all right it is time for the long-awaited unit 6 gene expression and regulation i have no idea if it's actually long-awaited but dude this thing is massive so so it probably is some part of it long awaited okay all right hello everybody i'm kara and today we're just going to be going through all this good stuff let's do it so the first thing we got to talk about when we talk about gene expression and regulation is first off the molecules that store genetic information and do all the cool stuff in a gene expression all right so the two molecules we're going to be talking about are part of a family of molecules called nucleic okay that that is not how you spell nucleic acid nucleic acids and basically these just have a phosphate group right you have your pentose sugar right five carbon sugar and you got your nitrogenous base so that's literally all you gotta remember right you got your phosphate you got your ribose you got your nitrogenous base and then basically they connect to each other like this right and you got another one over here very cool and basically each one of these is called a nucleotide right but then when you put them together you get nucleic acid all right and then this thing over here right is made up of a phosphate and a sugar and it's kind of like the back one right they're all connected to each other so it's called the sugar phosphate backbone okay that's another important thing to remember okay so now the two main nucleic acids we're going to be talking about are dna and rna and you guys know what they stand for right right come on it's pretty it's pretty cool trivia deoxyribonucleic acid wow and ribonucleic acid and as you might expect the main difference between them is deoxy this one visiting an oxy this boy has an oxy very cool so essentially you know how like the pentose sugar right and basically an rna there's an oh here and then in deoxyribonucleic acid there is an h there right so obviously you just get rid of this oxygen when you make a di d what deoxyribonucleic acid so why don't we draw up a molecule of dna right you gotta know that like dna looks kind of like this right like you've seen it in sci-fi forensic movies whatever it's basically a double helix right you got two strands they're twisting around each other double helix and then you got like random base pairs pairing with each other very cool but how did that look at the atomic level so if we draw it out again using our phosphate epicness we get something like this dang the stress of my drawing skills holy that took me so long to drop by doing it but you can see right the sugar phosphate backbone on this side there's a sugar phosphate backbone on the other side and essentially these nitrogenous bases are connected to each other with something called hydrogen bonds all right so i'm going to just get rid of rna because i need the whole screen goddang and basically you know when two bases like connect to each other it's called base pairing so another important thing you got to know for dna is base pairing all right so you guys probably know that dna has an alphabet right that's how dna stores information right it basically has a bunch of these nitrogenous bases which are a t c or g and based on the sequence of atc and g you encode information basically the way i like to remember it is i just like to think of it as like app cg at computer graphics i don't know i don't know it's just something stupid okay i just need to remember that atcg okay then the adjacent ones are paired to each other so a t pair sorry i can think of anything cooler but you know it does its job okay a t c and g so these guys can pair and a c cannot pair with an a c cannot pair with a t a g can occur if it's t so on and so forth these are the only ways they compare so what's cool about that right if you know one sequence right you know a t c g right then we could figure out what the other sequence right if we know this side we could figure out the other side so the other side would have to be what pairs with eight t here the thing one pair of teeth eight pairs of d one favorite c g p z and what pair of the g that's right see here's the g very nice and array we got the other string now a really annoying thing that bio teachers do just kidding this is the bio thing in general but there are directionality to these strands like you can see that like the pentagons are facing upwards here but they're facing downwards here holy moly now that is great so basically they're parallel but they're in opposite direction so this is called anti-parallel and basically the side with the phosphate group is just called the five prime end you could talk about the carbons right like the one prime two prime three prime four prime five prime carbon somewhere in there but basically just remember that the phosphate side of the five front and the other side the opposite side with nothing on it is three prong so thankfully one side goes from five five and three prime but the other side goes from five primes to three runs the other way so now let's go back to our example right we have a t c g and t a g c so this one is five prime to three prime right but don't get messed up on this on the test right completely they go in different directions so you have to make sure that you put three prime to five primes all right very cool now one last thing we got to talk about for dna right is the structure of the nitrogenous bases right so what the heck does the nitrogenous base even mean basically we have a t c g right so basically each of the letters actually stands for a molecule right so a stands for adenine and basically adenine looks like a pentagon slab onto a hexagon okay it literally looks like that and then there's thymine right and that just looks like a hexagon with stuff branching off of it randomly i don't remember the exact structure but yeah it's basically a ring a six membered ring and then there is guanine for g right and that's