DIP Episode 64 - Cell Biology For The USMLE Step 1 (Part 3)

Okay, welcome. My name is a divine. I am a PGOI one a transitional year resident going into radiology and this will be episode number 64 of the divine intervention podcasts We're going to continue our discussion of cell biology as relevant to the USMEL Step 1 exam This will be the third part of this podcast and this is a continuation of episodes 56 and 57 Which I essentially parts one and two of our cell biology discussion So today we're going to continue talking about cell biology again Believe it or not. This is very high Yoda for step one. So the first thing we'll start with is a Since we've sort of talked about our application and all that stuff sort of makes sense to talk about transcription, right? And I mean obviously transcription is the process of going from From DNA to RNA, right? I mean there are multiple kinds of RNA as we'll talk about later like mRNA, TRNA, RNA, RNA, SNR, and HN RNA would define what all those things mean in a bit and Key thing you want to remember just like for replication. We had the any polymeries being the go-to guy The go-to guy for transcription is RNA polymeries, okay? And basically its job, right? It's to bind to a promoter region, right? And then it basically begins a stature transcribing the RNA from a DNA at that point, okay? I just said that it binds to a promoter region.

So if there's a promoter region on a DNA It probably makes sense that there's a terminator region as well where you stop a transcribing off from and Remember that this promoter region that RNA polymeries binds to that promoter region is actually not transcribed So they can very easily make this again Whether you like it or not you're gonna say like genetic Experiment like questions on your exam, right? So they can give you like a DNA sequence, right? And label a region as the promoter, right? And then they try to get you to pick out like what the mRNA will look like As answer choices just remember that the promoter is not Transcribed so it's not part of the transcript the RNA transcript that's meet from from DNA And then one other thing I want you to remember is that In replication right to you basically use both DNA strands in the process of replication both of them serve as templates But in transcription things are actually significantly different, right? So DNA is doubles at least in human bins right? DNA is double stranded Remember right if you want to think about a single stranded DNA organism Hopefully that rings bells of Pover virus B19 actually is kind of high you to another first step one. Okay, so back to our story, right?

So We have double stranded DNA the thing is with respect to transcription We have one strand of that DNA being known as the template strand That's the strand that's gonna be copied in the production of mRNA And then your other strand is known as the coding strand the coding strand is not copied Very high old it's not copied in the production of mRNA So there's a template strand. That's the one that's copied to make our mRNA There's the coding strand that is not copied to make mRNA and it's actually kind of interesting right to realize that if DNA is double stranded and anti-parallel It should then make sense from what I just defined that the mRNA you're producing right has to probably have Pretty much the same sequence as the coding strand the coding DNA strand although Because it's RNA instead of having a T right like a thymine it should have a U Urself, okay? Again very high you to know that and again remember that the DNA will also be reading the 3 prime to 5 prime direction And the RNA the mRNA that's been synthesized is gonna be synthesized in the 5 prime to 3 prime direction right And I mean again, like I said there are many kinds of RNA. There's like mRNA. There's RRNA There's tyranny. There's SNRNA. There's M I RNA and all that stuff Although the most common most abundant in the body at least in general for step one if you're comparing like the big four between like mRNA, tyranny, R RNA and SNRNA R RNA is the most abundant.

I know kind of shocking So I I think it probably makes sense again. I love the way we've been we've been doing a lot of uh Compend contrast Between prokaryotes and eukaryotes or this process versus that process because in companion contrasting things like I said in that podcast about the central dogmo You can actually get some very key nitty-gritty details down path. So Let's talk about differences between transcription and I mean Let's talk about like transcription all differences for prokaryotes versus eukaryotes, right? So the thing is in prokaryotes there is only one RNA polymerase makes life easy, right? But reukaryotes were more complex organisms, right? So things should probably be a little more complex with us And it so happens that there are three kinds of RNA polymerase In eukaryotes, right? At least the high old ones you need to know for your test, right? There's RNA polymerase one RNA polymerase two and RNA polymerase three And unfortunately for you you actually do need to know who the kind of RNA that is made by each kind of RNA polymerase You see oh divine come on. There is absolutely no way this is high of first step one Well, you can see me laughing sarcastically. I think you should know what that means already. So There is a no money though that I've always used that as always made it super easy to remember It's just remembering the word remit R-E-M-I-T, okay? So it's like remitting money to someone, right?

