that ionic bonds dissociate when put into water okay and this is another reason why water is so important because allows us to transport um a lot of different electrolytes and salts through our body which is really important to keep our body moving okay then two more properties of water reactivity is a necessary part of hydrolysis and dehydration synthesis reactions which we're not really going to talk about in this class too much just because it's a bit over our heads but it's important in a lot of chemical reactions you need water for some chemical reactions to happen and then finally cushioning which is very important water is going to help protect certain organs from physical trauma so your cerebral spinal fluid is a watery fluid that surrounds your brain and spinal cord and it helps cushion it so to make sure that if you get hit in the head hopefully there's enough fluid there to cushion your brain so that it doesn't cause physical damage to your nervous tissue obviously if you get too hard of a hit it's going to damage the tissue but the fluid acts as a very good cushion okay so those are all physical properties of water and why that's such an important inorganic molecule the next inorganic molecule are salts which you should already know are ionic compounds right ionic bonds are bonds remember where um the electrons are transferred right so for example our sodium chloride right um sodium loses any electrons becomes partially a positive charge and chloride gains an electron so it becomes more negatively charged and again remember we're transferring electrons to try to make our valence shells either full or get rid of extra electrons we have to move down a valence shell step okay and we talked about already that salts dissociate into their separate ions in water so sodium and chloride when placed in water are going to separate and be individual and then separate into cations which are the positively charged molecules and ion anions which are negatively charged okay we've already discussed that ions are called electrolytes because they can conduct electrical currents in solution and it's really important for our bodies to have these different electrolytes or salts or ions floating around in our fluids helps with a lot of physiological processes well it says it right here ions play specialized roles in body functions so sodium potassium calcium and iron specifically really important when we talk about muscles and how they contract the physiology behind muscle contractions or when we talk about action potentials being transmitted through the nervous system you will see all of these ions play a major major role and if we don't have those ions present our body can't function like it's supposed to okay also very important in homeostasis and then just some common salts you don't have to memorize those but i included them i don't know if you wanted to know okay then the next two inorganic molecules we're talking about are acids and bases um which i'm going to try to simplify a little bit because we'll talk about this more later on but um very basically acids are protein donors proton excuse me proton donors which means they release hydrogen ions okay hydrogen ions are positively charged so is that a cation or an anion cation bear protons into solution bases are the opposite so they're proton acceptors so they are going to pick up spare hydrogen ions in solution okay um when a base dissolves it releases a hydroxyl ion oh negative um that's going to pick up the h positive so so important acids listed there important bases um you'll see this a lot in bi 208 when you talk about the respiratory system and your acid and base balances in the blood gas exchange and stuff like that okay we can measure um acid base with the ph scale so it's a measurement of concentration of hydrogen ions in a solution um acidic solutions have high concentrations of hydrogen ions but the ph is low so let's see on here um these low ph's are acidic okay which means that they have more concentration of hydrogen ions neutral solutions fall in the middle around a ph of 7 there they have equal numbers of hydrogen and oh minus pure water is neutral and then the last one is your basic solutions or alkaline same thing they have low concentrations of hydrogen and a high ph okay so on the scale above seven and this would be your basic solutions there there's some examples here so basic solutions different oven cleaners different household cleaners ammonia bleach egg white is basic blood is a little bit basic acidic solutions obviously some of them are kind of straightforward so things like lemon juice coffee wine um and obviously like strong acids that you would see in lab okay so that's acid and bases so those are inorganic substances now we're going to be talking about organic and again things that have carbon in them are considered organic okay carbon is considered electro neutral which means that it shares electrons it's never going to gain or lose them so you're never going to see carbon in any sort of ionic bond instead it's always going to want to form four blank bonds with other elements can anyone tell me what's supposed to be in there anyone answer it would be four covalent bonds okay it's never gaining or losing your electrons it's just going to share and sharing electrons is what forms covalent bonds okay so some organic compounds we're going to talk about carbohydrates lipids proteins and nucleic acids most of these are what we consider polymers which are long chains of smaller subunits that are called monomers okay so monomers are like individual small subunits say this is a monomer this is a monomer this is