6 Steps of DNA Replication

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DNA replication is the process through which a DNA molecule makes a copy of itself. We will explore the enzymes involved in DNA replication, the concept of leading and lagging strands (Okazaki fragments), and walk you through the entire DNA replication step-by-step.
The first step in DNA replication is the separation of the double helix structure of the DNA molecule, which is carried out by DNA helicase. These separated strands serve as template strands in the DNA replication process.
Single stranded binding proteins (SSB) prevents the single template strands from re-annealing, which allows the template DNA strands to stay separated and available for the replication process. RNA primer segments are placed on this unwound DNA by the enzyme primase.
DNA polymerase (III) arrives at the site of the RNA primers to begin replication. The DNA polymerase moves along the template strand, and adds bases that are complimentary to our DNA template strand in an anti-parallel direction: DNA Polymerase reads the template strand in the 3' to 5' direction, but the new DNA strand is produced in the 5' to 3' direction.
Eventually, we differentiate into the leading and lagging strands of DNA. DNA polymerase binds to the leading strand, adding new complementary nucleotide bases to the strand of DNA in the 5’ to 3’ direction as helicase is unwinding the DNA. Chunks of DNA, called Okazaki fragments, are then added to the lagging strand also in the 5’ to 3’ direction. It is important to note that DNA replication always occurs in the 5' to 3' direction!
In the lagging strands, RNAse H (aka DNA Pol I) removes primers as DNA Polymerase (III) approaches. From there, DNA ligase combines the Okazaki fragments. This final step completes the DNA replication process.
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Instructor: Dave Carlson

[@sujufan009]

This is by far the best DNA Replication video I've watched, thank you very much.

[@petersiska7510]

Emphasizing reading from 3 to 5 and writing from 5 to 3 is not effective the explanation is too stretched it could be effectively explained in half of the time

[@andreainzaghi7373]

I agree it is the best becaue it explains WHY and not only WHAT and all of that in ten minutes

[@AsmaaHijazi]

This video literally explained 2 weeks worth of confusion in 17 mins, thank you

[@mayinjaernest334]

hahahahhahha, same here

[@SayWhat336]

Haha 😂

[@Lisa.pizzza]

This is the honestly the only video on DNA Replication that made sense.. you've pretty much included all the important parts without being too fancy.. simple is better!

[@khalidmehsud54]

Good

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Iam from South Waziristan

[@fatimaalkubati6843]

It's 2021 and you are still saving liveesss. This is by far the best video i have seen.

[@rubyrose49]

I just found out that Dave Carlson is battling a brain tumour. I am currently studying for the MCAT and the videos from PremedHQ have been very helpful. Dave is a wonderful instructor. I will be donating to his gofundme as a sign of my utmost appreciation.

[@ownitervi241]

Who's Dave Carlson?

[@rubyrose49]

@@ownitervi241 The person on this video.

[@ownitervi241]

@@rubyrose49 oh, that's sad. Is he doing better?

[@monetweldon2739]

Oh my goodness. How is he?

[@dr.zahraa7665]

Thanks, so much doctor I’ve studied for almost 2 weeks and didn't understand anything till I saw your Channel really appreciate

[@PremedHQ]

Great to hear!

[@briannasthilaire7321]

you're a lifesaver, I was literally struggling until I found this video , you get straight to the point. Thank you!

[@shanksLUL]

Watching this before tommorow's exam.

[@shreepoudel4408]

Better to watch one piece

[@joshemeka2979]

I believe what makes a good teacher is ability to tell your students what they don't know and all they need to know about that, not telling them what YOU know!

[@NicaBells]

This is the simplest, most detailed, yet easiest to understand video I’ve watched about DNA Replication. Thank you so much!

[@nidhikelkar851]

I love how detailed and clear this explanation is. Thank you!

[@emankhalid3948]

Hats off You are genius The best replication video

[@JamesLee-sg2px]

Out of many videos I have watched, he explains things solid and crystal clear!!!!

[@Ido84ba]

I've watched many DNA replication videos, this is by far the most clear, specific and professional one. Thank you!

[@i_am_gods_child]

your videos are so clear and you're so good at explaining! - even though I don't need all the information for the exams I'm doing, I keep coming back to your videos when I don't understand something because they are so good! thanks so much

[@georgejoseph1430]

just wanted to stop by and say that your videos here have helped me massively in my understanding of a variety of mcat subjects. your calm, patient manner of explanation is irreplaceable my friend!

