Transcript for:
تعارفی حیاتیات اور MCAT کی تیاری

so let's chat um so I'm gonna start off with a little story about this lecture hall specifically so obviously I went to Brooklyn College and the first class I was ever in when I came to Brooklyn College was an intro bio course and that intro biocourse was taught by Professor mcatee I don't know if she's still here but she's a fantastic Professor I hope that you guys all have the opportunity to cross paths with her but she taught in this lecture hall and that was my first class ever and I was seated right there in like the third to last row and I can remember where I was sitting and I can remember what I was riding on and uh five years later here I am and I'm teaching my own course in this exact lecture hall that I was in my first day of college so that's crazy but hopefully I come with a newfound understanding of how to teach and how to learn and what it means to succeed right it's a lot of MKC my name is Yusuf nice to meet you guys I'll get all your names in a bit but before we do that let's just talk a little bit about you know what are we getting ourselves into what do we necessarily mean when we say like let's study for the npat let's prepare let's get ready to take this big exam so what is the MCAT what does it mean why is it important yeah you guys have seen that ad before the Princeton Review ad right so yeah Dan Hat's hard game that's important but it's not impossible and it never has them so the MCAT is basically just this little holistic knowledge game about how much you know about pre-medical studies and you'll hear a lot of people tell you that pre-med doesn't really matter like it's not the most important thing in the world it's not relevant to medical school that's a load of uh pre-med is probably the most important arsenal of knowledge that you'll ever get in your entire college career other than what you decide to major in because that's ideally what you're passionate about right so I decided to major in philosophy and it's something that I use every single day in the way that I write in the way that I speak in the way that I hold myself and in my further Pursuits in the future but pre-med is your foundational understanding of how to make it in the world of medicine right so when we talk about an exam that tests your entire knowledge of pre-med we obviously need to start at the beginning now here's the thing how do you teach someone and test someone on everything and that they know about pre-medical studies it's almost impossible right it's almost impossible to fit that much information on one exam right which is why that's not what the MCAT is MCAT is a test of application of very very basic principles right it's a test of understanding more than it is memorization which is why when people ask me they're like oh well how much do you need to memorize in medical school it's close to zero because all memorization really only comes from understanding a core principle right so if I'm studying Cardiology which is what we're doing in medical school right now and someone walks up to me and they're like oh well where does the right atrium lead into it leads into the right metronome right and what value does it go to accrue it goes through the tricuspid valve right and that just kind of rolls off my top but it doesn't happen because I've memorized it it happens knowledge of how the heart works I have an interesting knowledge on how it's separated how it's embryologically derived how each and every single part of the heart plays a role in distributing blood throughout the body so before we talk about anything we need to go all the way back to the foundations of science and that's why we're going to start with General biology so if you have MCAT books which I would sincerely hope that you guys have either from you bought them or you got them online because there are online resources which gives you outlines of the book you don't necessarily need the textbooks in front of you General biology is one of these seven or eight textbooks that you get from Kaplan or Princeton or blah blah blah whatever so what is general biology right what is it what's a biology it's the study of Life the study of living things now in preparing for medical school what are these living things that we care about we care about humans we care about bacteria and we care about viruses our virus is living no they're not so they don't get included in living things right so in living things we care about bacteria and we care about viruses but so much of biology overlaps with non-living things that every now and again we talk about things like viruses and prions and things like that right now before we talk about living things as a whole and you know building our understanding up to how does a human physiologically function what are living things made of cells right so that's chapter one chapter one is the sound right chapter one is the cell that's where all of it begins that's where we're all gonna start that's Hi how are you guys we're gonna Mitchell Stewart thanks so much guys this is Mr Stewart It's thanks to him that I was able to come here um thank you so much for having me and thank you for inviting me of course right all right come here okay so chapter one we're going to talk about the cell what the cell is what the cell does blah blah blah blah so this is a general question for the room right and this is what we mean by foundationalizing our understanding of Science and scientific principles who can answer a very very basic question what is a cell what is it has anyone ever asked you the question has the question ever crossed your mind maybe not because sometimes professors who are much more knowledgeable than I am will Overlook these very basic facts in order to get you to information that's actually going to allow you to succeed in their class and in future Graduate Studies if you choose to pursue them but without this knowledge you're not even able to appreciate those Concepts which is why throughout this course you're going to hear me say I am not a professor I am a student and I have a student level knowledge of all of these Concepts that may or may not help you go in the right direction okay I at one point knew as much as you did or as little as you or maybe you know more than me but hopefully you can pick up on one or two things that I'm going to teach here so what's a cell a cell in my definition is a compartmentalized organized um and cortical well-oiled machine that can undergo various life processes it's a machine right it's a little it's a little engine it's a little you know a Little Engine That Could you know what I mean so what do we mean by compartmentalized what is this compartmentalization that I'm talking about yeah so it's split up it's split into split into one split into organelles what's the purpose of having organelles well before we talk about that I'm gonna make a little asterisk here and who knows what I'm going to write onto the asterisk what types of cells have organelles eukaryotic cells only do prokaryotic cells have well-defined and well-structured organelles they do not prokaryotic cells are this weird soupy mishmash of genetic information and life-producing capacity right but there are certain things that every single cell is capable of regardless of how they're defined and we're going to talk about that in a second by organized I mean that each each process occurs in a controlled manner what do I mean by that well when we get to biochemistry we're going to learn about this little molecule this hormone called insulin right and Insulin can react with cells in a very specific way in order to increase glucose uptake and increase glucose you know uh breakdown and synthesis and blah blah blah but it also so it positively affects a lot of glucose metabolism also I know my handwriting is fantastic if you need me to read something out please let me know it pro affects a lot of glucose metabolism but it also negatively affects fatty acid breakdown right and that's a really interesting thing that we're going to talk about called positive and negative feedback and basically all of your life processes run on this sort of foundational understanding of positive and negative feedback mechanisms right where something is affecting this in a positive way and pushing it forward and something is affecting this in a negative way of pushing it back right we were just talking about this when we were studying Cardiology right where your heart if you didn't know it would like to beat at 140 to 160 beats per minute for your whole life however due to a constant level of Regulation by your parasympathetic nervous system it beats at roughly 60 to 100 beats per minute right and that is called negative feedback or negative control correct so there's a sort of inhibitory process that occurs to organize those processes inside of your body so that you don't blow up right so they don't die right and what do you mean by well-oiled everything happens in a fluid manner one thing leads into the next leads into the next lead to the next so when we talk about compartmentalization and we talk a little bit about you know how things are split up and blah blah blah blah you're going to hear me talk a lot about well this thing leads into that one and that leads into that one and that leads to that one and then finally you get a result where DNA is in the nucleus and then you can turn into mRNA and the MRNA exits the nucleus and then it goes into the rough ER we just started with ribosomes the ribosomes turn into a protein and the protein goes to the Golgi apparatus where it gets modified and packaged and turned into a vegetable that vesicle travels through the cell merges with the membrane and it's exported out do you see how one thing led to the next and led to the next and led to the next that is the well-oiled nature of a cell does that make sense very cool all right so I think shrimp I didn't bring anything to a racist with so don't judge me or he's a massive those don't work see how much better that is I had a professor back in the day he's the greatest Professor I've ever had in my entire life and there's no competition his name is Professor Lenny bitlitsky if you guys ever have the chance of coming across him he's quite literally like the worst person in the world but the best for your education he didn't go to Florida I have his phone number I spoke to him the other day he knows that I'm doing this so he's kind of the person who inspired me to do this in the first place so russellitski he always looked like he was erasing the board with his hand but right in like the palm of his hand he has this tiny tiny piece of tissue paper and that's what he would use to erase all this stuff now when I started teaching and I put a whiteboard up in my room and I had a little tripod like this I was teaching I tried using those erasers and they just didn't do the trick so I was like this man must have been up to something so I took a little piece of uh a little piece of toilet paper and I put it inside of my hand and I erased it it just like completely the face the board and that's why I do that now shout out to Vladimir let's see what's up uh do you normally sections how many sections like how many how long do you think like the actual course yeah I don't know I really don't know I wish I did I'm like writing up a syllabus now as we speak so I'll probably have an answer for you by like next week Tuesday Thursday I am here from on Tuesday Thursday from six to whenever we get done but never past nine does that make sense so today we're probably going to cover like the first two chapters of biology right my laptop's charging over there because I need that to teach and my charger gave out on me which is one of the unfortunate things that happened today but I'm using a different charger that I have it's just charging really slowly so we're going to teach a little bit of the stuff that I remember before we look at my laptop with the rest of the information so we talked a little bit about like what cells are in my definition right but now let's dive into the textbook and see what the textbook has to say about cells and the first thing that the textbook says about cells is this blanket statement called cell theory let's talk about cell theory it doesn't sound like this uh character from Dragon Ball Z or something yeah let's talk about not that guy but let's talk about salary so cell theory has four components number one being like one of the first things that we actually said when we came in here so number one being all living