in terms of E1 uh almost everything I'm going to say right now uh is written here but I would like to suggest that if you have just some blank paper notebook paper anything like that uh I would like to suggest that you pull that out the section e deals with a subject and I will admit it's not quote the sexiest subject in the world but it's actually quite an important subject now uh we're going to be using Solutions uh in this class various Solutions not a lot but a little bit and we should understand what is a solution now in this case we don't mean an answer to a a test question a math problem but we mean a a solution a solution is made up of two things a solution is made up of uh a solute which we pour into a liquid so we've got a beaker here that I drew and whatever you add or dissolve in the liquid that's called the solute now this solute could be salt maybe we're pouring salt in the uh liquid and liquid's usually water it doesn't have to be water the liquid could be rubbing alcohol it could be uh uh the alcohol that like whiskey alcohol could be ammonia could be gasoline it could be vegetable oil but obviously uh in biology and in medicine the liquid usually is water so uh whatever we add to the water so if it's salt it's a saltwater solu solution if it's sugar it's a sugar water solution so solution is made up of two things if the liquid is water we call it an aquous solution aquous a u u e o u s it comes from the Latin Aqua Aqua like aquatic means water and Spanish being a Latin based uh language uh uses the word AA so uh for water all right now uh the next thing we want to address is what is concentration what do we mean by concentration of a solution all right so I I I drew two beakers uh and in this first Beaker we're adding one spoon of let's say sugar to this volume of water and in this other Beaker we're adding three spoons of sugar to the same volume of water so obviously if we put three spoons of sugar in this water and only one spoon in this water would everybody say that this has a higher concentration of sugar yeah so what is the definition of concentration concentration is the amount of solute the amount of solute dissolved in a specific volume of liquid it's the amount of solute the amount of sugar or the amount of salt the amount of protein the amount of whatever I've dissolved in a specific volume of liquid that's called concentration everybody got that yeah how about now yes okay so now the next thing we want to look at is what do we mean by percent concentration there are different ways of quantifying of numerically using a number to express the concentration in other words we don't just say we don't put three spoons of sugar in water and we don't just say it's more concentrated we should be able to quantify how concentrated is it one of the ways that we express quantitatively mathematically it's not it's not complicated uh the amount the actual concentration is called percent now that percent sign should be very familiar if you're a business major you use percents in terms of interest rates and so on uh uh in this case the percent sign percent or percentile always always always means per 100 no matter how you use that percent sign it means per 100 percentile Cent isn't 100 cents in a dollar percent so um uh in this case when we use the percent sign in terms of concentration of a substance in a solution it's grams of solute per 100 milliliters of water you can see we're now using metric system right so what's an example of this so I'm given you two examples so we have something we might run into something called a 5% glucose solution glucose is a sugar now I might just mention that another name for glucose is dextrose usually in biology classes we call it glucose interestingly in hospitals they refer to it as dextrose there's a reason why technically it's the de isomer form of glucose the dextr form but uh so the 5% glucose so what does 5% mean well what did we say per means we said percent means gr per 100 milliliters so can everybody see I wrote in red right GRS per 100 milliliters that's where the percent sign was and then what did I write here five and glucose everybody see what I did so literally there's five glucose and what's the percent mean grams per 100 Millers five grams of glucose for 100 m of water now you might say why why are we mentioning this I mean who who cares you're making my life miserable this is the most common solution used in the hospital everybody see what it says 5% extras all right and then uh another solution that's commonly used in the hospital and the reason why I've got these is I think many of you know I teach physiology and pharmacology that's actually what I do most of my time uh I only teach one biology class uh one Biology lecture each semester and I only teach one biology lab once a year so I don't really teach biology much but anyhow um the uh uh another example is a 0.9% salt solution na ACL that's the second most common solution used in a hospital setting uh salt when we use salt we call it saline what do you how do you say salty in Spanish Sal so uh so it's called a 9% saline solution or normal saline and uh so I'm not giving you this number because I think it's hard you know it's simply the actual concentration of salt Solution that's used clinically I didn't