Remitting money to the government every year when you're paying your taxes for example So remits is R-E-M-I-T. So just take um the first letter R Skip the next letter go to the next letter M Skip the next letter go to the last letter T and then above those letters put one two three and Just like that you already know what RNA pull one pull two and pull three two so RNA pull one makes R RNA RNA pull two makes M RNA RNA pull three makes T RNA if you remember that alone you should be good to go for your test although There's a little one kin as thrown in right so like your SN RNA that helps you with splicing is actually made by RNA polymerase two and Your five S are RNA is actually made by RNA polymerase three. I know it's kind of annoying, right? But Just remember remit Put a one two three over R-M-T and then RNA pull one makes R-R-E-N RNA pull two makes M-R-E-N RNA pull three makes T-R-E-N right and then your five S are RNA is made by um by RNA pull three and then your small nuclear RNA right that helps you with um, you know splicing is made by RNA pull two Right, but I think those that lower you details the remits one two three should probably help you answer like 99% of the questions you see on that concept not a hundred percent 99% So and don't forget that our R-R-N is actually meeting the nucleus again. I promise you these are not low your details so um For procaryotes, right?

So the thing is if you want to begin Transcription if you want to bring RNA polymerase to like where it like the promoter where it's supposed to do its job You need someone to sort of draw RNA polymerase in In procaryotes the thing that draws RNA polymerase in is known as sigma factor, right? In eukaryotes there's most socially in a sigma factor Um, we have things more we have things like transcription factors There are multiple kinds of transcription factors and you don't need to memorize them But there are a few high yield things you kind of want to know right? So for example, uh One pretty nice thing you can sort of keep in mind here is There are some transcription factors. I guess bringing in some from a ecological integration here. There are some transcription factors known as p-par transcription factors, right? So like peroxysm proliferate proliferator activated receptor, right? And there are many kinds of these receptors But the key was that matter for the usml is a p-par alpha and p-par gamma, okay? p-par alpha is a transcription factor p-par gamma is also a transcription factor And the thing is those transcription factors, right? um um They sort of work on like intracellular receptors kind of like your steroids, right? But remember for p-par alpha, right? It's uh p-par alpha the transcription factor is activated by um By uh certain drugs, right?

Like your diabetes meds your um I mean sorry your anti-lippida meds uh your Fibrates like gem fiber zil phenofibrate chlorfibrate and then p-par gamma is activated by your diabetes Medications your tzds your fersolidine diodes, right? Like um like rosy gliderzone, pio gliderzone, Troglyderzone and all that fun stuff So the thing is p-par alpha is a transcription factor for many proteins Like I mean I guess like many genes that ultimately help you proteins that that ultimately help you make proteins that are in Volved in like the breakdown of fatty acids um The utilization of fatty acids the optic of fatty acids by depo sites. So basically These fatty acids and triglycerides you can increase the occurrence by activating p-par alpha, right? So This should explain why your fibrates, right? One of your key anti-lippid medications actually the best are reducing triglycerides That should kind of explain how it works For p-par gamma the thing is p-par gamma, right? Is a again, it's a transcription factor and the thing is it's a transcription factor for many genes that Give rights to proteins that essentially help you sequester fatty acids in a depo sites So you may say but divine How's this helpful if you have diabetes? Well actually let me explain what the thing is Fatty acids, right? triglycerides and all that stuff they are all stored by a depo sites Believe it or not There are many cells in the body that can actually use Fat as their main source of fuel, right?