another of those random pentagon slapped on hexagons i don't know why pentagons like slapping hexagons so much but they do and then cytosine is just another hexagon so can we see a pattern here holy moly two of them are hexagons and two of them are non-hexagons and basically we saw that a pair of teeth so a non-hexagon has to pair with a hexagon and a non-hexagon has a pair with a hexagon opposite the track very makes sense a lot much lee very cool i'm so bad at english but then you can also see that there is a similarity between these two and there is also a similarity between these two right so the bigger dudes are called purines and the way you remember that is pure as gold right so pure for purine and then a for adenine and g for guanine all right and then the other ones are called pyrimidines now this part's not as important but honestly just the more like connections you make about the nitrogenous faces the better you're going to be able to remember how pairing works and all that good stuff okay so now it's all cooling all right we got like all these random letters we got like dna doing anti-parallel nonsense what the heck is the point well basically dna are in your chromosomes and you guys know that your chromosomes get passed from parent to sun so essentially those letters encode exactly what it passed on if we look at like a tiny part of the chromosome it's literally just really coiled up dna and guess how many base pairs a human cell have that's right six billion it's crazy holy moly that's a lot of stuff and that's in 46 chromosomes so there's like a ton of dna in one chromosome alright so that's all the important stuff about dna why don't we talk about rna so while dna is utility in a double helix right rna is usually single stranded okay now there's obviously exceptions to every rule but generally speaking you're going to find it single stranded and then the other difference is that the nitrogenous bases are different right like in dna you have atcg right but in rna you have aucg so instead of at computer graphics you are gold computer graphics get it hey you hop get it i know i'm so good at this kind of stuff bro so basically instead of thymine you have something called uracil and that is also a hexagon boy uh pyrimidine very cool and instead of encoding genetic information it does technically code genetic information and viruses and stuff but generally speaking in humans rna is used for helping out with like gene expression and that kind of stuff so i'll give you a quick overview mrna right messenger rna that's what is transcribed from your genetic code and is sent out into the cytoplasm to make protein then there is trna transfer rna right that transfers amino acids to the ribosome so they can actually put it in your proteins right and then there is rna ribosomal rna guess what it does it's in your ribosome and it helps your ribosomes make stuff very cool all right so now just a really quick distinction right well we have these beautiful x chromosomes and we have like 46 of them prokaryotes only have like one circular chromosome okay so don't get messed up by that remember that in prokaryotes you only have one circular chromosome and that changes how dna replication is done it only has to go on one chromosome all right so now we've got to talk about dna replication holy moly so the first rule the one number one the only rule you have to remember about dna replication is that it only works on the three prime end okay you can only add to the three prime m okay you can't like add on the five prime man that is illegal can only add on the three prime end and this is the only thing you remember you can login your way out of dna replication so easily it's not even funny okay so just remember that all right so now first off we have like this dna right it got all the letters right here right we got our base pairs we got a t c g i don't know a t c g because why not and t a g c so on and so forth so now how the heck could we replicate this can you guys like just take it take a wild guess huh how how how can we replicate it well i i mean i have a cool idea right what happens if we like unzip this boya and what happens if we added a new strand over here and it was like t h g and we just kept adding it on this new unzipped thing and then great we got a new molecule of dna that's crazy so basically what happens right is basically you have your dna right and some enzyme called the helicase comes and splits it up right so now you have a fork very cool so helicase does that and now you have these dangling like nitrogenous bases on either side and then if your body wants to replicate it all you got to do is base pair stuff to this right you just pair it up right if this with the a pair of t to it if this was a t you pair an a to it and so on and so forth and then once you're done it'll kind of look like two completely separated fans right the whole thing will get unzipped right and then you have two separate strands one here and one there and this part came from the old one this one came from the old one but these two came from the newly created base pairs very cool so let's go back to the fork because we're not done yet so let us say that this is the five prime end and this is a three prime end right and this is the three prime end and this is the five now basically the way this works is that first off we add a primer right we have an rna primer right and basically what this lets us do is like you can't just randomly start base pairing without anything to start from so essentially this enzyme called rna primase kind of creative but it basically just puts an rna primer on the first tube and then now dna polymerase could come along and start adding to this side right because there's a three primeknit five prime three prime right it goes opposite direction at the bottom string so now dna polymerase could have a field day adding random things until we get all the way