Restriction enzymes

[@veronicajulia7897]

guess who has an exam tmrw :)

[@valdrinrama8087]

how was your exam :p

[@trevorphilip6120]

Those who are revising

[@sagnikganguly4651]

I've it today!

[@leahl2321]

I have one in the next hour😥

[@nour.24]

Meeeee

[@Sarah-ev3kp]

Thanks a lot I love this narrator. His voice is very calming

[@C080627]

When making human insuli: Recombinant DNA technology was used.. So they basically extracted the human insulin gene from the source DNA (which is cut by the same restriction enzyme Ecor1). Then, they used the same restriction enzyme Ecor1 to cleave the DNA, these produces the "sticky ends" which will be joined together with the human insulin gene by T4 DNA ligase. After both the insulin gene and the plasmid are joined this is called the "Recombinant DNA". The recombinant DNA is then introduced into the host cells, (usually by heat shock) in this case they used E.coli as the host cells, then the cells take up the plasmid and produced two peptide chains of human insulin, which after being combined, could be purified and used to treat diabetics who at that time were allergic to the commercially available porcine insulin.. Today, Recombinant DNA technology is used to facilitate the production of large amounts of useful low molecular weight compounds and macro-molecules that occur naturally in minuscule quantities...

[@Amaaly7]

"Insulin can be made very cheaply"- and yet exorbitantly priced!

[@deathless3518]

can they invent a time machine so I can go back to 2015?

[@fpypnts]

Came to the comments to say this haha, yeah, $900 vial of insulin. Screw you pharma

[@KenrickLeiba]

only in America, and yet some Americans keep screaming "Communists!" every time universal healthcare is proposed.

[@alisa1727]

@@KenrickLeiba Gotta love to see it in America. I agree, it's ridiculous!

[@dankane4193]

@@KenrickLeiba The moment Drs. become government employees is the moment we have a shortage of Drs. Smart minds will go elsewhere to help people and make money.

[@yan_eng8661]

I love the fact that he says "let's imagine it's called" and then proceeds to give us the actual name. Makes me feel I cane up with the name 😂😂.❤

[@Arora-x8s]

Negawatt

[@ES-nr2hh]

WOW! Thank you for making it so easy to understand..read the article hundred times and still couldn't get it..thanks once again! :)

[@sabinazeynalova1089]

Thanks a lot for accessible and interesting explanation!

[@mouzaa.4638]

Thank you so MUCH! I truly love you

[@D1trox]

Thank you so much!!!, incredible how anyone could explain me this clear before... You have my like and suscription!

[@bangnikabang6501]

you have an amazing way of explaining intricate concepts ! thanks

[@kelvin31272]

What a beautifully explained video from Khan academy

[@hamamathepotato8898]

if the viral bacteria is able to reanneal itself though doesn't the restriction enzymes have to keep coming back to cleave to them after they reanneal?

[@FOFE2004]

that's the most perfect explaining way I have ever seen in my life, Thank you, sir!

[@rosamackenzie2368]

thank you so much - you are the ma of my biological dreams !!!!!

[@anthophile786]

Thnku Khanacademy for this Ur this lecture helps me a lot in my presentation

[@CaptainVelveeta]

great video...it'd be nice if the volume was up a bit...kinda hard to hear on my laptop...thanks :]

[@bluebubbles2735]

Thanks we have to report this and i have no idea so it helps me alot 👏👏

[@fatemehsarmadi8364]

Just a question...are plasmids methylene too? Cleave restrictions enzyme Bakterielle DNA too?

[@nicoletan1418]

This youtube video explained it so much better than the Pearson videos/ my microbio menace of a professor. Thank you for helping me understand !

[@selamtesfaye7423]

Thank you so much for the video. It really helps.

[@duniaalmashi3961]

thank you very much for your explaination

[@ehsansalehabadi1500]

Thank you very much for the informative. If the restriction enzyme only targets external DNA (because you mentioned it has methylated points that recognize its DNA), then how can a bacterial DNA be used to get cut by the restriction enzyme?