[@kindlykusona4117]

I've been hearing about Okazaki Fragments since middle school and I never truly understood it till now! Thank you!

[@sneha6745]

Sir, I just want to thank you so much for explaining this in such a clear and simple way. I thought I was never going to understand replication. Thank you so much!!

[@Modiferify]

Omg he explained it very well!!!! I Have been looking for a good explanation and I swear i was postponing the exam of molecular genetics a lot .Because the Professor asks the mechanism of Dna replication! I'm so glad i found this explanation. I know nobody is stupid but we sometimes need someone to clarify our ideas and help us understand more. THANK YOU A LOT.

[@maximilianludwig4301]

Thank you Sir. I am not a natural English speaker, that's why I really enjoy your eloquence, the varity of your choice of words. Now all my questions concerning the issue has been answered.

[@mandalorian4620]

Minor correction: First: A-proteins separates the strands initially at AT-rich areas throughout the strand (so replication starts at multiple places simultaneously). (Not a critique, but you forgot them). Second step: SSBs keep the strands from annealing, like you said, while simultaneously helicase unwinds the DNA to further separate the strands. After that Topoisomerase is also important, since it reduce the tension, caused by helicase and thereby prevents supercoiling.

[@jamiek6471]

Hello! I was trying to find some info on A-proteins but could't find any, can you please share a link where it's written about them? i would appreciate it, thank you!

[@melissaatanga4337]

whats AT pls?

[@samanthasonntag6463]

@@melissaatanga4337 Adenine = Thymine rich regions.

[@ahmadfadda2654]

The origin of replication depends on whether the cell is eukaryotic or prokaryotic. In Prokaryotes, the DNA is circular and there is only one origin of replication. What you refer to as A-proteins are the initiator proteins that bind to the origin of replication. In E.coli, the initiator proteins are called DnaA & DnaB. In eukaryotic cells,there are multiple origins of replication on the linear DNA molecule. The initiator protein in eukaryotes is called the origin recognition complex. Source: www.ncbi.nlm.nih.gov/pmc/articles/PMC3783049/

[@melesemengistu1952]

adinosine and thymine@@melissaatanga4337

[@j.y.2858]

Thank you so much! I have watched so many videos about DNA replication and this is the most helpful and clear one!

[@rndmstff516]

I can't even explain how much this video helped me, I have to give a presentation in two days and no other videos/sources led me to understand the whole Primer in 3' and 5' direction thing. Thank you!

[@omarzeid2741]

I wasn’t able to understand replication of DNA until I watched this video. Thank u soooooo muchhhh

[@lucky41210grl]

Clear, concise, and makes perfect sense. I love that you explained popular words that we commonly hear when discussing DNA replication, but may not have fully understood well. We have all heard the term leading strand, lagging strand, semi conservative, etc. but explaining exactly what they mean in conjunction with the full video explanation really increased my understanding.This attention to detail and your clear understanding of the topic really this video apart from all others.

[@jwyryaabdla9284]

In fact, I've watched thousands of videos on KZbin, and this is the coolest and simplest video I've ever found. I really thank you very much it will help me in the final !!!!!

[@jasminerich2151]

This helped me understand DNA Replication better than my teacher has been trying to get us to understand for weeks. THANK YOU!

[@junaidhnediyil9611]

fantastic and the language simply superb

[@opeemboya8042]

I love it too. The tutorial is much easier to understand. English is simple with no deep accent. God bless you sir.

[@beckyklotthor2307]

Such a thorough and well thought-out video. Thank you for the clear, descriptive video!

[@dr.sammasud7401]

Enjoyed the video with good understanding of the process as the professor is soft, clean and clear speaker and covered events of DNA replication in a simplest possible way.

[@appug12]

Amazing.. just discovered your channel hours before a test.. and I am so grateful to you. It cleared a lot of my doubts. Thank you so much. :)

[@dari.kj5]

This is theeeee first video out of about 10 that I completely understand !! You explained this sssssoooo welll!!! omgeee im so glad I found this channel!!

[@mathildabjorkander413]

thank you! have been confused for WEEKS and this video explained everything

[@layla3542]

This was the clearest vid about DNA replication ive seen so far, thank youuu!!!