down to the end of the screen and as you can tell this strand could just keep going right because like it could just keep going the fork that's going to keep separating very cool stuff so because this one could just keep going with the like fork right as the fork gets bigger this one just keeps going then this is called the uh leading string however the other side is a bit more complicated so why don't we just make this a bit bigger so it's easier to see five prime three prime all right so that means our new one we have like a bunch of bases right here right that means like right now if the fork is right here we have to add our primer right here and this is going to be the five prime end and the three prime end which means we can only add this way right so that means if the fork extends more this way right like if more of this part opens up right we're left with all these guys then we can't add onto this primer we have to add a new primer over here right and then start going so basically you're forced to make a bunch of these different fragments as the fork gets bigger right because as the fork gets bigger you can't continue the previous one you have to put it somewhere else so these fragments right here are called okazaki fragments okay and basically the top strand is now called the lagging strand right because you literally have to lag it's not right at the fork right you have to wait until a new fragment is created before it can start like making that part the leading one on the other hand could just keep going with the fork so it's leading with the fork but this one it lagged a little behind the fork and then like obviously you don't want to have a bunch of random fragments like cuts in your dna backbone so basically another enzyme called dna ligase right basically ligase doesn't stick stuff together like i don't know any other way to say it but basically that's how you remember that dna ligase hooks the fragments together and you get uh one solid dna strand very cool all right so now one last enzyme that we got to talk about is the topoisomerase right like basically helicase unwinds your dna right it's usually twisted and turned helicase unwind it and splits it apart right but on the other end this part is going to get even more twisted right so basically this really twisted part is kind of problematic right if you build up that much strain something's gonna break so basically another enzyme comes in called top of isomerase and that basically lets out all the strain here and it makes it straight again and then lastly there are things called single stranded binding proteins ssbs and all they do they just keep it apart right single strand they keep them at single strands prevent them from coming back together and hydrogen bonding very cool all right one last note on dna replication right we saw that like if you start with a strand like this right you're basically what happened is these two strands split apart right you got one over here you got one over here and essentially you make another one with a different colorless to represent new you make a new fragment right here you make a new strand there and you make a new strand there and you got a new two new of the identical dna molecule right so this method right here where basically some of these strands are fully old and some of these fans are fully new it's called semiconservative right you consider some of it but you make some of it so this is called semi-conservative now i'll just show you the diagrams for the other two right the other two that they basically disproved are the conservative one where basically the original strand is completely intact and then they create a completely new one that's separate from the original right this is called conservative because the original is conserved and then the other one is called dispersive and basically all this means that the two new strands are just like random combinations of the previous two so it disperses it and it's kind of hard to draw but dang it let's see if we can epic our drawing skills okay nice nice very cool and then just pretend that it's duplicated because that was too hard to draw god dang it basically the way they proved this is they basically labeled the new dna strands with some radioactive isotope and they basically saw which parts were radioactive or how how much radioactivity were in the new dna strands all right so we have this epic genetic code just hanging out in our cell right and now we're going to actually use it so how are we going to use it well basically the idea is in the central dogma right that basically says that dna codes for mrna okay so essentially you take one of the strands you copy an mrna from it and then that goes and creates protein so this is basically the essential dopamine right and essentially the process where you create mrna is called transcription and the part where we create protein from mrna is called translation and the reason why everything literally everything about your body is determined by your genetic code is because literally everything that's done by your body is done by proteins right so essentially your genetic code determines the structure of your proteins so that means that determines how your proteins determine how you look or like everything like literally how you behave everything it's german biogenetic code so let us dive deeper into each one of these okay transcription so we basically split up our dna right we basically have this dna strand let's say it's five prime three prime and basically all that happens is this boy called rna polymerase basically it gets over here and it basically just makes an rna strand right and then this rna strand goes out here and it leaves the nucleus right your dna is in the nucleus so it goes into the nucleus to make the mrna and then the mrna leaves the nucleus in order to make protein so why don't we do some base pairing practice huh so let's say that this