things are composed of say with me cells all living things are composed of cells so anything that's living is made of cells right that's quite basic basic knowledge right let's look at number two so are the functional unit of life now I use a lot of short hair when I write because it just makes things faster so whenever I are functional I go like this that means function and that's an Al functional right the cell is a functional unit of life what do we mean by that what's the difference between statement one and statement two well you can use flour to bake bread right but it didn't all come from the flower something was turned into the flower right so all living things are composed of cells is like Bread is made of flour but cells are the functional unit of life that's saying that flour is the functional unit of bread but there are other things that compose those cells meaning there's other things that make the flower right so it's not that the flower was just there and then made the bread so the cells were not just there and made the life that's what we're saying right what we're saying is there there was something in between that came together into the cell and then the cells became the functional unit of life and then the cells are now what makes up all life correct cool so what's number three I still remember so oh cool cells form pre-existing cells right cells form from pre-existing cells Elena what the hell are you laughing at number four cells carry genetic info that they passed down onto the dollar cells what are we talking about here and what are we talking about here so asexual and sexual reproduction both right so what we mean by saying the Korean State before so this is kind of confusing and the reason you really want to get a good grasp on this is because the MCAT does kind of ask about it every now and again where they're like oh well if this were to happen What rule of cell theory is being violated here or like how do viruses not apply to cell theory which is something we're going to talk about in a second right so cells form from pre-existing cells well we have a cell and a cell buds off of it and becomes whatever it is right but if that cell doesn't have genetic info it can't do the same thing right or it can't code for a protein that it needs or it can't code for some sort of hormone or some sort of blah blah blah whatever it is right so we need that genetic info to be passed on when the cell arises from a pre-existing cell because this statement doesn't mean anything to us if the viability factor which is the genetic information is it passed on as well does that make sense so what we're talking about is we have a cell and it's made up of a bunch of stuff and somewhere in that cell inside of the nucleus we have genetic info that gets passed on to a daughter cell in one way or another and if there's an equal division it's called mitosis and if there's an unequal division it's called meiosis correct guys by the way if you ever need to leave if you need to walk out if you want to eat here if you want to do do whatever the hell you want at the end of the day if there's no one here it's going to be me talking to a camera all right so don't feel bad about leaving or coming in late okay cool so this gives us mitosis slash meiosis and this gives us organelle Theory right and those are the two main things that we're going to talk about for the rest of the chapter so the one thing that a lot of people are saying is they're like oh will they bring up cell theory and then they just never talk about it again they do they're just not telling you that they are because the rest of the chapter is elaborating on cell theory so while you guys write that down I'm going to check to see if I'm locked possible it is that's good I'm gonna leave it here and you're gonna see me walk away and if I'm walking away I'm not ignoring you I promise right so let's talk about now that we know this right do you guys have a solid grasp on that yes if I'm going too slow or too fast please let me know and if I'm saying something that you already know or something that's obviously like you know you already know it you would have been like eighth grade please tell me to shut the up and like move on right okay okay so let's talk about our first question I just bought this marker here let's talk about our first question what makes viruses not alive so we talk about we talk about eukaryotes talk about prokaryotes we're talking about viruses right okay so I saw a hand up there a little bit of projection yeah yeah so viruses number one they can't reproduce and I like that you said like sells can because clearly viruses have made it this far right and they can reproduce and we saw a really good example of that three years ago right so clearly viruses are capable of reproduction but what do they need in order to reproduce they need a host they need to sell they need something living to do the work for them because viruses don't have ribosomes and viruses don't have nuclei and viruses don't have golgi apparatuses and viruses don't have peroxisomes and they don't have like cytoplasm things like that they're just creepy crawly bundles of genetic information that's it and it kind of poses an ethical dilemma like if that's not alive but it can proliferate like why is it not alive why is this our definition of what alive is what it is right so whatever what else what makes viruses not alive so viruses don't form breezes and cells and the second thing is they don't pass on to daughter viruses right they don't pass on to other viruses what do viruses do in order to reproduce we're going to talk about this later in the chapter if you guys don't know but what do they do to reproduce they take their genetic information and inject it into a host a cell right and that cell because it's programmed to do so takes the genetic information runs it through the machine and reproduces these proteins and miraculously because of beautiful chemical interactions the proteins reassemble and it either lays dormant inside the cell or it blows out of the cell and transports itself throughout the body any questions about that those two things that I said before it either lies dormant or blows up the cell and leaves those are the two things known as what they're two types of Cycles the lytic and the lysogenic cycle we're going to talk about that a little bit when we get into viruses but the existence of the lytic and lysogenic or lysogenic cycle is more indication that viruses are not living things does that make sense yes good let's have a short discussion a very short discussion about eukaryotes and prokaryotes okay what's the first statement to put up there sorry exactly the way that there or you can feel free to come come down how are you come sit so this one has membrane-bound organelles this one's basically just one big organelle right so whereas eukaryotes use the mitochondria and the inner membrane of the mitochondria and like the mitochondrial Matrix and the intra the intramembrane whatever I forgot what it's called like a blanking on the word um at the age remembering space right so whereas you know eukaryotes use that in order to power the electron transport chain the citric acid cycle blah blah blah what do prokaryotes do they just use their membrane they just use the membrane in order to produce energy produce ATP and undergo all those processes that we do this brings up a really interesting theory that we're going to talk about in a little bit and gold star to anyone who knows the name of the theory what is the theory of this sort of merging of prokaryotic eukaryotic sort of cells way back in time hundreds of millions of years ago endosymbiotic Theory endosymbiotic here is a really really important thing inside of the sort of foundation of cellular and molecular biology can you tell me what another symbiotic theory is so you're absolutely right right you're absolutely right in the fact that a cell ate another cell and that kind of became an organelle and that organelle was the mitochondria right so there was a cell that was already producing its own energy and another cell came along and engulfed that cell and created a environment within which that cell could undergo all of its energy making processes in a controlled Manner and for the benefit of the other cell it's almost like a parasite right but this parasite is giving you energy and you're feeding in nutrients right so interesting thing is that all of these people in this room right and all of the mitochondria that we have in all of our bodies how many trillions who knows right where they all come from one person one single the first female human ever produced every single mitochondria in this room because mitochondrial inheritance is through the mother and I would write that down if I were you because it's a very very hot MCAT fact whenever you see the words mitochondrial disease on the MCAT you can bet your sweet ass they're going to ask you where you got it from every single mitochondrial disease is inherited from the mother that's not to say that it's x-layed those are different things but you inherit a mitochondrial disease from your mother because you get your mitochondria from your mother why how why can't you get your mitochondria from your father yeah the sperm doesn't have one it doesn't have a mitochondria it's not capable of producing that level of energy by itself the egg cell is so much larger than the sperm that it carries almost all of the thing the sort of material that becomes the embryo right so maybe one percent of whatever's left comes from the sperm but but what does come is half of all of the genetic information right is contained in that one percent of information all right all right so what else about prokaryotes well they're single cell right like bacteria H pylori E coli right Clostridium difficile you're all single-celled organisms right and they've evolved in different ways to have different effects on the human body and that's how they survive right so let's talk about mycobacterial tuberculosis which causes what do you think it causes tuberculosis right so it infects the human body and it causes you to cough and sneeze a blah blah and you pass it on to another human being and they replicate their body and cough and you give it to someone else and that's how they survive if it all happened together one cell and since they're single celled it's a lot easier for them to reproduce What do humans need to do to reproduce rhetorical question right we'll get there later the next chapter is actually reproduction and I don't know how far we're going to get into like that chapter because in reproduction if you guys are like reading the textbook before you come here which you don't have to do all my lectures are made so you don't need to study at all before you come to them which is why we're going really slow but I'd rather go like this than overstep and not cover something that someone hasn't read before right so when you get to chapter two you're gonna get smacked across the face with this very long page about the menstrual cycle and it's really damn difficult to understand because there's like five different hormones at play and different levels and different things going on blah blah they're gonna say Tropic and not Tropic and downstream effects and positive and negative feedback mechanisms of the hypothalamus you're like what the hell is the hypothalamus because I never explain it to you I'll teach you that's what I'm here for okay so that you don't cry at your desk like I did when I read that page right okay cool so single cell right and another thing here is what no membrane bound organelles no membrane noun orphanals right so and then eukaryotes very specific wording here by the textbook not by me it's 10. be multicellular can can be a multicellular what's an example of a unicellular eukaryote huh protozo I think that toes the line between both of them right what else an egg cell um I don't know if that qualifies an organism it's just like a cell right but yeah that's a eukaryotic cell for sure because I remember about yeah I would say that okay I think yeast I think yeast kind of organelles if I'm not mistaken right those are single cells correct okay and honestly that is really all you need to know about prokaryotes and eukaryotes that's that's like it that's the basic level of knowledge you would need to perform well in the MCAT right now doubling back on what I'm doing here and like why I'm spending my time doing this right like I said before I'm here to teach you how to do omnium cat right