[@ajangu60]

I am Soo grateful for this! Been thinking a lot about this topic and always encountered problems when studing the lagging strand. Thank You for explaining it soo simply and understandably! The enzyme reads the strand from 3' to 5' but the new one is made from 5' to 3' carbon + since the helicase continues to open up the DNA and the ''lagging'' strand is making DNA in the other direction, it simply needs new primers from time to time to catch up with the replicaton fork!

[@justsimple1212]

This is the best replication video I have ever seen.

[@chynafelix-spady9440]

I have watched so many videos on DNA Replication is this was so helpful!!! its crazy how I can watch 5 videos and not understand and watch yours and totally get it thank you very much!

[@amahlengcobo7967]

Absolutely the best Replication video I have watched!!!...THANK YOU SIR!!!

[@diarlaamaral2580]

Wow! Perfect explanation! This guy deserves it's credit.

[@minaabdulaal5549]

This is the first time I watch a DNA replication video and not get lost!! THANK YOUUU

[@monicaengleson452]

The best video on DNA replication I have seen. Thank you for the instruction. This was a major help reviewing for my Genetics MIDTERM.

[@kassidyp4977]

Thank you so much!! You just don't know how much this has helped me

[@1028wash]

This video helped me on my MCAT and in my Genetics class. Much Thanks!

[@sagharzekri8531]

best video that I've seen about DNA replication

[@shereenbatra3317]

I thought I understood DNA replication but after watching this video, there's so much well-explained info... I have to figure out how to organize it. By far the best channel and video ~

[@saraikwizera6907]

My online teachers never ever explain things like they never told me that replication always starts at 3' and moves towards 5' which is one of the things that confused me so much. They never really explained what a primer was they just told us that it starts the process of replication. Like what?!!!! Teachers like you have made my life so much less complicated

[@NadyaCoolCanal]

Not a premed, I’ve got a bio exam tomorrow and this video honestly helped so much!

[@angellesmith7585]

Thanks for simplifying the process!!! An amazing instructor!!! Thanks for sharing!!!

[@uroosaimtiaz]

Thank you for the wonderful video and the brief, very helpful summary in the description. I will be using it for my open-book exam!

[@redreignss]

I just watched a MIT lecture on DNA replication and yours is 10x better!

[@shannonwright4203]

I finally have a clear understanding of the replication process. Thank you!

[@rainasajid6678]

Clear and to the point explanation! Thank you for your kind work!

[@top10-universalfact18]

it took 7 classes to finish this topic in my university, but you closed 7 classes in class. and i am not going to forget this class. thanks teacher.

[@manabbikashgogoi1551]

So well explained

[@MelsMars25]

He explains this so good, I must say! Def. made it easier for me to explain to someone and for my exam. Thank you so much

[@danishfelipe]

I don't usually comment on videos, but this wonderful. Thank you so much!

[@andreainzaghi7373]

after personal trainer, I took up sport science university and this is the ONLY VIDEO (or almost only) that explains the reason why Okazaki fragments occour!! not only DESCRIBE but also EXPLAIN (the story of the new primers) very well done

[@twishackaul5640]

Thank you so much. This is the best video of DNA replication I have watched so far and the only one which made complete sense. This is a life saver video for me... Thanks!

[@siaweah3440]

I like how u explain things calm and slow.

[@jyothi26rab]

thank you so much ur videos and explanations are much easier to understand than my GAMSAT textbooks readings thanks a lot

[@derarzt4490]

شرح رائع جدا انه افضل شرح شاهدته لهذا الموضوع --احسنت يا دكتور

[@fikkyd]

my gosh this was legit the best video on replication

[@bilienmhasion9411]

He's very clear on explaining about the DNA I like this guy

[@melissaatanga4337]

I think I'm going to cry ,thank you so much for this..

[@splishsplash6708]

You are amazing! Absolutely love your explanations in every vid. Please keep making them.

[@thaisoliveirafigueiredodos7491]

Clear presentation and extremely helpful! Thank you, it was very professional!

[@mafaiiyawi301]

This video is the best explanation of a DNA replication procedure.

[@rachelpama4400]

very clear explanation of the okazaki fragments and how they occur because of the discontinuous replication on the lagging strand. This part is usually missed by students.

