Restriction enzymes 

guess who has an exam tmrw :)

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

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...

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

guess who has a presentation tmrw :)

you have an amazing way of explaining intricate concepts ! thanks

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

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?

Thank you so MUCH! I truly love you

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

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

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

What a beautifully explained video from Khan academy

Thanks a lot for accessible and interesting explanation!

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.

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

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?

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 😂😂.❤

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

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?

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

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?

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..

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

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

thank you so much, helped me out

thank you! this was very helpul!

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

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

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

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

thank you very much for your explaination

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?

Very informative. Thank you!

omg this video helped me soooo much. Thank you!

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

Thank you so much!😊 It is really helpful.

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?

Thank you so much, it helps alot

WOW thank you! this was really helpful

Thank you!

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!

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

Very helpful, Thanks!

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?

Very useful video, thank you so much

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

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

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

You really helped me learn, thank you!

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

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

Great explanation!

Super helpful, thank you!

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.

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

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

Great video! thanks

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

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?

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

Thank you so much

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 ?

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

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.

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?

thanks!

Can Coronavirus be eliminated by enzyme or not ?

Why are restriction-modification systems important?

Very good but not perfect there are many things unclear

الحمد لله استفظت كثير .عدغظا امتحن في نفس الموضوع

Thanks

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?

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

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

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

nice explanation

Omg thank you.❤

Very helpful

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

Please talk on rflp

thanks for uploading good video

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

Excelente!!

My exam is >1hr forward

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

thank u sooo muuuchhhh !!!

Thank u so much 🤍🤍🤍🤍

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

whyyy is the volume so low?!

Thx

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

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Can anyone explain whats explained in 4:12

the volume is really so low

Is this A level?

thanks Sir nice video Sir

Doesn't the viral DNA ever get methylated accidentally? Great explanation btw!

Thank you so much.

What can digest an enzyme? A) lipase B) kinase C) proteins D) endonuclease