bring the bags with me I've got bags and solutions of all these things so what's a 0.9% salt solution uh 09 grams of salt per 100 Millers of water so we're just trying to explain what these mean uh because uh again this is an introduction to biology and there's a few people in this class who were taking this class because they actually plan to take courses in anatomy and micro physiology anybody here raise your hands so there are people who are taking this to prepare them for those uh Moree uh uh prerequisite courses for the clinical Fields but no matter even if you're not doing that which most of you aren't uh unfortunately I can predict with absolute 100% accuracy unfortunately all of us will end up in the hospital all right and you should know what's going on and one of the things that makes hospitals and doctors scary is that most people have no clue as to what's going on it's a very scary environment and they don't explain a lot and then when they explain it most people don't understand what they just said so part of what we're learning is to help us so that in our in the course of Our Lives whether it's our own lives or the lives of our relatives our parents our children our friends when we have to do with medical issues we will have some knowledge about what's they're talking about as doctors and nurses and Pharmacists and so on this is just a matter of time before you have to know what they're dealing with and we've just explained a little bit what cancer is today so all of this is important because it is part of the reality of life is dealing with disease illness and eventually death so I hate to be morbid but that's why all right so uh now the next thing we wanted to mention uh is what is diffusion all right now these some of these topics you're going to hear more about in lecture as well so what is diffusion diffusion is the name we give uh for the spontaneous movement of a solute from an area of higher concentration to an area of lower concentration yeah if anybody needs paper there's some more paper up here just just have piece of paper to write on again it's all in the it's all in the lab manual but I want to just lay it out step by step rather than just highlighting these words all right so what is diffusion it's the spontaneous movement you'd say what's spontaneous it just like happens on its own the movement of a solute you'd say what's a solute sugar salt anything oxygen from an area of high concentration to an area of lower concentration or in other words diffusion is when something moves down a concentration gradient from an area of higher to lower concentration so uh what what I what I have drawn here is I put a bunch of dots you'd say is that what you did so these just uh these just represent uh either these could be sugar molecules these these could be oxygen molecules this could be any chemical substance and what we see is that if we had a whole bunch of some chemical right here it will spontaneously turn start to spread it will do that on its own and this spontaneous spreading out as it moves from an area where there's a lot of it to an area where there's less this outward spread is called diffusion give you a couple of quick examples if uh if I had a beaker of water and I dropped some blue dye into the water we would see the blue dye start to spread or diffuse until eventually that blue dye would spread evenly equally everywhere in the water that's called diffusion another example if you had if I had a bottle of perfume so there's a high concentration of perfume molecules in this perfume in the bottle if I take the cap off the bottle of perfume what's the perfume going to spontaneously start to do it's going to start to uh waft up and spread out of the bottle isn't it and soon we're going to start smelling that perfume in the air everywhere because that perfume is spontaneously on its own diffusing out of the bottle where there's a high concentration and spreading outwards throughout the air that's called diffusion it's a spontaneous process say diffusion always go towards everything being equal yes will continue to spread until there's no longer a concentration gradient or concentration difference so until that happens it keeps spreading so with that bottle of perfume the more every single hour you'll notice that Snell is getting more intense as more and more perfume is spreading out of the bottle and spreading more and more into the air okay so and it will continue basically until it's totally equalized the concentration everywhere now um let's do one more here what does a cell membrane look like now this is something that you'll be hearing about uh in a lecture if you haven't already what's a cell membrane look like so what I've drawn here all right so case you say what did you just you move that through that quickly I wrote what number five you know what does the cell membrane look like so everybody got that so in our picture so I drew a cell this is the cell membrane right here's the nucleus right typical animal cell could be human sheet cell and uh we we've learned today that the cytoplasm this jelly like fluid on the inside of every cell is about 80% water on the inside and uh all living cells have to be surrounded by fluid we have pointed out that if you're looking at any living cells you