guy was like a a g c t a pause the video and check if you could do the other one i'm kidding you don't have to pause the video so this one what's the opposite of a t right no it's not t get roasted mrna is troll and i have u instead of t don't do that okay u u c g uh a u alright so essentially you can see that like this strand is opposite of this strand so this guy at the bottom is called the template string however your dna started off as a double stranded thing so what is the top strand called well this guy is going to be tt c g a t and this guy is called the coding strand right because it's literally the exact same as the mrna so what's on this is going to be encoded in the mrna just with use instead of t coding string all right so now between transcription and translation this beautiful red mrna boy we had let's draw him goes under a few modifications okay so basically the first thing that happens is they add something called the five prime cap okay so that's just a modified guanine it's just called the bicone cap not very important but just know that it exists and then on the other end they add something called the poly a tail okay poly a tail which as you might expect it's just a bunch of a's okay yeah so it basically just protects the mrna as it's going from the nucleus to the cytosol where it will be translated into protein by ribosome but another very important thing that happens to rna right is that genes are really really big okay but proteins are not as big as the mrna transfer okay so your original mrna might be this really really really really really long thing right but basically only part of it is actually useful so essentially there are parts called introns and there are parts called exons now introns are like intrusive right they don't actually contribute to the protein shape so essentially a thing called the spliceosome basically cuts these boys out so now there's these exons get created and then it basically jams these two guys together now the reason why the body does it's like you would be like why the heck does it have all this random space is just going to get cut out by a splice itself that doesn't make any sense well the reason for that is because you could cut out different parts of the thing and it'll create different proteins right like if i cut out that thing at an intron i might make one protein like this but one time that i treated this guy as an exon now i get a completely different protein just by using these two parts so that is called alternative rna splicing and that is a pretty important point you have to remember that the reason why there is introns is because you could alternatively rna spicer right you could swipe it in different places make different proteins that's why our genetic code could be really really small but still make tons of protein all right so now our beautiful uh mrna all right so now our beautiful mrna which is no longer a pre-mrna transcript right that was right after it comes out now it's been modified it's been like put into the exact form that it's gonna be translated in and then it goes to the beautiful ribosomes okay so now we're at the ribosome so basically a ribosome just binds to this like a cool kid there's a small subunit on the bottom there's a large subunit on the top right and essentially there are three sites okay so before we explain how the ribosome works let's first talk about how the stuff on the mrna is translated into a protein okay so you know the proteins are made out of what amino acids okay so now we have to make amino acids from this like nucleo nucleic acid right so nucleic acids on the other hand are made up of lettuce so the way they code for them is that every three letters counts as a specific amino acid so let's say your mrna read this right then it's codes for methionine okay so your ribosome just looks at that and it's like oh wow there's an aug so that means i should put a methionine here incidentally the aeg is also the start codon so these triplets are called codons right and basically the start codon is where your ribosome starts creating the protein all right so this ribosome basically has three parts an a site a p site and an e site so eastside's the exit site right you have trnas which have like a protein right so this is a trna that's dragging the protein amino acid over right then you got a trna in here which has the current protein that we've already started making right it has a bunch of amino acids already then the a site is reading the next codon that's right here right this triplet that has like aug it might have like cga or something like that and that basically codes one of the 20 amino acids so basically what happens is that these trnas actually have like a thing right here called an anticodon so basically what do you think an anticodon does it basically binds over to this thing so basically the trna fits in here it binds over there and it's like oh so this is the protein i was supposed to bring right if i bind to this i should have put my current amino acid i just put that in the protein we're building essentially you have this you basically put this guy on here then this guy moves over here and voila you get a longer amino acid chain and you get a bigger protein so this guy shifts over there so now you have this guy and you have an even longer protein going all the way over here and now this is open the rna moves over and now you're reading the next set of three codons and eventually you reach one of three stop codons and that tells you to stop translating now that was like a very very dumbed down explanation and it was very confusing explanation so the one thing you have to remember about translation if you didn't understand any of that okay is just that every three base pairs every three like letters in the rna code for one amino acid right so essentially if you have like 27 um base pairs right that translates to how many amino acids right every