But the thing is if all that fat and all your triglycerides are all sequestered in a depo sites, right? Then they are no longer available to be used by order organs of the body So other organs of the body begin to like depend More and more on glucose and if the organs of your body I depend more and more on glucose They're increasing your utilization of glucose you're essentially clearing your plasma your bloodstream of glucose, right? You're essentially raising your insulin sensitivity That's how the p-par gamma again is like your tzds work in treating diabetes Okay, so and then Next differentiation between prokaryotes and eukaryotes with respect to transcription is that prokaryotes, right? If you want to sort of stop transcription You can use like some fancy things known as like stem loops and then there's something known as like row factor that helps you Stop transcription in in prokaryotes in eukaryotes. There's no row factor. I probably won't worry about that beyond that point and then It's actually kind of high you to know some pharmacology associated with RNA polymerase, right? So for example if you're looking at prokaryotes, right? The thing is bacterial RNA polymerase, right? Can actually be inhibited by a bunch of drugs, right? But probably the poster child one you want to remember for your test is rifampine, right? Remember rifampine constitutes a part of the right predium in for TB, right? Like rifampine, isonize it, pierceinamide and ethanbutyl.

The way rifampine works Is that it's an RNA polymerase inhibitor and please do not forget all the high-yelthings about rifampine, right? rifampine Is actually used as prophylaxis in meningitis, right? So let's assume you've been of close contact of people that have a meningitis Like my cereal meningitis. You can actually prophylax Basically like do like a chemo prophylaxis with rifampine and there are actually three drugs total that you can use for Nysero meningitis chemo prophylaxis. You can use rifampine You can use septriaxone. Remember septriaxone is the drug of choice for the empiritrymen of meningitis, uh, uh, uh, uh, Nysero meningitis and then you can also use ciprofloxacin But of all those three the preferred agent is rifampine. So this is more for like for the future if you're taking step two or step three Well, if you're listening to this podcast, prepare for step one You you cannot become a doctor if you don't take step two or three So I guess you might as well just learn it now.

The thing is your friends at the mbm Love writing questions where they put answers that are can all do the same thing If you see rifampine if you see cipro and you see septriaxone all as answers for chemo prophylaxis against Nysero meningitis You want to go ahead and pick rifampine rifampine is actually the preferred agent and the reason they will do that kind of question is Many people don't think of rifampine outside the realm of TB right so people like There's no way this can be the preferred agent. Well, Nysflash it is okay. So this one of those rare things you want to keep in your mind for the future and then also don't forget that uh uh Uh rifampine right it revs upside to crumb p450 right so let's assume a patient has been on birth control for a long time They've never got impregnant and then the contract TB and then they become pregnant right to probably want to think of those people as oh They took rifampine well Sorry, you revved upside to crumb p450 increase the metabolism of the breath control the OC Ps were taken and then they became a not effective basically And then also don't forget that rifampine makes all your secretions orange you wouldn't like your tears kind of scary though.

Okay now um another high-yield uh And I guess um Just another high-yield thing that shows up on tests Uh just like I said that rifampine helps you pro chemo profile acts against uh I assume it is if you're close contact just and though Similar concept we love to test is if you're close contact of a person that has a pertosis right Uh how do you want to chemo profile act so that you don't get pertosis that's actually with herithromycin right remember That's a macrolead uh it's not related to this concept but I just thought I should mention it uh Right here though uh with rhomycin probably come up in the next podcast when we talk about uh Translation right because uh all those are protein synthesis inhibitors target many steps in that process And then let's assume you're an alcoholic and again we're still talking about pro-charyotic uh are any polymerase Let's assume you're an alcoholic and your liver explodes right if your liver explodes Well you cannot clear a morning anymore you can't clear a morning anymore because uh you can't do your recycle anymore Well uh money will be going to build up and the money does a lot of bathrooms right It basically like messes up your brain right that's the whole business behind a heparic and cephalopathy But the thing is uh it's not just you that uh can make ammonia from processes in the body bacteria in your gut Guess what you can also make ammonia right so the thing is if you have uh Cereosis right you want to sort of like kill every source of ammonia in your body possible right You can use lactulose already explain the mechanism behind the lactulose for that process in a previous podcast But one of the things you can actually do is give a drug known as refaxi-min okay refaxi-min refaxi-min I think in the hospital it's known as uh Xivaxan or something like that it's used a lot in the ICU As it so happens I'm on an ICU rotation righ