got to put water on the slide otherwise it'll die uh so all living things have to live in a fluid environment and so uh this fluid uh this fluid on the outside of the cell is known as extracellular fluid extracellular means on the outside of the cell now in us this extracellular fluid in humans is commonly called tissue fluid so let's let's let me pose a couple of questions here first off um on the surface of your SK skin is your skin made up of cells yes yes it's made up of cells so you might say but I don't feel any water here Professor P you said uh don't cells you said all living cells have to be surrounded by water water I did are these cells on the surface of your skin alive no no they're all dead and one of the reasons why they're all dead is because they're in contact with air they can't continue living if they're exposed to air if you've ever scraped your skin which we all have scraped your knee scraped your elbow scraped your arm you've scraped off some of those dead cells you ever see a clear fluid start to ooze that means you've reached the layer of living cells when you see that clear fluid oozing that's that tissue fluid that's surrounding your living cells when you open up somebody's abdomen and spread it open there's all this fluid around all the organs so all living cells have to be surrounded by fluid or they will die and these are dead because they're in contact with air not fluid now the fluid really in order to keep human cells alive should also be the same concentration of water on the outside of the cell as on the inside so if the inside of the cell is 80% water the outside of the cell should similarly be 80% water so uh now in terms of what cell membranes look like let let me just uh pass out one thing to you and this is something that the subject I'm covering right now I can guarantee you with 100% certainty just like 100% certainty I predicted unfortunately Hospital issues with 100% certainty in your lecture class you will learn in much more detail what I'm about to cover right now and you may have you got cell membranes in Dr Morrison's class yet yeah so yesterday good so okay now I'm not going to get into as much now is your lecture teacher will so what we're looking at is we are looking at the molecular structure of a cell membrane so this is a cell membrane right this is the cell membrane and the cell membrane is basically made up of two types uh two types of molecules largely uh it is made up of a double layer of what are called phospholipids and I said double layer they sometimes call that a by layer of phospholipids you'd say is it say that somewhere right over here it says by molecular layer of lipid now lipid means fat so there's a double layer of fat molecules now the type of fat this is is called a phospholipid lipid means fat it's a special type of fat called a phospholipid and everybody knows lipid means fat because you've heard of lipos suction now there's a double layer you'll notice there's an inner layer and an outer layer now just having fun coloring okay there's a double layer of phospholipids now each phospholipid uh kind of looks like if I just kind of make an enlarged view of one of these guys they kind of look like a balloon to me they look kind of like a balloon with two strings everybody see that that's kind of what a phospholipid looks like all right so each balloon right has two strings attached to it it looks like this it's called a phospholipid now the balloon part interestingly is attracted to water the balloon part of the phospholipid is attracted to water we say it's hydrophilic Hydro means anybody know water and filic means to like so the balloon part likes water the two strings the two two strings on the other hand are hydrophobic they hate water phobic means they hate so we actually every phospholipid molecule is schizophrenic a schizophrenic molecule now do everybody got that hydrophilic and hydrophobic now uh you'll notice there uh if this is the cell membrane the cytoplasm on the inside of the cell is here this is the cytoplasm and the cytoplasm is 80% water so this is this jelly like fluid or water on the inside of the cell and you will notice therefore that the balloon part uh the part of the inner layer of phospholipids that likes water the balloon part is facing the water on the inside the cell now you'll notice there's an outer layer of phospholipid isn't there there's an outer layer and they're upside down compared to the inner layer so the balloon part of the outer layer phospholipids is facing the tissue fluid on the outside of the cell this would be the tissue fluid on the outside of the cell can everybody visualize that so these d double layer or by layer of phospholipids the balloon part that likes water always faces water whether it's the water on the inside now we've talked about diffusion uh earlier today we said diffusion is this spontaneous movement of chemicals from an area where there's more of them to an area where there's less now we're asking the question what are the four factors obviously there must be four that affect the great how quickly these chemicals diffuse specifically through a cell membrane through a cell membrane so the first factor that affects how quickly a chemical will diffuse diffuse in general and specifically diffus