[@bingslajoie]

thank you for making this so clear and simple to understand!

[@akka77]

omg you are literally a GOD of biology classes, thank you so much!

[@kpopandme8733]

with your video, i was among the best in my exams. thank you so much DOC.

[@hsupyaethwehtet5961]

Thank you so much,Teacher. I can only memorize because of your teaching style.

[@VeritasEtAequitas]

Excellent teaching. Nice touches like the base work of ligase make this much easier to remember.

[@kyutkami6266]

You were really helpful thank you! The video was direct and simple yet informative.

[@eguagieomozusi2318]

The best DNA replication video so far💯

[@hakeemrouf3654]

Thanks a lot for explaining the process very brilliantly and lucidly..

[@rahuljaiswal8836]

best lecture on dna replication , great , very informative

[@Jere616]

Nicely illustrated and explained. Good job.

[@raghvendrasharma2329]

Thank you for such explanation.Your explanation is great.

[@abeeraismail3980]

It's my exam in the morning and I find that this video proves to be the most effective way to clear the confusion about DNA replication

[@shirokuro73]

I'm a complete layperson, I have no medical education or training whatsoever. I understood this video, at least at the logical level of what each enzyme does, etc. Thank you for a great video!! I started watching videos about SARS-Cov-2 in an attempt to understand more about it, and now I've fallen down a rabbit hole and I think I want to learn a lot more about molecular biology now. I want to learn way, way more about the processes involving DNA, RNA, cells in general - but more than that I'd love to understand how, physically these things work. Ultimately all of this boils down to chemical reactions, right? That's what I'd love to understand. Molecule X bonds with molecule Y due to its shape, structure etc, and BOOM - now you have what's essentially code being executed and - life. Maybe it's my computing science background which is causing me to be so fascinated by this world which until a week or two ago, I knew zilch about (and still do compared to someone who's actually studied it, of course). My mind is kind of blown and I can see me continuing to fall down this rabbit hole. Maybe I'll start looking for actual constructed courses, but for now, videos like this are a great place to start. Thanks again for such a clear, well structured and explained video!

[@ahanaftahmidrifat2986]

thank you very much. few days ago,i've a lot of problem on this topic and i can't think how i can overcome that.but after watching your video i understand many things.so thank you again

[@KashifKhan-sp5he]

Enjoyed learning from u teacher!! As u smiled during delivering the lecture .....so cute of u...nicely delivered 💞

[@stef509]

Loved your explanation! Very easy to follow! Thank you so much!

[@PremedHQ]

Hooray!

[@sarikabist5099]

You explained it very well sir. Thank you for making this topic much easier than before. Waiting for such more videos 🤗

[@relaxingmind5267]

I've never understood this concept but after this video..... Sir Best video ever Great work sir Waiting for more new videos 👍👍 Keep going

[@hannahraye1597]

loving this playlist so far!!

[@mvillada1]

excellent explanation . you make the subject pretty easy to understand thanks a lot for your teaching

[@tess1763]

Incredibly helpful and well explained. Thanks.

[@roseyhuang5096]

OMG! Helped me a lot! Thank you! This is the best DNA replication explanation after all.

[@UC6getkJa5N25K]

파킨슨 이기려고유튜브합니다

[@pineapplecastella2584]

Thank you! Really helpful as this is quite complicated to understand at first. Bless you sir

[@syrenelawan3854]

Thank you!! You saved me a lot of time. Wish my Cytogenetic teacher explained this well.

[@debbycoulthard9295]

Sir, you just make it simpler. Thank u

[@muhammadaliwarraich1968]

Hats off to you! Best video on this topic that I have seen as car as I can remember

[@ceeeedes]

I didn't understand the thing with the leading- and lagging strand. But now I do(At least much better) than i did before, because of this video. Thank you!!

[@hareemzahra1181]

This is the best replication vedio

[@byamukamahamson2294]

It's a quite clear, enjoyable and understandable video, thank you so much

[@beibzamrita5543]

Thanks for making me understand what I couldn't understand for 3 days❤️💯

[@shainajain3030]

Very well explained. By far the best video.

[@aaabbb-xb8fk]

IT IS THE BEST VIDEO EVER ON DNA REPLICATION

[@FUNNYVIDSONLY24]

Best video i have watched so far and understand clearly.