a monomer if they all be get combined together to form like a long chain say these are attached now that whole thing's a polymer right so a polymer is made up of individual monomers okay so all carbohydrates lipids proteins and nucleic acids um those are all examples of polymers so the monomers are going to be the building blocks we're going to talk about that make up those larger units okay so let's start with carbohydrates again organic because it contains carbon um sugars and starches are examples of carbohydrates three classes of them monosaccharides which is just one simple sugar which is just another name for a monomer of a carbohydrate we have disaccharides which are two sugars together and polysaccharides which is many sugars again polymer um is another name for a polysaccharide right so fibers each circle is a monomer so each circle is a monosaccharide for a disaccharide we'd have two monosaccharides or two monomers together in a polysaccharide you'd have many monomers or monosaccharides in a long chain okay so here's some common examples of monosaccharides first again carbohydrates are just sugar so you have glucose fructose galactose deoxyribose and ribose again you can see all of them let me get brighter color all of them are just this one monomer all right this is a single um carbon ring disaccharides sucrose maltose lactose you can see each one of these is made up of two individual monomers so sucrose is glucose plus fructose maltose is two glucose molecules together right so disaccharides have two monomers and then polysaccharides are long chains so for example glycogen you can see this whole thing this is a long chain of monomers that have been added together and they form these different long shapes okay so that's a polysaccharide [Music] the next class of organic molecules are lipids which are just fats they're insoluble in water and there's three main types which we'll talk about a little bit later on um your book has this table here i'd recommend you go through and take a look at those some more information that what that that i may not talk about but is important so first triglycerides are called fats when they're solid and oils when they're liquid okay so lipids are kind of the names kind of interchangeable with fat but when they're solid they're considered fats when they're liquid they're considered oils triglycerides are composed of three fatty acids bonded to a glycerol so our fatty acids are going to be these three fatty acids here right so those are our fatty acids bonded to you're not going to be able to see any color i'll do gray bonded to those glycerol molecule up top okay that's the general makeup of a triglyceride main functions think of you know what you think of fat being the function in your body energy storage insulation and protection so help keep your body at a normal body temperature store energy for later use and then add that fatty cushion to help protect deeper tissues these fatty acid tails here that there's three of them in the triglyceride they can be in two different forms okay so you have either saturated or unsaturated fatty acids saturated fatty acids all carbons are linked via a single covalent bond okay which means you have the maximum number of hydrogen atoms possible it's saturated right saturated with hydrogen these create linear molecules which can close packedly to get close packed closely together forming a solid at room temperature i'm gonna do that different color solid at room temperature okay so any fat that's solid at room temperature different animal fats butter is considered a saturated fatty acid again because you have the maximum number of hydrogen molecules possible and i'll show you an image of that in a second [Music] the other type unsaturated fatty acids some of the carbons are linked by double bonds which means you don't have the full amount of hydrogen okay the double bonds causes kinks so it can't pack closely together so unsaturated fatty acids are liquid at room temperature okay so plant oils such as olive oil avocado oil um canola oil a lot of things oils you see like in cooking those are all considered unsaturated okay and two more specific examples which we're not really going to talk about at all in 207 but you'll kind of get when we talk about digestive system in 208 trans fats and omega-3 fatty acids um just kind of interesting but you don't have to know those okay so here's what saturated fatty acids look like again saturated because you have a straight line right and you have as many hydrogens attached as possible again these are going to be solid at room temp whereas unsaturated we're going to have a double bonds at some points which is going to cause a kink in our um our chain here which is going to make this knot pack closely together which means it's going to be liquid at room temp okay phospholipids is a specific type of lipid you may have heard about before it's a modified type of a triglyceride which it just has the glycerol and two fatty acids instead of three but it also has a phosphorus head group um so this phosphorus head group so that ends up giving us a head and the taylor region the taylor region is these fatty acids fats are going to be hydrophobic the head group is polar um water is polar so it's going to be a hydro philic which means it likes loves water okay so you're going to see these phospholipids make up our cell membrane which we'll talk more about in chapter three um but they form this bilayer so you have the polar heads on the outside so say this is the outside of the cell so you have water outside the cell you have the fatty tails along with other fatty tails creating