through a cell membrane is temperature temperature increasing heat makes everything speed up the warmer you make this things the faster atoms and molecules move this is actually known as kinetic energy so anytime you want to speed something up you increase heat anybody who takes a regular chemistry course learns all about how the way you make any chemical reaction occur faster is you warm it up and that just makes atoms and molecules vibrate and move faster and faster incidentally if heat makes things move faster and faster atom and molecules move faster and FAS faster then cooling things down makes them move slower and slower and if you're wondering like how cold would you have to make it to stop the all movement all movement of atoms and molecules and you actually have to cool it down to a temperature known as absolute zero which is known which is actually minus 273 degrees centigrade and when you cool things down to that temperature which has been done all Atomic and molecular motion stops that's called absolute zero anyhow so uh temperature we'll get to what the next thing is so uh all that I indicated is an example of chemicals that diffuse across the cell membrane pretty easily our oxygen tends to diffuse in why because cells use oxygen and in lecture you either have learned or will be learning that cells use oxygen for something called cellular respiration and in cellular respiration the cells use up oxygen they produce a waste product called CO2 carbon dioxide so oxygen has to diffuse into the cell across that cell membrane and carbon dioxide has to diffuse out of the cell across that cell membrane the warmer it gets the faster those chemicals zip in or out of the across that cell membrane uh now just as an example of what I'm talking about there are organisms that are said to be com the common expression is coldblooded or warm-blooded the better term is really pmic or homeothermic but we'll use those terms cold blooded and warm-blooded we are an example of a warm-blooded organism how warm are we our body temperature normally is about 98.6 degrees Fahrenheit that's almost 100° we're almost 100° our body temperature which is a lot warmer than this air temperature this room temperature in this room is probably about 70 so we're almost 30° warmer than the air temperature an example of an organism that's commonly said to be quote cold blooded would be a snail okay its body temperature is not almost 100 degrees all right think about how that affects the rate at which oxygen enters the cells of our body versus the rate at which oxygen enters the cells of a snail's body you think that might have some effect as far as how quickly the chemical reactions occur and how fast it moves and everything else so uh and if we started cooling your body temperature down you'd start moving and thinking and everything else would be slowing down and as the temperature rises it starts to speed up so that affects the rate at which chemicals go in and out of the cell and chemical reactions now a second factor that affects the rate at which chemicals diffuse in or out of the cell is the difference in concentration between the inside and outside of the cell we wrote that the bigger the difference in concentration the faster the rate of diffusion you'd say what do you mean so I drew pictures of two cells You' say can you make it smaller so I can read it okay right so I drew pictures of two cells in both cases I put a bunch of chemicals on the outside in the top picture there are no none of that chemical on the inside in the lower picture there's already some of the chemical on the inside so the question is in which case the top or the bottom example where would the chemical move faster into that cell the top because the bigger the difference in concentration the faster the rate of diffusion and when the difference in concentration is not as great the rate of which it fuses is slower so the bigger the difference and therefore in the example I gave you earlier today of opening up a bottle of perfume so initially all the perfume molecules are in the bottle and there are zero perfume molecules in the air so it tends to diffuse very rapidly as more and more perfume molecules start to accumulate in the air the rate at which these mole perfume molecules are diffusing out of the bottle of perfume will start to slow down that make sense so the rate of diffusion is related to the difference in the concentration gradient everybody all right on that yep now remember do I did I put on my website various resources to help you understand this the answer is yes it's your choice whether you use them okay now on uh let's we've given you two factors a third Factor this is very simple this is intuitive everybody will understand this a third factor that affects how quickly a chem moves across the cell membrane that diffuses uh is the size of the molecule the smaller the molecule the faster the rate of diffusion so let's imagine two molecules an oxygen and a glucose oxygen is two atoms big O2 even people have me for lecture we've talked at least about an oxygen molecule all right glucose is 24 atoms big C6 h126 it's got 24 atoms making up that molecule all right so I tried to draw them proportionally that this one's smaller that one's bigger so which one gets across the