Stephen P. Bell (MIT / HHMI) 1a: Chromosomal DNA Replication: The DNA Replication Fork

[@mohammadwahab4263]

Finally something more than BASIC !! thank you!

[@dinornis]

This is absolutely brilliant, thank you so much! I was completely overwhelmed when I first saw the DNALC video elsewhere, and although it was amazing to watch, I wasn't sure how I was going to learn how any of it worked. Watching it again at the end of the video, I could immediately recognise and name the units :)

[@lmtrevino7]

That was really great! Now I know DNA from the very beginning DNA strand, DNA polymerase, Primase, DNA holoenzyme Pol III, DNA Holder, DNA Sliding Clamp, T, synthesize DNA, base pairs, template (toppled into a Primer-Template Junction) (PTJ), helicase, ATP hydrolyzed and the release of junction and clamp occurs.

[@jackyjack9660]

Its so annoying that people get to think they know dna from very beginning by watching a single video on KZbin... Order of reaction and thermodynamic parameters?... ∆G and binding energy?... Enzyme kinetics?... Nothing is explained in all aspects.. So when you say you know the dna from the start you're wrong...

[@patldennis]

@@jackyjack9660 You just gave me douche chills. Why not give her some encouragement for being curious and excited about the topic and tell her there's a lot more interesting tstuff to learn about rather than stifling her enthusiasm?

[@elfullin]

@@patldennis preach

[@prashantkaushik5390]

Thanks for such a clear talk

[@salahudinbholai6622]

Thanks for explaining the various types of dna. Great lesson will rewatch!

[@mxmajewski]

Simply epic, imma show it to everyone at my molecular biology class

[@asishku.pattnayak764]

Po

[@asishku.pattnayak764]

po

[@asishku.pattnayak764]

P

[@asishku.pattnayak764]

P

[@soldieroflife4449]

So how did this evolve? I mean how did the DNA evolve machines that read and replicate it? How is it possible for mutations to come up with such a complicated Intelligent process? Blows my mind.

[@Drifter4ever]

It couldn't evolve. But you are not allowed to say that :-)

[@joshuasukup2488]

Over time traits that increase replication should become more common. Seems like probabilities to me.

[@joshuasukup2488]

Heard initially organisms used RNA for genetic info and enzymes, but then it specialized into DNA (more stable than RNA) for genetic information, and amino chains for enzymes (it is unclear to me why aminoacids became enzymes, but I imagine the choice of 20 bases as opposed to 4 made for more differentiation).

[@BushCampingTools]

So the sliding base clamp here is paramount. Under what natural conditions (if any) does this fail or are we only talking experimental conditions, in order to elucidate the mechansim(s) here?

[@TheRealBrandonGlenn]

I understand that the DNA clamps speed up polymerase activity, is it really necessary for the lagging strang to have a DNA clamp? Okazaki fragments are short and shouldnt really require many bases be added. The way it looks in the presentation is that there is a DNA clamp for each Okazaki fragment, how are they all removed?

[@rtx4094]

this until in the loop when the direction is from 5`-3` the polymerase must synthesis the dna strand thats why we need clamp there too and when the pol reaches to the other primer it falls off

[@geezerdombroadcast]

Think I need some remedial DNA training. Got my Okazaki fragments confused with my polymerases : (

[@DrPiero]

Awesome presentation I really enjoyed watching it as an update on replication and please know I’m a trombone player

[@itamar.j.rachailovich]

Is there a video explaining about DnaA , DnaC and helicase?

[@pramitbanerjee]

its my second favorite professor from MIT! (the first is Erik lander)

[@BushCampingTools]

Sorry my stupid question below, I see if eg ATP transport fails, then no attachment of the sliding clamp, via the loaders , yes?

[@michaelvickers8691]

Sure sounds a lot like a technical lecture involving complex engineering. Imagine trying to design such a complex system then building the various components using bio or synthetic chemistry.

[@KenJackson_US]

One error per 10^10 replicated base pairs is absolutely ASTOUNDING! The whole design is astounding.

[@patldennis]

Yet if there were no errors we'd all be genetic clones. Sharing that status with you gives me cold chills. Perfect polymerases obviously are selected against since none are. and wouldn't a supernatural polymerase have 0 errors?

[@KenJackson_US]

Thank you for reviving my old comment, @@patldennis. It's fun to see that six people agreed with me, probably shortly after I posted it four years ago. It's not clear what point you're trying to make. From prior comments, I assume you're trying to squirm out of the reality of a supernatural creator, regardless of the overwhelming evidence. If that's your aim, you're doing a poor job. We don't know what would have happened had the first couple, in their perfect state, had not sinned. Some theorize that polymerase only became erroneous after that. It seems logical, but there's no data and no way of analyzing it. No experiment is possible, so science must remain mute on that topic.

[@patldennis]

@@KenJackson_US 6 people agreed with you but look at all the similiar comments that got more likes. Too bad you didn't have the balls to be more explicit in terms of supernatural jibber jabber.

[@patldennis]

@@KenJackson_US How does sin affect the function of polymerase?

[@KenJackson_US]

You missed the key points, @@patldennis. I said, _"We don't know ..."_ And also, _"... , but there's no data and no way of analyzing it. ..., so science must remain mute on that topic."_

[@graemelaubach3106]

Wild! Great effing lecture, my man.

[@mamltr]

A very nice talk.

[@peter_smyth]

2:40 "Bumbling mass of mutagenised cells" is a great insult!

[@paulwary]

We need another series of Blackadder.

[@mindyourbussines8698]

Or maybe say cancer lol

[@Zelda456]

Thank you !🙏

[@reinaldolrivera-figueroa7267]

But is this in eukariot?

[@rockapedra1130]

Great video! Thanks!

[@salahudinbholai6622]

Thanks Sara Thornton

[@markoconnell804]

How does the Topoisomerase evolve? If it requires ATP to operate how does it do so during this evolutionary process?

[@patldennis]

Well in light of the fact that there are multiple topoisomerase in any cell; species or taxon it's pretty obvious they evolved based on their sequence relationships- individual topoisomerase types take on more specific functions in derived taxa. If it uses ATP it is probably a member of the ATPase superfamily of proteins which do lots of different things but have an ATP hydrolyzing domain in common with additional domains tacked on over time.

[@rogerscottcathey]

ok, that one error bugs me.

[@alihasandw95]

Poor guy when reading the script lol! The course is amazingly helpful tho. thanks

[@Isaiaswolf66]

What happens with 5' primer ?

[@patldennis]

Ribonuclease H recognizes the specific topology and cuts it out. Short length repair polymerases can then fill that in with DNA.

[@aradhyatripathi7326]

How the ter tus complex replicate DNA ?

[@Thomaaasooo]

it does not replicate DNA, it stops the replisome in procaryotes from replicating more than half (or a little more) of the cccDNA

[@ameliac504]

Helicase runs on leading strand

[@joshuasukup2488]

That is what I was taught as well, maybe this is a newer understanding?...

[@marlenesoifer7219]

Please contact me want to Have more information as assembly , vaccines as much DNA replication as possible thankyou thus far

[@willmcconnell6008]

Out of curiosity what level of education is the demographic watching videos like these?

[@joshuasukup2488]

1 year of technical college general cell biology class

[@saramalik5440]

Do you have notes for this

[@samdoors5132]

Individuals that don’t believe there is a God I hope this kind of knowledge that is passed on to you will change your mind.

[@hashhoomy]

سبحان الخالق العظيم!

[@Drifter4ever]

He's wrong. There's much more DNA in the human body. You could go back and forth to the sun 500 times instead of just once.