t now, but that's a different story But refaxi-min inhibits RNA polymerase Uh but the good thing about refaxi-min is kind of like taken by coma-cin orally It's not the bioavailability is horrible right so it stays in the gut It stays in the gut and basically nukes your entire GI flora and by doing that You're basically nukin a source of ammonia because your GI flora are very important source of ammonia in your in your body Right so if you kill off all that GI flora you're killing off a source of ammonia production And you can actually use refaxi-min as treatment for hepatic insaphylopathy only problem is it's super expensive, but Um, it's actually been shown by studies to work as well Or probably even better than lactulose in the treatment of hepatic insaphylopathy Okay, and then if you're looking at RNA polymerase from the standpoint of uh Eukaryotes um, there's this drug that used to treat like childhood cancers right like ewincer coma um Wilms tumors bloody bloody bloody blood That's all done by uh actinomycin D right remember actinomycin D is a cancer made in inhibits RNA polymerase in Eukaryotes Um, and then um for those of you that love mushrooms uh, don't forget to this uh thin uh, it's known as alpha-minitin I think it's found in like some mushrooms.

I think they're called like death mushrooms or whatever. I never eat mushrooms um But alpha-minitin it's found in certain kinds of mushrooms um If you consume that alpha-minitin I mean if you consume those mushrooms you consume the alpha-minitin You would inhibit your Eukaryotic RNA polymerase and your liver will basically explode Okay, so you should probably not consume those mushrooms right so that uh, you don't require liver transplant The thing is uh, there are many things that can support your heart Support your lungs support your kidneys if those organs have failed There are very few things that can support the liver the liver is just one of those organs that uh, well a lot more high yield than people give it credit for okay So please do not consume mushrooms that contain alpha-minitin Uh, would like you to live a lot longer than uh, what you will if you consume the that mushroom So now that we've talked about those are differences in transcription between pro-currier to Eukaryotes, right? Um, remember that after transcription you make um mRNA right or whatever kind of RNA you're dealing with and then um, at least in the case of mRNA in Eukaryotes uh, that mRNA is sent out of the nucleus, right?

And then it gets married to the ribosome and then you translate that uh, mRNA and mRNA and uh, make up protein um, but remember that uh They actually in Eukaryotes, there are certain steps in the process between transcription and translation Not so for pro-curriotes in pro-curriotes translation is actually quote transcriptional so as transcription is happening The ribosomes because remember right you pro-curriotes um uh ribosomes can immediately jump on uh on the mRNA and begin to translate it to uh to protein And I guess let's Well, I guess this probably makes some sense it probably makes sense to sort of talk about a pro-curriotic transcription on its own, right? The thing is um In transcription with pro-curriotes and I mean some of these commonalities will also be held by Eukaryotic transcription, but the thing is um there actually um Certain regions on the mRNA, right that you uh That you make that are known as um on translated regions Um, and those on translated regions, I mean there's uh, there's a bunch of stuff that goes on with those things, right? So they are called on translated regions. They are not called on transcripted regions, right? So the parts of DNA they will be made into art they'll be Transcribed made into the mRNA, but you wouldn't make the away to the final um to the final um polypeptide sequence you're making after being attacked by uh my ribosomes, okay? So they're not in the final amino acid as sequence, right?

So again, they're on translated not on transcripted, right? So they're on translated regions at the five prime end and at the three prime end And there's actually some fun stuff at the on translated regions, right? Like at for example at the five prime on translated region That's where you'll find the seven method on one of the same capital talk about that in a bit And for prokaryotes, right? Again um You make some you make uh in prokaryotes you can find something known as a police is chronic mRNA So basically just means that that mRNA contains like the The gene products of like multiple genes, okay? versus your karyotes that are mostly like monosyschronic, right? So uh basically it's like you You transcribe one gene you make one mRNA and that mRNA is attached to only one gene, right? versus prokaryotes where the mRNA can contain um RNA products of multiple genes, right? So like polysystronic and the thing is in In um prokaryotes, they actually know there are actually no introns in the mRNA transcript for you prokaryotes, right? versus your karyotes that contain exons that are expressed and introns that are in the way, right? But for prokaryotes you just have exons, right? You don't have any introns And again, I already said that translation in prokaryotes is a quote transcriptional and um The thing is in prokaryotes, right?