[@taracheng345]

This is so amazing! We can utilize bacteria! To make a product that once only our pancreas could make. Thank you Sal and it's good to know it fascinates even you.

[@everythingesmith1452]

thank you! this was very helpul!

[@shirmusic1]

Thanks! One thing I didn't get, how do you cut the bacteria in minute 7:26. Doesn't it have a mathyl group attached to its DNA part?

[@deb000rah]

Did you ever find the answer? That's what I want to know too.

[@bioworld4u]

Thank you so much!😊 It is really helpful.

[@RubaKhaled144]

how do you make the bacterial cell's own restriction enzymes work against it and cut its DNA when originally that was a defense mechanism against viruses and bacteriophages?

[@qwerty-bb3wi]

The bacterial cell has methylase which attaches to its self DNA this prevents the self DNA from being digested by its own restriction enzyme but when the host cell gets infected with another bacteria/virus..then the methylase isn't there to protect their infection causing DNA now the restriction enzyme chops it off.

[@rebeccaraye8762]

@@qwerty-bb3wi but he said that the bacterial dna is taken out of the bacterial cell and exposed to the restriction enzyme which then fragments the bacterial dna producing sticky ends. This is where the insulin gene is then attached to. So why does the restriction enzyme split the bacterial dna if it contains the methylase to protect it?

[@dorsafaya897]

thank you so much, helped me out

[@jenniferpaddack6467]

Very informative. Thank you!

[@simranjoharle4220]

This was very helpful.....tnx a lot.

[@lisen8036]

omg this video helped me soooo much. Thank you!

[@sienablier8931]

Super helpful, thank you!

[@budoor-km7jk]

Thank u so much 🤍🤍🤍🤍

[@nickparker2597]

I thought if the DNA is methylated then restriction enzymes wont touch it. But later in the video the restriction enzyme EcoR1 is used to cleave the bacterial DNA?

[@unknown-mn9wo]

WOW thank you! this was really helpful

[@zpitfiyer]

@khanacademymedicine, what's that word you used for "re-attachement of teh sticky ends?

[@omarHassan-nf2ol]

Thank you so much, it helps alot

[@rowal4252]

Why is the bacterial DNA being cleaved to make sticky ends, I thought only viral DNA was cleaved?

[@nyawirawaithaka4993]

Thank you!

[@bobl9555]

Very helpful, Thanks!

[@mohammedal-hammadi5085]

Very useful video, thank you so much

[@riccardopusceddu6232]

how does methylase recognise the plasmid dna over the viral dna if the virus has already inserted its dna into the bacterial cell ?

[@cathode5115]

Riccardo Pusceddu because the viral dna is not methylated i think

[@habteabghebrehiwot2592]

Great video! thanks

[@varushiweerasinghe5426]

Great explanation!

[@zpitfiyer]

what's the word he used to defined the reattachment of the sticky ends? re-enyl? re-anyl?

[@cozmonauts932]

So many questions, okay the biggest ones are… how did the plasmid DNA get cut? I thought it was protected from the restriction enzymes because of methylation… anyways, did it just happen that the insulin production gene was neatly arranged within two convenient palindromic sequences of DNA at each end for it to be cut out with EcoRI? Or were these sequences inserted there, and if so, how?

[@Jarrod_C]

Ok so when you use Eco R1 to create sticky ends for the insulin gene, how do you know that you didn't damage the sequencing or what will be transcribed for making insulin? How do you prevent the old sticky ends from just reattaching? Meaning how do you make sure the sticky ends of the insulin gene catch on to the bacterial DNA?

[@dharafatnani]

1. He explained it in short. We really have to see promoter, coding and termination sequences in desired gene that is insulin. Also have to attach a marker. 2. It is a matter of chance that the sticky ends of desired gene attach to bacterial (to be more specific plasmid) DNA. Later, we test and isolate those plasmid that uptake our desired gene.

[@ABond008ABond008]

I have a question. If for instance the enzyme broke the DNA to GCTTAA how come insulin gene is CGAATT isn't that too much of a coincidence what about if we want to sequence something else. I am new to this as it is clear so please elaborate. Thank you such a great work you are doing.