but I don't really care if you don't do well on the MCAT because I have friends in medical school who didn't do well in America who personally did pretty poorly on the MCAT like got below an 80th percentile and still study with me in the same rooms and in the same lecture halls and take the same tests and do just as well as I do because the one thing I want to say from the start is that this exam will never Define your success as a medical student or a physician ever it will never determine who you are the only thing that I'm here to do is give you a foundational understanding and appreciation and passion for the information that goes on this board because if you genuinely care you'll do well let me tell you a little bit about my story so I started studying for the MCAT in January of 2021. it was a really bad time in the world I was locked up at home not coming back for you know my next semester blah blah whatever it is and I was pretty lonely to be completely honest I wasn't hanging out with friends I didn't see my family all that often because they were either at work or coming back in blah blah some people my family got sick and then I had my wisdom teeth removed and I had to take like two weeks off of studying because I was in a lot of pain blah blah and I thought it was just the end of the world right but the MCAT gave me something to look forward to it gave me some form of Solace from the noise that was going around me and I became so passionate and so head first driven into everything that I was studying that I genuinely gave a I actually cared and if you didn't care about anything you were learning before which is fine I beg you to try to care now and the way that I developed a care in the world was by studying every single day they say that once you do something enough you learn to appreciate it regardless of where you first started so once I hit the 100th 150th 200 300 400 500 hour of studying for one exam I had a deep respect for the information that I'm giving you now and that's why I'm able to relay it in a way that matters because I have a love for the things that I've learned and it developed because I gave a and that's all you need that's all you need to do well the people who didn't do well on the MCAT why are they in medical school because they gave a they cared they're some of the most passionate people I've ever met in my entire life what score did I get on the MCAT I got a 98 percentile score there are people at my school who got in the 78 80th percentile who I will always say to the day I die that are smarter and more passionate than I am because they care more than I do and they have more passion and they have more Drive than I do so when you study for this test care genuinely put your head down and Care like you never have before because you can and you have the time to do so and don't tell me that you don't because I'm a second year medical student sitting here taking six hours out of my week to tell you to study for an exam that you're gonna take so don't point fingers at me and say you don't have time because if I do then you do too so let's keep talking what is cytosol what is cytosol and how is it different than cytoplasm I genuinely don't know if you're correct or not I forgot but I believe that cytoplasm is like the whole thing I think so right and inside is all the flu right so whatever fluid whatever goes in that food whatever blah blah blah like albumin different proteins and vitamins and little ions and whatever is floating around inside your cell that's holding up all the organelles and suspending them inside the cell that is what we're talking about right now what's in there what floats inside of there what is sort of this mishmash of stuff that holds ourselves together right well the biggest thing and it's probably the most important thing that it's holding is a little something known as the nucleus and this is cell HQ right this is cell HQ right so in the textbook they say control center of the cell right and it's surrounded by a double membrane and whatever something surrounded by a double membrane you bet your ass it's important right what exists inside of that membrane right so let's say we draw a little thing right here right and then we have all of this DNA and why do I draw it all bunched up like that well that's how it's compacted and stuff like that we'll talk about why it's compacted that way and how it's compacted that way and blah blah blah right by the way heterochromatin or U chromatin people who've taken the exam hetero yeah are you sure about that one yeah so we'll talk about heterochromatin and we'll talk about U chromatin we'll talk about why DNA is wrapped that way right and we'll talk about histones right and I'm just giving you a little glance of what we're going to talk about in a little bit but if we have this double envelope right here what exists in the envelope in order to allow the smallest bit of communication with the outside world pores there exists nuclear pores and this is how things get in and outside of the nucleus by the way for anyone who walked in late I have a bit of a sinus infection I'm sorry if I've been congested um there's this nuclear pores in order for things to get in and out of the nucleus right and their pores in and out of the new it's cool makes sense right the DNA it's sort of you know compressed into this sort of tightly wound structure around what so we have obviously linear DNA and of course it's double stranded right I'm not going to take my time to draw a perfect double strand that's a waste of time right with a double stranded it comes linear and we wrap it around something what do we wrap it around this gets wrapped around histone proteins have you guys ever heard the phrase that DNA is negative yeah yeah like anyone DNA is negative what's negative about DNA is it just like sad all the time no where I can't see it doesn't exist yeah I'm just pulling your leg all right so DNA and we'll get more into this when we get into biochem and I can actually draw it out for you but DNA has a bunch of these bases right out of those bases on the edge we have these phosphate groups and phosphate group I'll always draw as po42 minus right and that doesn't seem like it makes sense because normally when you think of phosphate inside of General chemistry you're in the po4 3 minus right because that's just the normal charge that a phosphate has because we talk about phosphates we're talking about this in general chemistry so if you're talking about like sodium phosphate it's three sodiums connected to that why is it two minus in the body and pre-minus in chemistry well the body is held at a certain pH right and at that pH one of these sites is protonated so it's hpo42 minus but there's no hydrogen attached to it the carbon backbone of DNA is attaching to the phosphate so it goes like this and that R Group is the DNA does that make sense so when that R Group attaches to phosphate you can see that the terminal end of the terminal n terminal means n the terminal of the molecule right is negative there are negative charges that are very scary word resonating here right there's a resonance that occurs and if you guys don't know what resonance is we'll get into it we talk about orgo right but there is a sort of sharing of this negative charge that occurs over the terminal of the molecule and that creates a negative terminal how do you get a negative thing to attach to something bring a positive thing near it right so if I take a negative terminal of a magnet and a positive terminal magnet and I throw them in the air they're going to snap together and come back down and it's going to be quite hard to pull them apart at their strong magnets think of histone proteins like the strongest magnet you've ever seen in your entire goddamn life it's a little ball right and they're made up of little subunits that you don't need to know even though the book says you have to you'll never need to know them I don't even know them in medical school right but it's called histone why is it called histone Elena why is it called a histone anyone know why it's called a histone the way you're gonna remember this I actually don't remember the specific amino acid right I think it's histidine but it could also be lysine that the histone protein is made up of amino acids that have what type of R groups positively charge our groups positively charged R groups if this is all a bunch of gibberish to you write it down and we'll talk about it when we get to biocat that histone proteins are constructive of amino acids AAS we're not using Capital A's because we're not alcoholics right not Alcoholics Anonymous that have positive positively charged R groups right so if they have positively charged R groups and the histones are made of those amino acids the histone proteins are positive and if the histone proteins are positive and they're these little balls like this and the DNA is linear sections of the DNA can use their backbones to coil around and attach to the histone proteins and that's how we wrap them around those histone proteins and get it completely tightly packed does that make sense is anyone not following yeah yeah so what happens is that the histone proteins have positive amino acids right either histidine or lysine I'm not 100 sure which one and you'll hear me say that all the time because I don't know everything right you guys can definitely look it up for me that'd be great right because you have to know I don't right so the histones have amino acids which our groups are positive so let's just talk about immunosis for a quick second that's the backbone of an amino acid and this is the R Group that R Group we're saying is positive positive and if that positive R Group is put near the phosphate terminal of a DNA it can wrap around the histone protein because the whole histoprotein becomes positive right okay so when you bring a histone protein when you bring the little ball and I always draw my headstones like this because it shows that it's made up of Parts but what else is that that's a positive side so when the histone ball is brought near the DNA which has these negative groups on it the DNA wraps around the histone protein and gets magnetically an electromagnetically attracted to it okay all right we're gonna fast forward a little bit and I do this all the time I call it over exposure or I don't call it that Professor malinsky calls it that right but I'm going to do exactly what you need I'm going to over expose you to something not covered in the chapter so that's how we make what heterochromatism what does hetero mean hetero means two right two of uh two of two different things heterochromatin is when DNA and histone proteins come together and produce compact DNA heterochromatin is the compact form of DNA does that make sense okay so write that down heterochromatin is the compact form of DNA don't you dare judge me you chromatin would then be the loose form of DNA right so write that down U chroma 10 is the loose or relaxed form again so now we know how to go from regular linear DNA to heterochromatin how do we go from heterochromatin to euchromatin how do we undo that attraction well there has to be a way for what there has to be a way for us to separate those charges right because if we take the positive charge and make it neutral or even better make it negative then they'll repel correct that attraction will be broken let me introduce you to a type of reaction can I erase this let me introduce you to a type of reaction known as an acetylation by the way can someone who has a phone or a laptop look up for me what amino acid makes up histone proteins Arginine license cool those are both positively charged although it's not histidine which would be really helpful because it's called a histone protein okay so arginine lysine right okay so now let's talk about a reaction called histone acetylation what's an acetyl group that's in a subtle group that thing right there that isn't a set of group so for people who haven't taken organic chemistry you can also write it out like this that's in a subtle group right so we're talking about histone acetylase we're doing we're taking this group and the r is the histo right we're taking the histone we're attaching a saddle group to it right good yeah so what we're doing is we're taking those positive amino acids right of the histone they're like positive like this and instead of making them positive which normally is done like this right so let's say this is the rest of the histone this is lysine because lysine it stretches out like this that's