amino acid is three and three uh base pairs so this translates to nine amino acids and then just applying this right like obviously the ribosome is gonna read every three and then it's gonna put in the appropriate amino acid with the help of trna okay really like like seriously knowing the detail the translation is not that important like they're not gonna ask you about that just know how the codon system works right you basically have aeg as your start codon there are like 60 other codons right that code for other amino acids and then there are three stop codons all right so that is all you got to know about translation now just like another distinction between prokaryotes and eukaryotes you guys know that prokaryotes have no nucleus right so basically your dna up here and your ribosomes are literally right there so essentially when you make your rna the rna could immediately go into a ribosome and start making a protein at the same time so it's kind of crazy but in eukaryotes it's kind of different because you have a nucleus your mrna gets in here it gets out of the thing and then it could go into a ribosome which then gets translated so in prokaryotes it's all together in eukaryotes it's separated by the nuclear membrane okay all right so you know that your body does not always do the exact same thing right like when you're hot you start sweating when you're like i don't know basically basically your body has to respond to different things right you have to regulate what genes are expressed in different environments and obviously different cells like express different genes right like your nerve cells are completely different from your muscle cells right so what creates the difference they all have the exact same genetic code but the differences in which genes are expressed so basically the way it works in like the nucleus right they're basically a bunch of dna right now some of the dna is really condensed some of it's like really loopy and it's free and it's not condensed at all so basically the dna that's free is really easy to transcribe right so so those are the genes that are going to be expressed more so how do we regulate the coiling of the dna so let us look a little bit closer basically dna is coiled around these things called histones right so basically there's eight histones per block histones and basically each blob is called a nucleosome okay and basically the histones are what keep the dna really really coiled okay so essentially if we add stuff to the histones it changes how close it is and how easy it is to express right so if it's super coiled it's not easy to express so how do we make it more coiled if we want to deactivate a gene we just add a methyl group okay so methylation equals deactivation and then the other one is acetylation right that's basically if you add an acetyl group so i think it is like that basically acetylation is activation so the two things you gotta remember is the more coiled the less activated and methylation causes deactivation right so methylation basically causes it to be more coiled acetylation makes it less coil so it makes it more easy to transcribe and express it now the other way to regulate stuff is something called an operon right so basically during transcription your rna polymerase binds to this dna strand right so your rna polymerase binds it creates the mrna and the mrna goes away and does the stuff so if we can regulate when the rna polymerase does stuff then we could regulate how much protein is created right so basically the operon is made up of a couple parts so the first part is called the promoter okay so that is basically the part that the rna polymerase binds to then it could be followed by something called an operator so as you might expect right the operator is what lets you prevent rna polymerase from binding so literally if something called a repressor right that's called the repressor binds to the operator then rna polymerase even if it's here it can't go through the repressor so basically if you bind to the operator you prevent the rna polymerase from like landing and basically like the operons control a bunch of genes over here right so essentially if we could stop the um rna polymerase from passing this point it basically prevents all these genes from being expressed alternatively right if you don't want to repress it well i'm going to activate it right like by default it's not expressed that much but once you want to actually express it more then there is another thing called a activator right activator that basically provides a place for rna polymerase to bind right so now our nickel and red wants to bind this guy so it comes down here it's attracted to that guy and then it goes over here after we do the dust like really hot okay that that's kind of why the rna polymerase doesn't want to hang out you know what i'm saying and then they're not as important but basically there's a region called enhancer not as important but what is important is that things called transcription factors can bind there and they can regulate how much the genes are being expressed so transcription factors are pretty important know that they regulate transcription right it makes sense transcription factors regulate transcription all right so just to give a more concrete example let us talk about the lac operon right so we have our dna right and basically this lac operon codes for stuff that metabolizes lactose right so logically right if there is lactose in our body we want to make the enzymes to like metabolize it so this is in bacteria by the way so essentially what happens in the lac operon is by default a repressor binds to the operator right and that basically prevents any of these genes from being expressed however when lactose is in your body it creates something called aloe lactose and aloe lactose bind to the repressor and it causes it to leave okay it causes it to like dissociate from the operator so