cell membrane faster that's obviously the small one does in fact if the molecule gets too big won't be able to get across cell membrane at all obviously when I drew these in real reality ules are not that big compared to a cell but if if I drw them relative to the size of the cell they'd be too small for you to see either one of them all right and the fourth and last factor that affects the rate of diffusion whether the chemical the next question that we want to take a look at is what is osmosis what is osmosis uh osmosis is simply as I wrote the diffusion of water either into the cell or out of the cell whenever water flows through that cell membrane that's called osmosis uh why do we give a special name for osmosis or for the diffusion of water calling it osmosis uh for all the other substances we just call it diffusion when oxygen diffuses into the cell or carbon dioxide diffuses out of the cell down its concentration gradient I guess the reason why a special name is given to when water diffuses uh is because water is really the only liquid that we commonly talk about uh at least in a biological or medical sense all the other substances that are flowing or diffusing into a cell or out of the cell are either solids or gases and and water is really the only liquid so when uh this liquid water starts to flow in or out of a cell we give it a special name osmosis now of course uh water can flow either in or out but if a whole lot of water were to start to flow into the cell that could cause the cell to swell up with water even to the point where it might burst uh on the other hand if a whole lot of water were to flow out of the cell then the entire cell would collapse it would basically uh implode and uh uh collapse that's actually as we'll see known as crenation now the last uh topic that we want to address here is the question of tonicity now you actually have a picture showing uh a an analysis of tonicity on page E6 uh in the lab manual this is actually page E6 and on E6 it shows uh what happens when a cell uh is placed in what's known as an isotonic solution a hypotonic solution or a hyperonic solution solution um you can look at these pictures but let's take a look at a picture that I've drawn here uh and we'll use this to help explain it so what is uh tonicity so in the a first of these uh test tubes it shows a cell it happens to be a red blood cell but it really doesn't matter and uh it shows uh the uh red blood cell where we are reminded that in all cells uh the inside of the cell the cytoplasm is about 80% water and 20% other stuff by weight and that other stuff would include proteins and sugars and vitamins and minerals and so on so we've represented this other stuff or solutes uh by dots now if that cell is placed in a solution that is similarly a % water and 20% other stuff other solutes that solution would be called an isotonic solution ISO is a Greek root that means same equal atonic means strength so so it's the same strength the same proportion of solutes and water in the fluid outside the cell as inside the cell and obviously this is a happy cell because there's not a uh there's no concentration gradient for water to either rush into the cell or rush out of the cell so the cell remains a constant volume it neither swells up and uh bursts nor does it collapse now two examples of solutions commonly used in medicine uh that are isotonic are a 5% glucose solution and a0 9% salt solution commonly called a saline solution now one when I mention these as isotonic Solutions uh one question that might come to mind is well why aren't they the same number why is a 5% glucose solution uh uh isotonic and same with a 0.9% salt solution so I want to remind you that a glucose molecule is a much larger molecule and weighs more than a salt molecule which is much smaller and weighs less so in other words one molecule of glucose would weigh more than one molecule of salt so in fact five gram of glucose actually has the same number of molecules in it as 9/10 of a gram of salt in other words imagine if you had 100 glucose molecules and 100 salt molecules wouldn't the 100 glucose molecules weigh more because each glucose is a larger molecule so these two five gram of glucose in 100 Millers of water or 9/10 of a gram of salt in 100 Mill of water actually contain the exact same number of solute particles or dots so those are both uh isotonic Solutions now in the second test tube uh it shows that uh the cell uh which is still 80% water uh inside the cell and 20% other stuff is in this case placed in a 100% water water solution now A solution that has a lower amount of solute than uh than is found inside the cell was called a hypo tonic solution hypo means low and tonic means strength so it's low in solute it's low in salt it's low in sugar it's low in protein and in fact in this case it's all water so it's a 100% water now obviously if it's 100% water on the outside of the cell and 80% water in the inside of the cell uh you should be able to see that there's a concentration gradient for water there's a higher concentration of water outside than inside so what is water going to do it's going to diffuse down its concentration gradient into the cell remember the anytime water does diffuse either in or out of a cell that's called osmosis