That you see that fancy five-prime on translated region I talked about It also contains the shine dalgano sequence again the shine dalgano sequence It's a part of the five-prime on translated region. That's actually where one of the ribosomo subunits actually binds To begin the process of a translation and I'll talk about that process in a bit Now remember the polypeptide that's made, right? It's made from the The amino ends to the carboxy end. Just one of those bizarre things. We don't know it or you don't know it But it definitely does show up on examples And then if we're looking at the process of eukaryotic transcription, right? Just like we had a promoter in prokaryotes. We also have promoters in eukaryotes And remember that promoter actually has like certain high yield things right so like the carbox I think they call it like the C80 box as well There's also the tada box, right? Those are all found within the promoter region and again very high you to know this The promoter region is not transcribed, okay? It is not transcribed, okay? It's basically like a gathering place.

I sort of think of it as like Nursing sign out in the morning before the nurses go about their their daily business or I guess physicians as well Right, they have sign out right so they sort of congregate at one spot and then they go about their daily business That congregation spot before you go off about your business of transcription is the promoter region Um, and the thing is I remember I said that in prokaryotes, right? The you could have like polysistronic mRNA and that polysistronic mRNA You sort of all start everything at one promoter um for Eukaryotes You have a promoter for every gene that you transcribe, okay? versus for prokaryotes where you can have multiple genes and they'll only have one promoter Right because you're producing a polysistronic mRNA transcript and again, there are exons and introns in Eukaryotes In Eukaryodica mRNA transcripts. There are no introns in prokaryodica mRNA transcripts And then Um, the thing is RNA processing is something that happens a lot in Eukaryotes doesn't really happen much in prokaryotes Right, so if you're thinking about RNA processing Think mostly of Eukaryotes and I mean there's just three big things you want to know about RNA processing right? There's like the addition of the seven method one or send cap That's actually something that is uh That is uh Code transcriptional and actually happens at the same time as a transcription is going on You add that seven method one or send cap.

It basically sort of serves to go to purposes right? So one purposes the thing is the cytosol is a rough neighborhood Right, so to protect yourself in that rough neighborhood That seven method one or send cap is sort of there to protect the mRNA transcript from being degraded But another thing is ribosomes for them to say like oh wait uh Are you mRNA for them to be able to identify mRNA? The actually need that seven method one or send cap is actually kind of useful for that purpose and then um Uh One of the processing event that happens is something known as polyadenolition right Uh, and that happens at the three prime end right and remember I said that the addition of the seven method one or send cap is Co-transcriptional event so it happens at the same time as as transcription Actually the addition of the polyatil is uh post transcriptional event It happens after transcription has happened very high you to know that and again that polyadenolation What does it do again?

It protects the mRNA transcript in the rough neighborhood of the cytosol but under thing it does is um It actually helps with pulling the mRNA out of the nucleus to going to the cytos uh cytosol for for translation And then the third processing event that happens is uh basically splicing right uh in splicing you remove those introns that are in the way Because they're not part of the final polypeptite sequence And remember that that whole process of splicing happens in something Uh, so an organ known as the splice us all okay. Just one of those bizarre things you want to know And then you want to know that they're certain you know things that make that process happen right There's like SNRN As That make that happen remember SNRN As are made by RNA polymerase two And then they're proteins known as SNRN Ps or SNURPS okay They also help with that process and the thing is in this process of splicing um there is something known as I'm not gonna tell you how it works there There is like a detailed mechanism about how this works But basically this is just a buzzword.