this semi-permeable membrane and then the polar heads on the inside of the cell where you'd have the cytosol right the internal contents of the cell okay that's the phospholipid bilayer because there's two layers the last type of um fats are considered proteins so these are four interlocking ring structures um most important one that we're going to talk about is cholesterol um a starting material for synthesis of vitamin d steroid hormones and bile salts so a lot of things in our body are made of steroids um it's really important in the cell plasma membrane structure which again we'll talk about more in the next chapter so this is what a typical steroid looks like you'll just see these four ring structures and depending on this group attached to the ring structures it'll be a different type of steroid okay but this is the basic um look of a steroid okay next organic molecule we're going to talk about our proteins which comprise 20 to 30 percent of our cells mass have such varied functions um there's proteins for everything do everything structural proteins functional proteins chemicals that are proteins um the polymers of amino acids are held together by peptide bonds so the monomers in this case are the amino acids right so the individual building blocks are going to be amino acids so say we have a bunch of amino acids here right they're going to be held together by peptide bonds right so that's what makes up our proteins again our monomers are the individual amino acids the shape and function is due to four structural levels which we'll just briefly touch on um here's the different types of proteins you can have i'm not going to worry about this too much right now because and later on in the semester we'll talk about all these different things in detail so just know that proteins have a wide variety of functions as long as you know that you should be pretty good so again amino acids are the monomers the building blocks of your proteins and again they're joined by the peptide bond here um in the middle okay i'm not going to ask all these fancy questions about the amino acids and stuff i'm just no amino acids are the monomers held together by the peptide bond and then the structure of protein there's four different levels of them so we have primary secondary tertiary and quantum quantitary [Music] i'll show you images of these i think you can pause and write this down if you want this in your notes but i think the pictures kind of make it more more make it make a little bit more sense okay so the first is the primary structure which is just the sequence of amino acids in the chain right so here are individual amino acids all lined up again the amino acids are our monomers so just the sequence in the single chain is the primary structure okay this primary structure is going to fold up um and create more complex shapes and that's considered the secondary structure so we can either sporm form alpha helices or beta sheets okay so helices the these this primary structure is going to coil right and form a helix shape and it's held together by hydrogen bonds so you can see right if the blue is hydrogen and we have oxygen between the hydrogens and oxygens you form these hydrogen bonds that are going to keep this in a spiral shape right these hydrogens and oxygens on the original primary structure as that folds up it's going to create this helix shape or you can have these beta sheets which is similarly held together by hydrogen bonds as well between again the oxygen and the hydrogen molecules okay oops then we have our tertiary and quantitative structure tertiary um is just superimposed so you have helices or beta sheets are formed are folded up even further to kind of form a globular molecule again there's going to be bonds that hold all this together but you're going to have alpha helices helices different beta sheets all fold together to make a tertiary structure and then quaternary structure is going to be two or more of the chains each with its own tertiary structure form together to form a functional protein okay so you're going to have multiple tertiary structures coming together to form a big functional protein okay as long as you know the four different types of structure and just very generally how they're made you'll be okay the shapes of the proteins you can differentiate into two categories the first is fibrous which is structural proteins so they're not functional these proteins are strand like um they provide mechanical support and tensile strength so things that are in our body that are just there to help hold everything together so keratin elastin collagen the different proteins that we find in our skin and in our connective tissue that are there just to help make our body shape what it is are fibrous or structural proteins we also have globular or functional proteins which are the proteins that are actually going to be doing the right so they're going to be compact um spherical water soluble sensitive changes they're going to be things such as antibody hormones enzymes you have different protein channels things that are actually gonna serve some sort of functional purpose in our body um enzymes help digest um catalyze reactions whatever right so um these functional proteins are what's actually going to be doing the work okay and those functional proteins are can be subject to what we call denaturation denaturation which is when those proteins unfold and lose their shape so the only reason they're able to do the job that they're supposed to do is because they're in their specific shape and we'll talk about it a little bit more later on but that shape allows them to bind to