when this leaves right now the rna polymerase could transcribe all these genes and hooray you got all your enzymes for metabolizing lactose when you have lactose and you don't have it when you don't have lactose so it makes sense this one this operon is really really important okay so just understand like the basics of how it works like your book might go into all these like random stuff like black z black why it does this like if the inducer code represents or all that nonsense just remember that by default it's repressed and then when lactose comes aloe lactose binds it and it stops repressing it just if you wanted to know aloe alolactose because it causes the gene to be expressed it's called an inducer an inducer is something that binds to a repressor or an activator and like causes the gene to express the opposite is that's called the coverpress okay all right so now the next thing we gotta talk about are mutations okay so basically all mutations are they're just random changes right so essentially like you might have like an a t c g and this just by chance right just just by chance it basically accidentally binds a c to an a instead of a t so now you have c a g c and now this new genetic code will create a completely different protein right one amino acid is enough to change the structure of a protein completely and then as you got no natural selection add some variation and basically these random changes now gives natural selection something to act on if everybody had the exact same code how would someone be more fit than someone else the reason why people are different fitnesses is because there's slight deviation due to errors in dna replication and other stuff okay so why don't we talk about like the two most important types of mutation right so there's point mutations where you just change uh t to a c right like just in one place point mutation but then there's also those things where like somehow an entire base pair gets deleted and now you're kind of screwed because basically let us say that you have like um instead of atcg it just puts agc so this is our new thing so let's say we continue it over here originally our protein would like group it into three like this right but now if we make it different it's grouping this d3 together instead of cag it's an agc so essentially everything after this is going to be completely messed up because you're changing your reading frame right if you can delete one thing everything else gets shifted over and that means that your your all your amino acids are going to be affected so basically a deletion is called a frameshift mutation basically any mutation like an addition or deletion that causes your groups of three to change is basically a frame shift because you're changing completely which amino acid so basically there's things called mutagens and carcinogens right those are the things that cause mutation right like sunlight is an example of a carcinogen or mutagen right because basically in sunlight your cells form thymine diameters which causes air then dna replication which causes mutations which eventually could lead to cancer right skin cancer is caused by the sun so that is how a mutations arise now there's one other type of mutation right there's aneuploidy and we kind of already touched on this in our um in the meiosis video but basically aneuploidy just if you have the wrong number of chromosomes down syndrome is trisomy 21 right you have 321 chromosomes instead of two now let's just talk briefly about natural selection right i think we'll cover it a bit more in the next one when we talk about charles darwin and stuff i think but basically natural selection and basically the guys who have the best genes survive right and if the guys who survive have better genes they pass it on to their offspring so your offspring also have better genes so overall as you as time progresses you're going to keep getting better g now the problem with this right is that if everybody's the same everybody's going to die at the same rate so everybody's just going to keep having the same genes and you're never going to get better genes the way natural selection works is that like one guy gets a better gene so let's say this guy got the better gene then he's the guy who's going to survive everybody else is going to die and he's going to pass on that gene to all this kid so basically the whole point of mutation is so that you could have natural selection and eventually these really good genes are going to accumulate and if it's bad that guy is going to die so that's not going to pass on to the next generation but then we ask how do bacteria generate genetic diversity and that is actually kind of complicated right there's basically a bunch of ways they do it even though they don't do sexual reproduction right like bacteria or exact clones of themselves minus like point mutations that are caused by x-rays or something so basically the three ways that bacteria generate genetic diversity are transduction transformation and conjugation now conjugate is the most fun one because that's basically where they stick each other with pylon and then they transfer dna to each other directly right if you have two bacteria they just give each other a nice little smooch and they pass genes from each other then transformation right like it kind of made sense you basically take in genes from your environment they're just floating around and you're in your own genome transformed right so that's just like dna getting heated into there now transduction right you're taking it from one guy to another right transduction you're moving it from one guy to another so essentially what happens is a virus infects this guy and like unintentionally the same virus infects another guy and then the genomes get moved from one bacteria to another okay and now for the last topic in this unit it's just biotechnology this is pretty straightforward so the first biotechnology