You just want to keep floating your brain for step one But if you ever hear a word like lariat intermediate just remember that that is something that happens in the process of splicing And the thing is believe it or not uh splicing is actually a kind of like a high yield process to understand and here's one thing Uh, I'll just tell you this uh should probably have added this to my central dogma of studying podcast The thing is this is probably more specific to medical students if you're ever learning any concept in med school You should always approach that concept the way first state approaches its chapters ask yourself for this concept Even if it's in genetics or in whatever it doesn't matter ask yourself is there relevant clinical and madden associated with this concept if there is learn it next question You ask yourself is there relevant clinical physiology associated with this concept if there is learn it And then the next question has yourself is there relevant clinical pathology or are there diseases that relate to this process if there is Learn it and then another thing is ask yourself Is there relevant clinical pharmacology that relates to this concept if there is Learn it if you can approach every concept you learn from this perspective you will make your learning slow But you'll make your learning rich and you can you you will be super super well prepared for step one If you approach learning from that from that standpoint As you see we'll talk about splicing in the context of certain kind of high yield things in fact I guess I can sort of do that right now, right again.

I said splicing happens only in your carriers um And the thing is splicing is basically a way where you can get like a one a two for one special right so it's like Oh, you took one gene you made one. I'm mRNA transcript But you're like hmm from that mRNA transcript. Can I get more than one protein product? You can do that by employing or process known as alternative splicing right Um, and basically it's it's a means that the body uses to just make many proteins from like only one gene, okay Um, and I mean these processes sort of occurring different cell types right so for example if you're trying to make if you're Sort of thinking about like i g m versus i g d the primary difference between i g m right remember It's a pentamer versus i g d is actually alternative splicing. That's how you get i g d from i g m um, and uh The different dopamine receptors right so you know that there is like multiple kinds of dopamine receptors They all made by alternative splicing Um the different proponents right so as you're studying cell biology or cardiology You probably talked about like the multiple kinds of troponins. Those are all made by alternative splicing remember We measure troponins.

It's one to diagnose the presence of a myocardial infarction Um, and but actually your friends at the mbmi are counting on you to sort of make uh wrong knowledge transfer Right so the thing is many people uh in fact i may have said this in a previous podcast when i was uh Probably when i was not paying much attention If you're looking at like ipo b 48 versus ipo b 100 Um, the differences between those two is actually not alternative splicing. Okay, it's super high you to know that it's not alternative splicing Uh, the difference in those two molecules is actually something known as uh RNA editing Um, it's just a specialized process that occurs in humans um, but i'm not gonna discuss it more than that But just remember ipo b 48 ipo b 100 it kind of sounds like oh alternative splicing may appear player. Everybody does not Okay, there's a lot of research that sort of says that is not the process that helps you produce ipo b 48 versus ipo b 100 that was the thought before but that is not the thought right now Uh, I mean there's some things I may say now that will probably be wrong in 50 years, right as more people discover more stuff Right, so I guess I should probably update these podcasts from from time to time.

Okay, and then again remember from transcription um, you make uh like uh mRNA transcript that mRNA transcript before processing Which are basically the processes have been discussing us so far uh before processing you have you basically have like pre mRNA Right, and then as you keep processing that uh mRNA you make like a hn RNA and then after that you make like your mature right like your mRNA that's ready to go and take over the world in the process of a translation And then to sort of like round this off. I guess I'll sort of say a few words about ribosomes and um, tRNA right so remember ribosomes in precarious There's like uh 50s and 30s they come together to form uh 70s, right? There's this whole sleuth of drugs that inhibit 50s This whole sleuth that inhibits uh 30s right so remember like the bi at 30 cell at 50 numonic right so like you amino glycosides like gentamysine and to bramycin Right, the inhibit the 30s arrival so your tetracycline right like Demeclocycline and all that stuff the inhibit the 30s arrivals of and then like clinda mysen Your linkosamites, um, erythro your macrolids uh, lenezolid and all that fun stuff the all work by inhibiting a chloramphenicol as well The all work by inhibiting the 50s ribosome right in procaryotes um, and the thing is um, let me see divine. How do I remember like 50s 30s 70s?