the end of Lysine that's the positive part of Lysine now instead of NH3 what we do is we take off one of those Terminals and we attach this a cell group to it and what have we effectively done we even neutralized the charge we have destroyed the potential of this to attract a negative molecule but what was this a part of it was part of the histone protein so when we take the histone and we acetylate it over and over again at all of the different Arginine and lysine terminals we are effectively making the histone neutral we have zeroed out of charge and since it's no longer positive it can no longer attract DNA because DNA is negative and neutral things don't attract negative things they attract nothing neutral things are just neutral right and we're going to talk about all these intermolecular forces when we get to organic chemistry and biocap so this is the little overexposure but the foundational understanding comes from understanding the fact that and if you understand this then good if you don't it's fine the fact that London dispersion forces and dipole induced dipole forces are weaker than ionic attractions right dipole induced dipole is what's going on right here the negative versus the acetyl group or the dipole-dipole right because we can talk about like the induced dipole on the ch3 terminal or we talk about the polar moment of the carbonyl group right here right cool so that's like dipole dipole or dipole induce dipole whatever it is but those are always going to be weaker than ionic attractions which basically just snap two things together does that make sense so now that we've weakened that Bond the DNA is allowed to go free and this is exactly what we do in order to transcribe DNA we loosen up the piece of the DNA that we need it gets red and it snaps back onto the histones after the histones are de-acetylated de-acetylated when the acetylation is undone does that make sense does everyone understand that so now you know because the textbook's not going to tell you but I am you know how DNA gets Unwound for replication because in the back of your mind they're just like oh well the DNA replicates before mitosis which they're going to talk about later in this chapter how how does it happen now you know because I just told you right cool so what were we talking about before does anyone need to remember because I almost don't but I do some other new things nucleus and how those pores and all that DNA hetero or euchromatin hetera right heterochrome cool all right now the nucleolus is this like little dark spot on the nucleus where like rrna synthesized and that's just a fact that in through the textbook every now and again it comes up on like a little image that I point to it what is this and what happens here well all over there all right so we talked about the nucleus and we talked about how DNA gets unwell we talked about how DNA gets wound we talked about like acetylation DSL energy rate reactions we talked about the histone proteins which are really important proteins four DNA winding blah blah blah a lot of information right we're done done with that okay what's next what's the next most important organelle the mitochondria the mitochondria is the Powerhouse in the cell oh my God it's so cool I want to him so bad right mitochondria the mitochondria is where all almost almost all of the effective energy of the cell is produced here's a quick fact for you here's body produces puns of ATP every day right you have to have to right it's why we eat is why we drain like we we do this in order to survive right let's say I ran a marathon you would guess that the majority of the ATP produced in my body at that time was used for muscle contraction correct untrue where's the majority of ATP in the body used that's that's 10 of glucose goes to the brand I know where you're going with that one but this is this fact blew my mind when I thought about it have you guys heard of sodium potassium pumps greater than 50 percent of your ATP that your body will ever produce is used by those pumps in order to maintain membrane potentials that's how important cellular potentials are to communicate from cell to cell and neuronal Pathways and exocytosis and endocytosis and regulating the amount of fluid and ions that are inside the cell that's how important it is that more than 50 percent of the ATP you'll ever produce is used for those so that's a cool fact right not relevant to the MCAT but a cool fact number one okay this is mitochondria and it has an outer membrane and then it also has a inner membrane no another algebra membrane no then remember what are these Folds what are they called Chris stay you guys see how I color coded that isn't that so cool I'm actually colorblind so you're welcome oh where'd I get color blindness from by the way who'd I get it from no my mom why it's excellent no one else could have given it to me because I only have one X chromosome thanks Mom where'd she get it from my mom's not colorblind but where'd she get the gene from well it depends she could have got me from either Perry this is a woman right she got it from her dad okay so my grandfather's called one and I'm color blind okay Chris day what did Chris day do Chris Day increase the surface area for energy production have any of you guys ever heard of the coastline paradox so the coastline Paradox is basically like this idea that if you have a country right pretty up looking country right but if you measured the coastline using like 10 000 kilometer meter sticks then you get a very very short length but if you shorten it to like five thousand you'd be able to get in the grooves and then it get longer and then you shorten like a centimeter get even longer so like all coastlines are technically infinitely long right because you can just like fit more the smaller the smaller you go right so since there are these little grooves over here I want you guys to think that every single nook and cranny of those we're fitting more proteins for the production of energy right when you guys did orgo Labs what did you do to all of your reagents that were solid you crushed them up you crush them into a fine powder and then you add them to the flask why surface area there's more points of contact in order for the effective reaction to happen what's the effective reaction of the mitochondria cellular respiration to produce energy correct so since you have more Folds you have more ability to perform that reaction right what's the inside column The Matrix Mr Anderson right what's the outside called this part the intermembrane space the word I couldn't remember before for some reason even though it's just the space between the membranes the inter membrane space right what happens on the inside that we're so worried about the inside membrane it's the it's the house of the electron transport chain the ETC happens along the inner membrane so the Chris Day function to increase the efficacy and the velocity and the overall happening of the ETC the electron transport chain which is where we derive the majority of our energy what time is it by the way it's been an hour all right cool so probably just do like one chapter today and then we'll we'll take a look at chapter two and save the rest for next time you guys can feel free to leave whenever you'd like by the way okay so that increases the efficacy and the amount of like stuff that you have in order to undergo the electron transport chain right so the intermembering space in The Matrix allowed for a separation of several components of the electron transport chain and that will undoubtedly help us down the line right you guys know about like proton motive forces and like all the protein blah blah that's why we have the separation right okay there's one more really small fact that I always forget to mention about the mitochondria [Applause] mitochondria and the MCAT wants you to know this which is why I'm writing it down it has the ability to kick start Kickstart what not you Kickstart what all right say it apoptosis what is apoptosis not you program program and control cell death control and program cell death this isn't the cell exploding it's the cell taking Cyanide and drinking it right it's basically just like guys something's wrong here I'm gonna go kill myself before you die right that's basically what the cell is saying what's necrosis well necrosis didn't happen to a single cell too right so it's like it's just uncontrolled cell death right so necrosis and apoptosis right and if you guys like hop on the whole Anki wave when you're studying for the MCAT which I will teach you how to do eventually right whenever we get a bit more efficacious in our sort of lettering Styles I'll probably put it up on the screen you're going to see a bunch of cards about like necrosis versus apoptosis the curse of apoptosis is it super important not really to know the differences between the two of them that's more that's more of a medical school thing because the reason it's important to medicine is because when you look at a slide of cells under a microscope you want to be able to tell is that necrosis or is that apoptosis and that can tell you a little bit about the disease that's happening inside of the person that you've got the cell culture from does that make sense or the tissue sample right so that's kind of what you got to know about B kind of powder Jesus all right so one more thing remember how I said that your mitochondria are inherited from your mother right that is called extra nuclear inheritance that's where inheritance does not happen from the nucleus right extra nuclear inheritance because all of the other DNA and information comes from the nucleus right that's where it all starts from okay there's a couple other like small organelles they want you to know about so lysosomes right let's like break that down a little bit so we're gonna talk about like the smaller organelles because honestly the majority of the questions about organelles on the MCAT are gonna be about either the mitochondria or the nucleus but every now and again you might get like a little nugget of information about another organelle so let's talk about the first one being the lysosome why is that such an easy one to figure out why is that so easy figure out who has the word lysis in it or at least a derivative of it so that tells you that this organelle has a bunch of hydrolytic enzymes that can break down material some reason whenever I was studying I confused the lysosomes and vesicles a lot what are vesicles they're like little cardboard boxes basically that the cell is just like I'm going to put this in here and pass it off to someone and you're going to walk with it and drop it off somewhere else that's like what that's about this okay I thought lysosome what does lysis mean again lysis means two right right to break all right so let's talk quickly about the smooth and rough endoplasmic reticula and the way I wrote in my notes is probably the way it was in the textbook right let's talk about the rer is the rough endoplasmic reticulum and the ser smooth endoplasmic right what's the first fact about the rough ER what's so rough about it when you get shot and you go there no it's not like that what is it you said it ribosomes it is quote unquote studded Bros dripping with ribosomes so that means it can do what protein synthesis another one of my shorthands this double arrow means leads to this single arrow is an elaboration meaning that I'm explaining what was said before okay double arrow means lead to so stutter the Rob zones leads to protein synthesis right what's so special about proteins in the test huh you need the you need proteins to survive proteins are everywhere they do everything enzymes they're proteins Transporters they're proteins channels they're proteins pores and membranes they're made of they consist of like fats and proteins right proteins are everywhere in your muscles in you know like the space between neurons and everything proteins everywhere even inside your blood gold star to the person who can tell me the not you the protein in your blood that helps to carry other molecules around no that's oxygen but good guess albumin albumin okay I do this thing with my students over at downstate because I teach a lecture to the first year students as well every Friday so I'm with you guys on Tuesday and Thursday I'm a demo on Friday right so what I do and I forgot to bring them which sucks that's the other tragic thing to happen today I forgot my bag of Jolly Ranchers every single time someone gets a question right that I say is difficult I