[@TheTrueVirus22]

+ABond008ABond008 first of all this is just an example. And second, no it´s not a coincidence because the restriction enzyme is very specific and will always cut at certain places. So if you want to make insulin , you choose a restriction enzyme which opens the DNA at those places, that you want or need.

[@benyahiaamira6830]

I have a question because we aplicate genetic engeneering we choose the restriction enzyme right ? and the RE will cut the DNA and open the plasmid right ?

[@masomehmohammadi1601]

Omg thank you.❤

[@als.6417]

You really helped me learn, thank you!

[@sciencenerd7639]

thanks!

[@nikanamiri4961]

How can we used the restriction enzyme to cut the bacterial DNA if the DNA has the methanol?

[@himals1277]

i understood that DNA is *2 stranded therefore would you have to put an ECoRI on both the top and the bottom strand when you are designing your primers etc.

[@gamearena4259]

Thanks

[@ruhidyusifov2372]

greatest video i have ever watched not because explanation was simple also sorrounded all subject!

[@vladyslavstanynets231]

Nothing specific, didn’t even mention other types of restriction enzymes

[@priyaltripathi1832]

If the sticky ends can easily reanneal, why don't they do so in the case of bacteriophages infecting the bacteria?

[@amonajemi8791]

I was having problem with this when I first read it, the video was comprehensive enough, learned it easily.

[@mohammedaiyaad4546]

Can Coronavirus be eliminated by enzyme or not ?

[@Louis_Cool]

guess who has a presentation tmrw :)

[@hunzilah]

hay sir why does the ECoR need to find this sequence when its suppose to destroy all DNA except the methelsted parts

[@hunzilah]

are the methalaeted parts like the palendromes

[@VibeMD]

Can you please explain Ori (Origin Of Replication) in a Plasmid? Also Antibiotic Resistance and insertional inactivation.

[@sadiafarhan4791]

Please talk on rflp

[@苗青-e7s]

Nice Video may I ask what kind of software you are using to make this presentation? Thanks so much!

[@chiewminglow5268]

can i just say this video explained better than my 2h lecture tqvm

[@joaodecarvalho7012]

I have a question. Why the enzyme makes sticky ends? Certainly is not to help genetic engineers.

[@LaerakDAOC]

lol the 'why?' question here is a lot harder to answer...

[@danger12357]

Sticky ends have overhangs and they are more easily joined together by hydrogen bonds that form between the base pairs in the over hang

[@LaerakDAOC]

Gazi Tasin 'How?' is answerable, but 'why?' is tricky

[@danger12357]

Boss ing Well since hydrogen bonding is easier to break then phosphodiester bond bond, the answer to why is makes sticky ends is because sticky ends attach by hydrogen bonding so during replication the bonds maybe easily broken

[@LaerakDAOC]

Gazi Tasin thats how, but why?

[@pianoguythe1955]

Won't the Ecor1 recoginize that its own DNA is mythaylzed and just ignore it instead of cutting it?

[@duhdahla]

Can i ask...when you remove the bacterial DNA & cut it with the EcoR1, why isn't it methylated? When the bacterial DNA is removed from the bacterium does it lose its methyl groups?

[@sharonowusu1723]

+chelsea newfield the methylation is done by endogenous methylases that methylates certain bases(mostly A and C..i.e. adenine and cytosine residues)..basically, methylation is done to prevent cutting or cleavage by endonucleases at that point.. in the first place if the DNA is removed,it means it was not methylated hence the restriction enzyme was able to cleave it... eg....5'GAATTC3'...3'CTTAAG5'...if for example ,the first A in the first strand is methylated,the restriction enzyme will NOT cleave it. hope it helped!

[@ErinRaciell]

Um this video is not very accurate. The bacterial DNA they are talking about is not technically the actual bacterial DNA but a plasmid that the bacteria acquired due to natural/artificial selection

[@an-es9366]

Excelente!!