other molecules other chemicals and do their specific job so if they're in a situation where they have decreased ph an acidic environment or increased temperature it can denature the protein okay which makes it no longer functional so an example of this um in your saliva you have a protein an enzyme specifically called savillary amylase which is important in digestion of starch or the polysaccharides so when you're chewing a cracker in your mouth if you leave in your mouth long enough you'll you'll start being digested by this amylase as soon as you swallow that food and it enters your stomach your stomach has a lot of hcl in it that decreased ph is going to denature the amylase right so starch digestion will stop once the starch and animals hit your stomach no more digestion is going to happen because it's too acidic of an environment okay so that's just one example um if it's not super severe of a denaturation it can be reversible but in extreme changes it's irreversible so cooking an egg is an example of denaturing that eggs proteins obviously once you cook something you can't uncook it so in very extreme situations it can't be reversed okay enzymes like the amylase we just talked about are examples of globular or functional proteins that act as catalysts um they increase the speed of chemical reactions um and they don't get used up within the process so you can have salivary amylase a little jar of it and it'll continue to um break down starches over and over and over again you don't need um necessarily to create more amylase as long as yours is still good um enzymes are specific we'll talk about this again more later on but each enzyme the way the protein is folded into its tertiary structure it can only act on a specific substrate okay so amylase again amylase um digests starch or polysaccharides we have a enzyme protein called lipase that digests lipids okay um amylase can't digest lipids because the shape of the enzyme only allows it to bind to a specific substrate which in that case would be starch okay um often the names end in ace amylase lipase so anytime you see that it's a good indicator it's an enzyme it's often named for the reaction that they catalyze okay again this is kind of reiterating what i already said but it lowers the activation energy which is the energy needed to initiate a chemical reaction so for example breaking down a polysaccharide into monosaccharides digesting starches without the enzyme it's going to take a lot of energy for that to happen with the enzyme it's going to happen a lot more efficiently so it's going to reduce the amount of energy needed and allow it to happen more quickly at body temperatures okay um three steps in enzyme action this is pretty straightforward but first your substrates bind to the enzyme right the complex undergoes rear rearrangement of the substrate so the enzyme does whatever the enzyme is doing okay and then the product the product is released from the enzyme okay and then this enzyme again doesn't get used up in the process so this enzyme can go on and continue to do this work with other substrates okay our last type of organic molecule are nucleic acids um they are the largest molecules in the body their monomers are called nucleotides okay so your nucleotide monomers right we talked about before bound together make up nucleic acids okay and there's two main types of nucleic acids which these hopefully are familiar with you deoxyr ribonucleic acid and then just ribonucleic acid which if you don't know what those are dna and rna okay so dna holds a genetic blueprint for the synthesis of all proteins we'll talk about this more in the next chapter um it has a double stranded helical molecule again the nucleotides contain deoxyribose sugar a phosphate group and nitrogen bases adenine guanine cytosine and thymine and the bonding of these bases are very specific so a always pairs with t g always pairs with c okay and don't stress out too much about this um this is an intro biology class so you don't need to memorize everything here but again you have the sugar phosphate backbone so these purple spirals and then the rungs are the um nucleotide bases okay and they're going to pair together and form this double helix so that's dna rna is very similar but it's just a single stranded molecule contains ribose sugar instead of deoxyribose um the base thymine is replaced with uracil um there's different types of rna again don't stress out too much about this stuff i'm really not super worried okay so here's the list of monomers and polymers we've talked about so for carbohydrates your monomer is a monosaccharide polymer was the polysaccharides proteins are monomers with amino acids polymers wore the proteins or polypeptides and then nucleic acids monomers were nucleotides and then our polymer would be either the dna or the rna [Music] okay and then the very last bit here really quick i just want to mention atp a does an adenosine triphosphate that is where our body is going to get energy so atp directly powers chemical reactions in our cells it offers immediate usable energy um and you have i'm not worried about the structure really here but you have the adenine containing rna nucleotide with two phosphate groups and we'll see this throughout the rest of the semester in 207 that atp is needed in a lot of different processes in our body so transporting materials through facilitated diffusion which we'll talk about in the next chapter mechanical work such as contraction of muscles and chemical work so driving and absorbing chemical reactions in our body okay so that is the end of chapter two let me know if you have any questions