throw them at Jolly Rancher I just like wailing at them right so next time I owe you and who answered the other question use you right some someone answered another difficult question before not you and I owe you a Jolly Rancher all right so instead of the ribosomes and we talked about albumin right so albumin is most likely produced to the rough ER like when you talk about where these proteins are probably synthesized it's probably in the rough ER because that's where all the ribosomes are right yeah okay what about the Smoothie art two things about it that's the only thing you really got to know about the rough ER the Smoothie are two things remember what is that it lacks ribosomes which is why it looks smooth is that like under number one there's three things synthesis of lipids and detox drugs I don't know why they don't tell you this but the MCAT also wants you to know one thing the way we detox drugs is by making them more hydrophilic that's called first pass metabolism when like when you eat something right have you ever heard that whenever you eat something and goes to the liver first that's how first pass metabolism and when things get metabolized inside the liver like on first pass or on second pass or whatever what the liver is doing is it's modifying that molecule to make it more hydrophilic like that's how we detox things right so it's adding on molecules that make it hydrophilic and why are we doing that think critically think very very critically about why we're taking something that we want to leave the body big hint and making it more hydrophilic sorry dissolved in what in water and what does water make up a lot of the blood right and the blood turns into we are in and the urine gets excreted from the body so when we make something more hydrophilic we allow it to be dissolved in the blood the blood travels to the kidneys the kidneys filter it out put it in the bladder and you piss it out that's how we get rid of toxins right so I'm going to ask you a question there's a dead person in front of me right on this table there's a cadaver and I go into the cadaver and I slice off a really thin slice of muscle tissue and I go to the liver and I slice off a little bit of liver and I put the two things into a microscope I want you to tell me between the muscle sample and the liver sample which one of these is higher in each one so between this run ER and the smooth ER what's higher in each one because of exactly what we talked about right that the detoxification processes that happen within the liver happen within the smooth endoplasmic reticula so when you see an electron micrograph of a hepatocyte right and if those are weird words hepatocyte just means liver liver cell right and electron micrograph is a very very small microscope that shows you an image of a single cell usually right so when you take an electron micrograph of a hepatocyte you're able to see a lot of smooth ER but in the muscle where you need to produce proteins a lot of them you see a lot of rough ER does that make sense the second thing is the Smoothie art also helps to transport proteins from from where to where from the rough ER to the what's next the Golgi the Golgi also shorthand leads to explanation single arrows explanation double errors need two that's why I erased that Arrow over there okay so obviously we just talked about the nucleus thought about the mitochondria talk about lysosomes for some reason just like thrown in there let me talk about the rocking smoothie R what are we going to talk about next the Golgi right that that makes total sense and that's exactly where we go next right okay so do you see how the textbook is painting a picture for you right we have the nucleus which allows all of this to happen and we have the mitochondria which work together in order to give you the energy and the instructions on how to produce life after we transcribe things in the nucleus the MRNA from transcription right or transcription yes goes into the rough ER in order to produce proteins those proteins go into the smooth ER where they're transported over to the Golgi apparatus it's creating a timeline for you and they don't even say it and that's what I'm here for I'm going to tell you because if they don't tell you you'll never know and who told me no one had to figure it out my damn self actually professionality and he's the greatest Professor I've ever had in my entire life not at all I paid him a lot all right the Golgi apparatus let's just like read off of my notes here because I'm sure you guys know what it kind of was that weird Lobby thing with like a bunch of like it kind of looks like this it's like that and it like passes through each thing and all of those are like little membranes and when it passes through them everything gets put into like a little vesicle and those vesicles transport through the cell and that's how we get things from one place to another okay I'm gonna continue talking but Elena was kind enough to bring you guys snacks so you guys pass these around and I really don't care if you eat in my class um I don't even care if you fall asleep but pass these around if I don't want them right and enjoy you guys figure that out okay so I'm just gonna keep talking right so all right do you guys remember when you're like creating proteins you have a primary structure and a secondary structure and a tertiary structure and a quaternary structure right so the primary structure is one the chain of amino acids and if you don't know what amino acid is it's a basic building block of a protein right in a code it's coded for inside of your DNA and the amino acids come together and they bond and these things called amide bonds right and then they just chain together the primary structure is just a straight shape inside of those amino acids there are these groups that interact with one another through things called hydrogen bonds and the interaction of those hydrogen bonds creates the secondary structure where we fold into different components which we're going to talk about when we get to biochem right they fold into Alpha helices and beta pleated sheets you guys have heard this before right just give me an odd yes Alpha Gila season no never heard of alcohol season beta played the sheets and we'll talk about it we get to bio again basically it's the confirmation that proteins like to be in so they either twist around one another which is known as the alpha helix or they fold into these little sheets of diagonal even though acids called beta pleated sheets and all that does is it reduces the actual like you know repulsive forces between the molecules inside the protein does that make sense all right cool if you guys need me to move because you're writing something please let me know right Okay so then we have tertiary structure this is where the protein starts to like fold in on itself and it gets modified right what do you mean by modification well it might get phosphorylated or it might get hydroxylated or there might be a component put onto it or whatever whatever that modification happens in the golgiene protein mobbing I don't play video games here you're like downloading hacks off of the protein like you're making it more efficient at what it does right you're just just hacking it that's it right and then quaternary structure is very very special and it's only like talked about in a select number of proteins that you would need to know about and it's where multiple tertiary structures come together and they form one big protein complex anyone know an example of when that happens what protein in your body is a quaternary structure hemoglobin yeah hemoglobin right it's how many structures it's four right it's like four different terminals two of each type and I'm not gonna get into like the different things but like some hemoglobin is Alpha two beta two some hemoglobin is Alpha two gamma two and then some people have like a disorder where they're not able to make the proper type of like globin that's what it's called like a globin like an alpha globin or beta globin they can't make the proper one so their blood just doesn't work which is unfortunate right okay so you guys can see like you can't see my notes but you guys feel more right this is basically what I'm talking about here so we have the nucleus with the double membrane it's a up open nucleus right but the nucleus double membrane and all the DNA right here and it gets trans rounded it gets sent out one gets sent out we have mRNA coming out and then over here we have the raw endoplasmic reticulum which is continuous with the smooth endoplasmic reticulum which is continuous with the Golgi which is continuous with the outside of the cell right so when we produce neurotransmitters and hormones and albumin and proteins that need to either go outside the cell or into the membrane or into the cell this is where they go down does that make sense nucleus to rough to smooth what's so rough about that ribosomes nucleus to rough to smooth to Golden and then the Golgi is like that member to sting and when you pluck off those membranes they turn into vesicles and those vesicles carry the material that you just synthesize and either bring it back inside the cell or put it on the membrane or bring it out right I make this joke all the time to all my friends and they're just like wow dude you were just like so depressed okay so I'm gonna tell you guys this joke right so it three ways out of medical school what's number one what's the number one way out of medical school you graduate no no you don't drop out that's not number one that is not number one number one is you graduate you become a doctor what's number two you drop out right so either you graduate or you quit but there's a third one you could die right so there's three ways out of medical school you you drop out you quit and you die because they're not kicking you out because every year they can keep you is another seventy thousand dollars you're giving them they're not kicking you out right so there's only three ways for a protein to go into the cell onto the cell or out of the cell which seems straight forward right into the cell onto the cell out of the cell in three ways and for some reason right if you guys believe in like well if you guys believe in God or if you believe in the universe or if you believe in like crystals and energy and all that stuff for some reason everything in like the body can really easily be like turned into threes right but I think that's more so because of the human psychological tendency to think of things in threes than it is any sort of coincidence because honestly there's probably a thousand different ways to do things in the body but when we talk about enzymatic destruction of neurotransmitters and hormones and we talk about synapses in the nervous system there's all the three ways out of a synapse you get taken back up you get destroyed or you'll meet right and that's basically What's Happening Here you either get taken back up you get pushed out and then later destroyed or you leave and you just enter the membrane right break things down to really really simple terms this is something I tell all of my students right I'm talking at a level that a high schooler could come in and understand right right like I'm going very slow but raise your hand if I've taught you something that you didn't know before you came in this room that's how we do it you don't just start up here and just keep pushing you don't like train for absolutely no time at all and run a marathon you crawl and you whine and you complain and you trudge your feet and you slowly limp your way up until you can walk and you can hobble and you can run and you can jump and then you go we are crawling with both of our legs cut off right now and that's just how it's gonna be this first lecture I've taught the MCAT curriculum how many times maybe five or six to five or six different people right this is usually how long the first lecture takes it's the longest one and every single lecture after this gets faster I can teach two chapters of biochemistry in 45 minutes if you just stick along for cells to take two hours right because when we get to biochemistry what are we going to talk about his stones and protein folding and hydrophobic interactions and Golgi apparatus and protein synthesis and phosphate backbones all of which we just talked about right so when you encounter it a second time and a third time and a fourth time you'll be begging me to stop right because you're going to know it by that hopefully okay okay this is a cool little other um