[@karmicpower]

Why don't the ends just reattach to each other instead of reattaching to the inserted insulin gene? On a similar note, not clear how exactly restriction enzymes help bacteria to kill viruses, if again, after the enzyme cuts the virus dna, it will reattach?

[@Bruhbruhbro47]

If the viral DNA just reanneals- what is the purpose of the restriction enzyme?

[@peaches5882]

nice explanation

[@user-jz2nx6xt3t]

Very helpful

[@u238willy]

This video needs a bit of help. It's barely correct. It lacks the understanding that the methylation and restriction work together. It lacks the fact that while creating 'sticky ends' in a bacteria, the bacteria doesn't want it to re-anneal, so it would continue to degrade foreign DNA. We've taken RE out of bacteria(s) in order to use them as you've stipulated, but place that in context..

[@angieangie4419]

I think it's a basic idea, not necessarily too in depth. These videos are expected to be watched as you study with a textbook, (which will most likely supply all that info u mentioned above). It's just a quick video to understand the basics of what sticky ends are, and not necessarily how they are affected and treated by bacteria.

[@omaraxmed6573]

How does restruction enzyme cutt the bacterial DNA since it has to protect it from viruses ,because as you said it is methylated !!

[@yokyokriza]

Why are restriction-modification systems important?

[@shobhakotary4477]

thanks for uploading good video

[@owljas509]

Thx

[@furiousgaming604]

My exam is >1hr forward

[@Theguywhoexplores10]

Pagal then why comment. Go and study

[@abdosaeed4328]

thank u sooo muuuchhhh !!!

[@sumedhabanerjee2034]

Can anyone explain whats explained in 4:12

[@karishmasisodiya2052]

Sir can you plzz make video about ( depolymerizing enzyme , organotropism) it's medical microbiology syllabus of m.sc 3 rd sem

[@Batats96Fatma]

wow..finally.. i got it ..thank you ..the molecular biology is always easy with khan academy :)

[@Danishlikeapotato]

What happens after the viral DNA is cut? I assume it also has the ability to amend itself, unless it is removed, how is this done? Also, thank you so much for all your videos, Khanacademy! You've really helped me with my molecular and cellular courses!

[@TheDudeAbides23]

I believe this is done by adjusting temperatures with a thermocycler to choose selectively when the annealing/healing takes place. Also, including tags/fluorescent proteins to see where there was successful recombination is used is how I understand it... I am not sure if I am right but this is what I have experienced.

[@agnulittumc]

How does ecor1 cut at the right place in the human dna to include only the insulin gene? Makes no sense! Ecor1 digestionof human dna is supposed to produce thousands of fragments of different lenghts, some containing the gene for insulin and many more genes. How do we isolate the insulin gene, producong fragments that contain sticky ends?

[@lifelyrics5659]

Is this A level?

[@severerevenge8575]

Very good but not perfect there are many things unclear

[@danielgladish2502]

From 6:19 I understand that Eco R1 targets the palindromic sequence in the bacteria plasmid, but at 6:54 you say that the insulin gene is exposed to Eco R1 and therefore has the sticky ends on either side. Where do the sticky ends come from? Are they added by Eco R1 when the restriction enzyme cleaves the DNA sequence? Or is there the specified palindromic sequence on either side of the Insulin gene in the sequence it has been cut from?

[@kerstenl2028]

whyyy is the volume so low?!

[@azertygduj6170]

الحمد لله استفظت كثير .عدغظا امتحن في نفس الموضوع

[@sohaw8635]

thanks Sir nice video Sir

[@nicholasarnold8028]

Still have no idea what this is for. Why does anyone need this?

[@yahiakhaled253]

This is so confusing dont we use the plasmid for making insulin or are you just saying bacterial dna for simplicity. Btw its a bacterium, not a bacteria. Thank u tho

[@Helen-h7Helen___8a]

What lies ahead? Exclusive interview with Binance's CEO offers insights into future developments

[@romeo7506]

the volume is really so low

[@shahirkhan6344]

Ah! That insulin thing!!

[@Raguji65_HindiTrainer]

super

[@junaidansari3145]

Thank you so much.