so osmosis is going to occur and as the water flows into the cell the cell is going to swell up larger and larger and larger and at a certain point it will burst and so that uh when a cell ruptures or breaks apart we use that Greek root lysis which means literally to break apart so that's not a very happy cell that's a dead cell now as a pneumonic or memory a uh to remember what a hypotonic solution is hypo has that very prominent o in the center it's high in H2O a lot of water and as the water flows into the cell the cell will swell up like a hippo okay it's not the really the way we spell hippo but if it helps you visualize uh what happens when you place a cell in a hypotonic solution it would swell up incidentally any sugar solution with less sugar than five grams uh of sugar and 100 Millers of water uh would be a hypotonic sugar solution and any salt solution with less than 9/10 of a gram of salt in 100 m of water would be a hypotonic salt or saline solution now the third possibility is to surround the cell in a very concentrated so-called hyperonic solution hyper means High antonic means strength it's high in solute it's got a lot lot of sugar or a lot of salt or a lot of protein or a combination of all those things but it's low in water it's all solute it's hypertonic high in solute now in this example we've uh given here if the uh fluid if the hyperonic solution is 80% solute and only 20% water remember the inside of a cell is normally 80 % water so if it's 80% water on the inside of the cell and only 20% water on the outside can you see that there is a higher proportion of water actually inside the cell than outside in terms of the proportion of water and solute so water is going to flow down its concentration gradient flowing from a higher concentration of water to a lower concentration of water as the water flows out of the cell again that's called osmosis and as that water flows out uh the cell is going to shrink in size it's going to collapse as the water flows out of it and as we wrote right here uh this uh as the cell starts to collapse and trible up that's commonly called crenation we say that the cell is becoming crenated and U again uh any sugar solution with more sugar in it than 5% in a glucose 5 gram of glucose in every 100 m of water would be a hypertonic glucose or sugar solution and any salt solution containing more salt than 9/10 of a gram per 100 milliters of water would be a hyperonic salt or saline solution now in fact if you were to uh look at the lab manual on page E7 on E7 are some actual draw drawings and micrographs of cells that are actually being exposed to isotonic hypotonic and hypertonic Solutions so uh on page E7 uh on the uh left uh we have a drawing showing a uh cell uh reminding uh we are reminded that it's 80% water on the inside of the cell normally and if the fluid or solution surrounding that cell is similar 80% water uh and 20% other stuff just like inside the cell that's called an isotonic fluid and this is a happy cell you can see it's smiling and in fact uh here is an actual photo micrograph of red blood cells in an isotonic solution and you can see many of them are smiling as well in the uh in the second drawing in the second drawing uh it shows uh a cell uh 80 % water inside that's normal and in this case it's surrounded by I wrote 90% water it's not 100% water I see some dots surrounding the cell some solute uh but it's mostly it's certainly a higher proportion of water outside the cell than what looks like inside so if it's 90% water on the outside 80% water on the inside that means there's a higher proportion of water outside than inside right so water is going to Simply flow like all chemicals do it will diffuse from an area of higher concentration an area of lower concentration as the water flows into the cell the cell was going to swell up this sh picture shows the cell swelling it's almost at the bursting point and uh and this is called uh this is what happens when a cell's placed in a hypotonic solution and in fact in the photo micrograph of actual cells on the right it shows cells you'll notice they're not smiling they may even be crying because they're about ready to burst or undergo lces as the water continues to flow into them the third possibility is shown in the bottom figure uh the bottom picture it shows a cell again 80% water on the inside that's normal and in this case surrounded by a hypertonic solution one that is higher in solute particles and lower in water and in this example 20% water so again what's water going to do it's going to spontaneously start to flow from an area of higher water concentration to an area of lower down its concentration gradient whenever water flows either in or in this case out of a cell that's called osmosis and as the water flows out of the cell the cell is going to start to collapse to shrivel up to be undergo crenation and in fact here's an actual photo micrograph of red blood cells that do not look happy uh they are uh frowning they are uh collapsing as the water flows out of them all right so that's the concept of tonicity and how the uh proportion of water and solutes in the fluid surrounding the cells how that affects uh the movement of water causing water to flow into the cell or causing water to flow out of the cell