what's the organelle how many of you have had an infection before and I'm talking to the women when you guys get your ears infected after you get a piercing order the men if you have a ear piercing right but women more commonly get ear piercings and how many of you guys have had in fact a year yes yes yes my sister every piercing she gets infected completely just I don't know what the hell is wrong with it right not saline spray they give you like spray on your ear whenever it gets infected and sometimes they're like if it turns like a certain color put hydrogen peroxide on it right hydrogen peroxide okay so what's the next organelle we're going to talk about a peroxisome someone read the textbook a proxy cell it is filled with hydrogen peroxide in order to break down material in medical school yo we go wild over peroxide we go crazy because like all of your immune cells they use hydrogen peroxide in order to just like the out of bacteria also I have the filthiest mouth known to man right but it tends to help people remember things so excuse my language but hopefully you'll thank me for the future right so what is hydroperoxide it kind of looks like this right and what happened yeah right bigger gotcha all right it's like very difficult this is huge to me but it's probably very small to you guys okay it's all right bigger so this is hydrogen peroxide right and what happens it's filled with hydrogen peroxide H2O2 in order to break down material so this is similar to a lysosome but it doesn't use enzymes it uses hydrogen peroxide and we'll talk about how that happens when this hydrogen peroxide is primed to do something what happens is you get a dissociative reaction this is called a heterolytic bond dissociation right because it goes two ways heterolynic right and what you get is two of these hydroxide radicals and those the most information you need to know about peroxide those can just rip things apart because that radical that little electron it's really really hungry for a partner so what it does it just starts nabbing electrons off of a bunch of other things and then those radicals that form pair together and then it neutralizes the toxic capacity of whatever compound you're breaking down does that make sense so in peroxisomes we use hydro peroxide to produce radicals which are known as something that you're going to read about in a lot of Articles when you start answering questions about the young guy they're known as reactive oxygen species Ros reactive oxygen species if you guys know Professor Greer Professor Alexander Grier at Brooklyn College most of his uh research is about reactive oxygen species very interesting stuff does that make sense we're almost done with organelles we are going to talk about the cytoskeleton in transit because what's going to happen is like you're gonna get asked so many questions about it later down the line you're just going to learn from that because me lecturing it to you and I've noticed that like me lecturing it to you guys and even trying to learn it for myself just reading it and writing it it doesn't work because it's just the same thing over and over again so I'd rather you get down the line get to the questions and understand them but definitely read the textbook and like try to understand what's written there okay well the one thing we're going to talk about is the fact that microfilaments and this is the biggest thing microfilaments which are a component of a component of the cytoskeleton these are made of actin actin that's the protein that makes them up right okay and this plays a role in cytokinesis cytokinesis being the separation of the cells when we do mitosis or meiosis right foreign is microtubules these are easy to remember because they're made of tubulin tubules made of tubular right microtubules made of tubulin and microfilaments made of actin right okay one thing about microtubules is that they're involved in the synthesis of cilia and flagella where can we find cilia in the body and where can we find flagella in the body cilia where yeah sperm cells right sperm cells have flagella that's how they move around and actually there's a diagram inside of the reproduction chapter which you guys should open up I'm talking about the Catholic Books by the way right those are the books I use those are the books everyone should use in my opinion if you look at the reproduction chapter of the Kaplan books there's a diagram of the actual like motor function of the sperm and there's this very cool like motor looking thing inside like it literally looks like an engine it's super cool but the end of that is flagella which allows them to move around cilia where restore track right and they help to kick up dust and other pathogens they're these tiny tiny little proteins that kick things up and if you either expire them out or you sneeze it out or you cough it out or whatever or something that's really disgusting and that we learned in medical school is that the Cilia moved this stuff up and then you just swallow it and then it gets destroyed by your stomach acid so you're like swallowing dust and dirt and that all that stuff all the time okay so that's a little bit about cytoskeleton right um centrioles right those are involved in mitotic division so those are like these are all the Lesser sort of known and talk about working out centrioles are involved in mitotic division right and a microtubules kind of connect to this uh centrioles and then it pulls things apart right doesn't heard of sensorials um and then there's just like other things that you don't really know need to know about all too much uh intermediate filaments you're just going to hear the names of it all the time those like keratin Diamond sing all that stuff and then we get into a sort of part of the chapter that I didn't think was super relevant um it's tissue formation right tissue formation so what are tissues so you're talking about cells right and we just explained like a whole ton of a lot of how cells work what are tissues they're just organized sheets and cells right tissues organized sheets of cells right those four tissue types there's epithelial tissues connective tissues muscle tissue and neurons neurons nervous or nervous tissue right more specifically another thing they don't tell you these are somewhat organized in restorative or regenerative capacity exact muscle tissues in what I've learned have a little bit more capacity to get it then connected so epithelial tissues are pretty good at regenerating that muscle connective and neurons so like their neurons are quite bad every generally connected tissue is quite slow muscles regenerate slowly but faster than others and hypothelial tissues regenerate quite fast okay what what are applicable tissues like you hear this word thrown around the epithelia right laughs in the textbook they say it covers the body and lines of organs and does this and forms the parenthema and voila they're functional they're the functional tissues of the body they perform function right so it says epithelial cells usually make up make up the parangular the functional unit of an organ right so when we talk about like liver epithelia or lung epithelia ordered ovary epithelium right it's the stuff that does the work right does that make sense cool have you guys heard of like the layer thing where it's like simple stratified pseudostratified blah blah blah yes no any nose kind of right so like stratified or sorry simple as just like one layer so it's just like this as one layer stratified is like multiple layers and it's pseudostratified is like the little cuck who's sitting there like this so it looks like it's multiple layers but it's really not and they like overlap over one another that's pseudo-stratified so when they say stratified epithelium or simple epithelium all they're saying is like how are the cells arranged right so simple is one layer stratified is more than one layer pseudostratified looks like it's more than one layer but it's actually it actually just wants you to do bad on your exam and you got shapes cuboid all columnar sweetness blah blah blah right the chapter goes into a little explanation of like how to classify prokaryotes I don't find this section of the chapter very important I don't find it super important to discern between like Archaea and bacteria the only thing there is that like they both exist under like back like under prokaryotes right and that archaea live in like really really harsh environments that's pretty much the only thing you know right well the one thing they do is they talk about these shapes of bacteria which come up all the goddamn time right so we have cockeye bacilli spirulinai who can make a wild guess what this one is spirals they they go like this they're the fun ones anyone ever read Uzumaki by juji Ito you should it's a fantastic book well it's a manga but it's about spirals what are they they're dots right they're little circles Spears because apparently the world is 3D what about this lie they're raws you guys know that like you guys know that Meme of like a metal rod like dropping on the floor and it makes a loud noise or am I just like stupid all right never mind all right arrows and anaerobes all right what does obligate mean if something's obligatory onto you like I'm Muslim and my prayers they're obligatory which means I must do that right I have to right so if something is obligate to you you have to do it right so when we're classifying living things and we say that something is an obligate a robe what do we mean it needs oxygen to survive is that us I sure hope so because then it's not get the hell out of my room what's next obligate anaerose obligate anrose they cannot survive in the presence of oxygen they would die why would they die we talked about it earlier who remembers what we talked about what does Ros stand for reactive oxygen species something about these organisms when they come near oxygen they turn it into reactive oxygen species and they just die right what's next facultative aneurysms right let's facultative anaerob mean they switch I can't spell they switch to anaerobic processes when beneficial so like our cells are technically facultative anaerobic because like if we don't have a lot of oxygen around they can switch to anaerobic processes right we can like switch to only using glycolysis and kind of turning off Pacific Gas cycle but we still need right we as as humans as a system we need oxygen and it's not that our cells aren't using the oxygen they're just doing a little more of the anaerobic respiration right so like a little bit of this but there are sort of organisms that can switch to anaerobic and switch back and switch and switch back right there's one more this is the easiest one Aero tolerance aneurysms Arrow tolerant anorems I know it's quite small but is this Aero tolerant anorems right what's an aero tolerant anaerobic it's anaero right so what's it doing it's not using but it tolerates oxygen so if my sister's annoying me right it's not like I'm gonna kill her if she's in my room or I would die if she was in my room I would tolerate her being in my room right I don't want her there and I have no use for her but I tolerate her being there so it is an aero tolerant anaerobe it's not going to use the oxygen but it's not gonna die either right all right one important thing about prokaryotes something we didn't put up on the board before I don't know why it's not like listed in the uh in the Lexicon textbook the latest we have an extra napkins by the way yeah I'm just gonna use one to erase the board so what did we talk about before like the differences between prokaryotic and eukaryotic cells what did we not touch on some prokaryotes have a what a cell wall what's a cell wall what's a cell wall it's a wall that it's it's a wall that surrounds the cell which you believe in right it's a prokaryotic cell wall two types gram positive gram negative definitely need to know this video like a hundred percent of these modes forget that where I'm positive has something known as a thick peptidoglycan layer peptidoglycan is just this special like modified protein that exists on the cell walls of prokaryotes right that's peptidoglycan and in a positive in a cell wall of a grant positive bacteria it's a very thick peptidoglycan layer which means gram negative would have a very thin pept you don't like them there a very thin captured like that right and one more thing that doesn't really come up with the MCAT but it might since they mentioned it you might read it somewhere these contain something that grab