Just remember that those uh like uh 53 and 7 they are not divisible by two I don't know if that helps in any way uh versus your cariot right that have like 60s 40s and 80s uh the first numbers six for an each those are all divisible by two um And please don't forget right the 30s um Uh ribosome right so it's like the small ribosome subunit in procaryotes it actually has like a 16s subunit That 16s subunit is actually the thing that recognizes the shine dogernos sequence that you'll find at the five prime on translated region of mr.in um And um, yeah, I think that's all I'm gonna say there I mean I'm not worth in that immediately test from time to time is like oh for the large ribosome subunit in eukaryotes right so like the 60s subunit um Uh, that's where you have uh like certain subunits like five s r rna and five point e des and twine des And I mean the only reason I probably mentioned that is the five s r rna remember I said that all r rna is uh made by rna pull one with one exception the five s r rna that's actually made by rna polymer is uh rna polymer is three Okay, and then the 40s subunit of the ribosome is the thing that recognizes uh the uh So basically the 40s or uh small ribosome subunit in eukaryotes that's what actually recognizes the seven methyl guanosine cap to identify that's uh To identify the thing that comes behind it as a mr.in Uh, so that you can start a translation and then for t rna just key things you want to know you want another shape of t rna Right, uh, it's like a clover leaf shape that you should never get that wrong with an exam those at easy points And then don't remember don't forget that uh t rna has like a five prime end that has like a phosphate group right And then it has a three prime end that has a hydroxy group that three prime end is actually kind of high yield for certain reasons That three prime hydroxy line is actually the

region that uh amino acyl tyranny synthetize uh basically um Does some magic with so that you can add the activated amino acid to that region So again the three prime end um has like some cca residues very high yield to know that that can uh bind the activated amino acid and that activation and that process is sort of catalyzed by amino acyl tyranny synthetize Uh, then don't forget that your tyranny contains uh anti-codons right uh that bind to codons on uh on mr.in Right and then tyranny actually has like some like super weird basis right so like um Remember like in general rna contains uh your cell instead of finding right but you can see like some weird teeth in tyranny So don't forget teen the teen tyranny for like a weird tea okay So you may see like some weird basis in tyranny So I think this podcast has probably gone on for long enough Um, so I will uh make uh probably like two more cell biology podcasts.

That's all I'm gonna focus on until I'm done with it So I wish all the best. I hope the leakers wind you're getting tomorrow Uh, I'm not necessarily a leakers fan. I'm a libron fan. I was a caps fan before but um Uh, now I guess I'm a leakers fan and thankfully they've been doing pretty well Overly they meet the playoffs and uh win the western conference and then uh win the mb championship We'll see how that happens up. I mean, I will definitely be praying for that and then I just also want to advertise uh um That I offer private one on one tutoring for the usml step one step two and step three exams, okay? And also the medicine in training exam Um, and probably I guess the medicine boards um, I'll probably make some podcasts in the future That explain why I can offer tutoring for the medicine boards even if I'm not going into internal medicine Um, I'll talk about that in the leader podcast and I also I guess offer tutoring for organic chemistry But I guess that's more relevant to pre-meds if you have a pre-med brother or sister or whatever Organic chemistry is also my specialty Um, that's one thing I uh still recall pretty well from uh from undergrad um And then I also do like interview prep right so if you're preparing for interviews as uh As a pre-med right for med school interviews. I can certainly prepare you for that.

I have uh Experience on admission committees So I can certainly certainly certainly prepare you for those purposes and then I can also prepare um Uh medical students if you're applying for residency I can also prepare your application like your iris application. I can help with preparing that uh, I can help with preparing personal statements and preparing for interviews So yeah, those are the things I offer but those are like one-on-one basis Um, I will keep making these podcasts for free. So don't worry about that Um, so I wish all the best have a wonderful Saturday and god bless. I'll see you next time. Thank you

The presence of multiple genes or coding sequences for different proteins on a single transcript.

Monocistronic mRNA (single gene product per transcript).

Pre-mRNA.

sn RNA (small nuclear RNA).

Mature mRNA is the fully processed form, ready for translation; pre-mRNA is the initial, unprocessed transcript.

Polycistronic mRNA.

Polycistronic mRNA.

Monocistronic mRNA.

Splicing.

The fully processed form of the transcript, ready for translation.

Polycistronic mRNA.

Polycistronic mRNA.

Monocistronic mRNA.

Splicing.

The fully processed form of the transcript, ready for translation.