thing they talk about in the books is your gene cloning right so essentially if let's say let's say we have a gene this red gene that we want to clone and we don't know how to clone it right like we we don't have the tools personally to clone it well what we could do is we could put it in a bacteria and have a clone for us that's how we do we just make other people do the work very cool so essentially what scientists do is they take restriction enzymes and they cut it at specific places right and if you look really closely the ends of the chromosome look like this right and then there's a couple parts it cuts unevenly right so now there's this region over here that has base pairs and this is called the sticky region so then you use the same restriction enzymes to cut this gun so restriction ends uncut and they make sticky ends and now you have the same idea over here so there's like that and there's like that and basically this guy could fit in there perfectly right so now we have our new bacteria thing with the red stuff in it and now whenever the bacteria reproduces they're reproducing arginine too very cool thank you bacteria thank you for helping us out now the next one is pcr right polymer race chain reaction and basically the point of this dude is that we have one strand of dna how do we make it into a ton of them and basically just human done dna replication okay so basically you chuck in a bunch of rna primers right you chuck in some dna polymerase right you chuck it in there so basically the first step is to heat it up right and that causes the dna to split up right then what happens is that these primers go in and they latch on over here and then the dna polymerase goes and extends it and now you have these other dna strands and right now you have two of these dna strands and basically you keep repeating the cycle you heat it up you split it apart you have the primers attached you elongate it and then you and then hooray you have two new things and you can repeat it over and over again and it keeps increasing exponentially so that is how pcr works then there is also gel electrophoresis so basically the point of that is you basically have the gel okay right gel electrophoresis if you have a gel and you basically have negative dna right or some like charred molecule over here so let's say we put a positive charge here and a negative charge here and the dna is negatively charged then guess which way it's going to go it's going to go this way but it's the gel so the longer molecules actually move a lot slower so after some time you basically get to see a bunch of lines so you might see like lines here you might see lines there and basically all of these guys have the same length because they travel the same length then these guys have the same length but they travel the same distance and these guys have the same length because they travel the same distance so essentially we could measure how much of each length there is or we can measure what length of dna there are like one thing they do is they basically cut up like a random prism's dna and they run it through a gel and basically each brilliant has a unique thing right because if you cut the dna it's always going to be a unique like um set of cuts right so definitely each rhythm is going to have a unique gel right you're going to have a unique set of bars and then the last one is dna sequencing so the way they do it now is something called shotgun sequencing right and this is also called next-gen sequencing and basically what they do is they really just cut up a bunch of dna they pcr it they like sequence every single one of those strands and then once you sequence each of those strands then you could like use a computer to align them and then you get the whole thing but basically how they did it in the olden days is they basically had like let's say that this is your dna sequence you want basically they have these terminating uh they're called dntps and they're basically like fluorescent um probe and basically they end the sequence so you can have like a ender a you could have an ender t you could have an end or c and you could have an energy and this is not like chain termination didioxy sequencing or something i forgot the entire name but basically the idea is it starts transcribing right you got a c t g and the first one might end with the t right so it just ends at the t nothing could be added after so you have t somewhere then this guy will it'll put like a normal t and it'll put a chain terminator g and now you have a t g right and then it'll do a t normal g and then a chain terminator a t g a and then basically you have a t g normal a chain terminated c and now you got a t g a c so now why do we run these dudes through jump so the t is the smallest so it's going to get the farthest right then your tg is going to get the next farthest then our tga is going to get the next virus and then our tgac is going to get the next farthest and basically each of these is colored a different fluorescent color so we know the color of the first line is the color of our first nucleotide so we know that's the color of t this is going to be the color g this is going to be the color of a and this is the color of c anyway we know the sequence of our dna very happy now like recently they had even more advancements they literally run the dna through like uh nanopore and basically based on the electrical disturbances of the nanopore they could determine the sequence i have no idea how it works pretty cool stuff all right thank you guys so much for watching i hope it was helpful as always if you enjoyed the video leave a like and subscribe for more this was a pretty massive chapter i don't know whether i did it justice but let me know down in the comments if there's anything i missed and hopefully i can make another video on it or something but anyways thank you guys ever for watching again and see you guys next time