negative bacteria they contain something known as lipo poly saccharide lipopolysaccharide or LPS right what is lipopolysaccharide what's up yeah it's an endotoxin have you taken Immunology or microbiology before yeah there you go so basically lipopolysaccharide was evolved by bacteria to make them more pathogenic what does pathogenic mean causes disease right so pathogenicity is the ability for bacteria to produce disease correct so this lipopolysaccharide makes them a lot more dangerous to our bodies they activate the immune response and that's why like E coli is so bad because it's gram-negative the lipopolysaccharger it causes widespread massive disease inside your body does that make sense oh what color is something that is Grand Honda purple and then grab like it is big cool how are you gonna remember that what's up yeah right you see it will add you memorize it you figure it out right oh here's that little diagram I guess it's in here we can talk about flagella yes see that diagram over there like if you look in chapter one looking that is the tail of the sperm it's so cool I'm gonna show the camera so that is your little like motor that exists inside of this burn cell and it allows for motion right so that's kind of what's going on and they talk about flagella a little bit you would never believe that the flagella is composed of a protein called flagellin right scientists are so creative right cool cool all right so the reason we're talking about hotel is because a lot of prokaryotes have flagella right cool that's how they get around and things like that right one more thing they don't have mitochondria right we talked about that before but one more thing that comes up every now and again on the MCAT is the size of the prokaryotic ribosome you guys in a couple weeks are gonna be my roommate his name's Steve and Steve is a great guy because he taught me a little trick about the ribosomes you go 30 40. 50 60 70 80. and you go s s s s s and this is pro and this is Uke and you add these together and you know that the prokaryotic ribosome has a 30s and a 50s subunit that somehow becomes a 70s ribosome and you know that the eukaryotes have a 40s and a 6cs they become an ads ribosome what do those mean those are called spedberg units right svenberg units and it's a unit of sedimentation time so they took these little like uh subunits in the whole ribosome and they see how quickly they settle down to the bottom some sort of mixture right and then they took the guy who did that experiment just tacked his name onto the unit right so it's called spedberg units right sedimentation time for some reason 30 and 50 become 70 and then 40 and 60 becomes 80 but that's what it is so the prokaryotic ribosome is a 30s and a 50s subunit the eukaryotic the 40s and the 60s subunit you will get a question on the MCAT about this it will happen a hundred percent you gotta know that and the sad part is I didn't meet Steve before I took the MCAT I had no way memorizing that before and it was the fact I didn't know I probably got that question wrong okay so we're gonna talk about growth prokaryotic cells binary fission right binary basically the cell decides it wants to become two cells it replicates its DNA and just dissociates that's really it right but there needs to be a way for bacteria to kind of diversify their genome or else they want to die right or else they kind of would have just not made it right so we have a lot of ways of genetically recombining our together DNA inside of bacteria and those four things are free things I guess our transformation conjugation and transduction okay it's number one is transformation number two is conjugation and what was number three transduction right so transformation what happens so basically a bacteria dies right and when it dies bacteria dies which leads to release of genetic material which leads to reuptake by other bacteria and in that dead bacteria had genetic information that that bacteria didn't have it now has it right so let's say that like there was one gene one extra Gene inside of a bacteria that died and it gets released out of the environment and this one bacteria that really needed that Gene takes it now it has it done debt uptake done genetic diversity right it's like any of you guys ever watched Naruto right we're like uchihad Clan number dies just take his eye and put it in yours and now you're going to charge it up right so that bacteria just got the showering though that's what happened right so dead bacteria take its DNA easy so I go to a dead guy that steal his wallet now I got all his money very unethical but now I got his money right what about conjugation it's bacteria sex right it's bacteria sex what's a plasmid it's a little circle of DNA so this is plasma transmit so plasmid is a circle of non -nucleoid DNA why did I say nucleoid because like bacteria don't have nuclei but they have DNA inside of this region called the nucleoid region am I right bacteria guy yeah so that's not nuclear DNA it's aside from that so this is a little circle of DNA that the bacteria just has somewhere lying around correct now if the bacteria is f plus it can initiate conjugation what does f plus mean so basically if the bacteria has a g that allows it to have the ability to create a plasmid or sorry to create a conjugation Bridge it will so let me explain what I mean by that okay can I erase that on top so let's say that we have let's say that we have two bacteria what's the shape of those bacteria by the way they're bacilli right this one's f plus because it has a plasmid that allows it to form a conjugation Bridge right and this one is f minus I think that is fertility right so that was fertile and that one's not right so what happens is that this is the nuclear region and let's say that this is the f plus plasmid that's the plasma that allows you to make the conjugation Bridge right it's gonna copy that DNA into another plasmid and now there's two of them do you need two of them no right so that plasmid codes for proteins that allow it to make a bridge and a bridge is called a pilus right so they're going to grow out of here and it's going to grow a little more and it's going to grow a little more and it's going to grow a little more until it attaches over here right and that is called a sex Pilots that's why it's bacteria sex it's called a sex piles right and what happens is that plasmid slips through the sex Pilots and into this F minus bacteria and that leads to the formation of two f plus bacteria what's the point what's the point if that's the only thing we're like to referring because eventually at some point it may happen that a bacteria dies right and through the process of transduction you pick up a gene you pick up a plasmid that you want to give to someone else and now that you're f plus you can replicate that plasmid throw a conjugation Bridge or yeah conjugation break or throw a conjugation or a sex pilot and transfer both those genes onto another bacteria and this is how bacteria confer resistance you guys ever heard of MRSA and Bursa methicillin resistant staphylococcus aureus or Vancomycin resistance staphylococcus aureus right they confer resistance through DNA changes that have occurred evolutionarily and they give it to other bacteria in their population and now you have a problem that you can't treat that staph infection with Vancomycin or methicillin right that's how that happens transduction is the one that Everyone likes why why is transduction the cool one you're using something called A bacteriophage with a phage a phage it's a virus right a bacterial victim a a virus for bacteria bacteriophage to inject DNA into a specimen they look like this sorry orgo people for scaring you with the hexagon you're like that and it got all this DNA in here and they come up to a bacteria and they go that's it and then that DNA what does it do it integrates into what into the native bacterial DNA the DNA opens accepts the new DNA and now what can what can it do it can replicate that Viral DNA for whatever it wants either the synthesis of new viruses or the con like the the use for sort of what's it called um resistance or blah blah whatever it is and it got that from a virus that makes sense virus is alive or not moving packets of genetic information all right very good uh they talk a little bit of prokaryotic growth all you want to know is that the graph looks like this what happened here they exhausted their resources what happened here they're adjusting to the new environment what happened here they it they they are they are replicating out the back door until they reach a phase where the amount of resources they have is equal to their potential meaning that they're dying at the same rate that they're reproducing that's called the exponential phase the lag phase and the death phase oh sorry no that's a lag phase that's like I think that's called the plateau phase stationary things lag exponential stationary death makes sense anyone want to take a break are you guys all right if you're all right I'm gonna keep going yeah all right okay we're gonna talk about viruses and sub viral particles so like I said before viruses are not alive they're not made of cells they don't really have organelles right so they have genetic material a protein coat and sometimes lipids right but basically what happens is that most viruses just have a little shell either like this or like this then there's a genetic material in there and that genetic material is held inside of what what is this thing called capsid and it's made of proteins and since it's made of proteins it can denature and denaturation is breakdown of protein material so it's sensitive to pH sensitive to temperature blah blah blah so when you get a fever when you have a viral infection what's your body doing trying to kill the virus right should I kill whatever's effect right and honestly the rest of the information about viruses you kind of talked about it so here it says viruses can't represented cells they're obligated intracellular right we talk about bacteriophages thought about enviral genomes so basically it can be single strand or double stranded RNA or DNA I don't know why they say that because that's literally all it can ever be either single-stranded DNA or circular stranded RNA or double stranded DNA or double stranded RNA right okay the one thing that we haven't talked about yet right retroviruses what's the most famous example of a retrovirus most famous example of a retrovirus HIV what does it stand for human Amino deficiency virus because it takes your immune system and just goes done and now you dive in common cold sucks right okay so retroviruses basically have this enzyme called reverse transcriptase where they take RNA and turn it into DNA and like bacteria right where the virus injects this genetic material into the bacteria and it integrates into your DNA if the virus makes DNA and it enters your body it can enter into your DNA and now you're doing the work for the virus and sometimes that virus can code for proteins which destroy your immune system you live a very very long and painful arduous life and pass away from a common infection and that's what happens when people get HIV and AIDS except we have drugs called antiretrovirals now which are very good against HIV because they inhibit reverse transcriptase right reverse transcriptase Inhibitors are antiretrovirus right okay medic versus lysogenic Cycles we've talked about that already right so basically two things can happen number one that DNA integrates into or DNA RNA whatever it is it gets transcribed and integrates into your body right now either the DNA can integrate and it'll just keep copying copying copying until it's copied into thousands of cells right a millions of cells and it just lays dormant but that Viral DNA is just there and sometimes it'll code for proteins that are pathogenic and ball a lot you get a low-level infection but things can enter that's called the lysogenic cycle right where it integrates and just goes and goes and goes and goes right viruses and lysogenic cycle can enter the lytic cycle and I don't exactly know what the signal is for that because I'm an immunologist right but we have a great eighty dollars over a downstate in Alaska right so if they can enter the license exit the lysogenic cycle and enter the Linux cycle where they form all the proteins that are required for viral synthesis and produce hundreds of thousands of viruses that blow yourself to pieces and they distribute all over your body and they inject their DNA in other cells and repeat the process over again see how that could really hijack your body right because let's say that one viral particle did that and then it replicated to a hundred thousand cells and those hundred thousand cells each made 10 000 viruses and now those what 1 million 10 million viral particles go and infect one million or 10 million cells then those 1 million 10 million cells become a trillion cells all infected and all of them blow up with 10 000 viral particles you've got a problem now that's why they're so good at survival cool what's called what is super infection super infection is when you're affected by more than one virus at a time it could be on the cell or on an organism last fact out of this chapter and it's one of my favorites if you guys don't mind we're almost done like we're gonna be done like 10 15 minutes but I need to explain Alpha helices and beta pleated sheets before we go on to this next point is that okay yeah all right I promise it's worth your time and thank you guys so much it's really hot in here and you guys have been super patient and very receptive I really appreciate it because listen if I'm doing this it means I have the time to do it well whether or not I have the time this is more of a distraction to me from my actual work than anything else right this is like an escapism and I also enjoy it I love teaching but the fact that you guys are here when you clearly have better things to do I really appreciate it and I hope that you guys stick around and tell your friends if you guys got something out of this tell all your friends I would love to see a packer room right okay so we previously talked about amino acids right water amino acids the building blocks of proteins biochem and orgo people I am so sorry to bring all this back and you don't understand what's on the board it's fine this is an amino acid and that R Group means that it can be anything right it can be like a methyl group or well not anything but it can be like any multitude of a bunch of different things right that's what amino acid right and in your DNA there are these codons and those codons get transcribed into mRNA and those RNA codons get read by ribosomes and those ribosomes signal for the addition of an amino acid into a chain and that's how protein synthesis occurs in very basic terms we're gonna need to know it in a lot deeper terms soon it is so hot up here okay so that's amino acid and it's going to add to another amino acid in what type of a reaction this is called a dehydration synthesis where H2O gets kicked out right and it's going to look something like this I'm going to put R Prime right here so you know which one went where okay so right these two hydrogens from here and this oxygen right here got nabbed away before H2O and now we have a connection between this carbonyl oxygen and this nitrogen who knows the name of this functional group this functional group right here it's called amide right or in a mid an ammeter and a mid professionality was Notorious for saying Amid and he swears that's the correct way to say it right that is a ridiculously stable body and we're going to talk so much so much about this bond between this carbon and this nitrogen we get to orgo because if that Bond didn't exist we wouldn't exist and if that Bond didn't exist exactly the way it exists we would never exist our entire body and all of its processes and all of our DNA and all of our proteins are contingent upon the existence of that Bond exactly how it is it's a beautiful thing and we're going to talk for 15-20 minutes about it all right so the amid bond is very strong so now this is something we call a dipeptide diet meaning two and peptide meaning protein right so peptide is a protein and a dipeptide is a two amino acid protein this isn't really a protein and it's just two amino acids right but this is not called a monopeptide this is called amino acid the amino acid is a tripeptide and then turns into a polypeptide many amino acids right but when these get linked together right and the way you know your dreams properly is that when they get linked together can you guys imagine that another amino acid comes to this terminal right here and there's another NH3 oops there's another NH3 group our double Prime and those are going to add together can you imagine that right the same way these did in your notes you can look and see how they added and that's going to do the same thing so the way you know you do this right professional let's get always said is if your carbonyl groups are facing in opposite directions you did it right or triple prime R double Prime R Prime R down up down up right if you go to opposite directions you do it right h h and that's it you guys see how there's a lot of oxygens a lot of nitrogens a lot of hydrogens who remembers the rule about hydrogen bonding chem is Fawn f-o-n right so Hydro bonding what is hydrogen bonding it's not really a bond it's a very special strong interaction between specific hydrogens and acceptor electrons so in hydrogen bonds we have donors and acceptors right and it's a special type of intermolecular force right enter meaning between two and molecular meaning molecules so it's a special force between two molecules and we have donors and acceptors so whenever there is a hydrogen connected to an oxygen or a hydrogen connected to a fluorine or a hydrogen connected to a nitrogen that's a donut and it's all going to make sense in one second if it doesn't make sense now and what's the acceptor it would be the lone pairs on an oxygen or the lone pairs on a nitrogen oops or a lone pair on a fluorine so these electrons are the acceptance voting about donor and acceptor well if we have water which looks like this and then we have another water molecule like this they're going to orient themselves in a way do you guys see like there's a line going through the hydrogen that line is going to link up with this electron pair and that's going to be a hydrogen bond like that and that's why water configures itself so nicely into ice it has like that crystalline structure because it lines itself up into hydrogen bonds does that make sense so that's an ace Bond not an edge bomb Oppenheimer but an h-bond right okay so proteins are capable to your photo everyone take a photo if you want everyone if you have to look at that every really important so can I erase did everyone take this down do you need a moment all right so those interactions they're really strong and since they're really strong they give us back a ton of energy when they form I'm not going to talk about what we mean by giving back energy that's thermodynamics we're going to talk about in general chemistry and it's honestly probably the most important chapter of the entire book thermodynamics is very difficult to understand we're gonna have a whole electronic by itself but do you guys see here NH and then over here we have a bunch of oxygens with lone pairs around them right so what's going to happen is that the n h and the oxygens are going to link up in a way that lines up those electrons to that donor and that's going to be an h-bond does that make sense so the protein is gonna get super long like if I could I would write that in like this big of a font and it would probably spam the entire board over here and more and keep going to a South Korea right so what's going to happen is that that very long protein is going to twist and contort in ways that match up the donors to the acceptors and not just the oxygen acceptors the nitrogen acceptors as well because look on your sheet the acceptors are the lone pairs of oxygens nitrogen and florians floorings don't normally happen inside of our body so oxygen is a nitrogens mostly right and when they configure like that there's two ways they normally configure number one is in an alpha helix and number two is in a beta pleaded sheet and Alpha Helix and a beta pleated sheath what stage of protein folding did I say this was we have primary which is the line going to South Korea right this is secondary when the protein contorts and contracts itself to line up the hydrogen bond donors to the acceptors that secondary protein folding so this if you want to write notes secondary structure of peptides begin using the scientific terms familiarize yourself with that with them everyone following yeah give me a head nod good and Alpha Helix is what it sounds like it's what it sounds like it's a helix it twists in on itself right and on the inside what do you think we need polar or nonpolar things on the inside away from The Polar environment the non-polar things come right so you're a rule of thumb for the body polar things outside non-polar things inside because the body is mainly just like water circulating around and water is super polar so as to not disrupt water or not disrupt whatever molecule we're making all the non-polars they kind of cave in on the inside right so on the inside the Helix is usually nonpolar stock the polar stuff layers on the outside and it twists around and it forms a little column right cool and we're going to talk more about this when we get to biochem right because there's one amino acid that doesn't follow the rule when it comes to Alpha helices what is it it like kind of up the alpha Helix a little bit Proline Proline is the amino acid that up the alpha Helix what happens is your Helix Helix Helix Helix and a ProLine comes around and you go Helix Helix Helix and this is called a kink don't take shame Crowley's just doing its job see I have so many one-liners man and this guy's always laughing all right so we got Alvin Ulysses what about beta pleated sheets do you guys know issei Miyaki rest in peace he's a really nice designer right from Japan and he has this he has this um collection called omprice which means depleted men right so what happens is the men's collection of a bunch of clothes that have pleats in them folds they're little folds like this and all of the pants and shirts they look like this from the top down so they have these little folds and like when you get dress pants tailored someday they're like oh you want cleats that's what they do is they take your pants they fold them over themselves and Stitch it like that those are pleats so when these beta pleated sheets are made I don't know why the they're called beta because the first thing was called Alpha why didn't you just call it Ulysses and sheets and the Hero season pleated sheets why the apple and the beta his Alpha Beta I mean 20 different things can go to 20 different continents right but anyways beta pleated sheets what happens is that the protein lines up like this [Music] and then another part of the protein down the chain somewhere closer to South Korea lines up like this and the hydrogen body interactions happen between those two parts of the sheet right we're going to talk about the scariest thing in medicine these kill you ever heard of mad cow disease mad cow disease is something can I erase this something known as a prion disease prions are aberrant pathogenic proteins what does a barren mean unregulated They Don't Really follow rules and these proteins normally are one what do you what do you think they are why'd I give you this 20 minute rundown they're usually beta sheets and beta pleated sheets and what happens is that these sheets of proteins come into your body because you ate the brain of a raw cow like the raw brain of a dead cow right and it has these proteins inside of it and what it does is it collides with one of your well-formed proteins and unfolds the whole thing because this is such a strong like attractive force that your protein just goes ahead and joins the party and then that four folded pleat goes on and hits another protein goes five then it becomes six and seven and eight and after a while you have about this stack of a hundred different proteins just knocking into everything you have and unfolding it and then you die because your proteins no longer work that's prion disease so they put it at the end of the virus section of this chapter because they're not really viruses because they're not contained in anything but they're just pathogenic proteins the one of the notes I wrote they're infectious wrongly folded proteins or infectious misshapen proteins make sense cool go home no I'm kidding all right guys thank you so much for coming just a couple words before I leave um number one please tell your friends to come because I do not want people to miss out on the information I'm giving but of course I recorded the whole thing I really do hope this is still recording oh thank God