For 300k views, I'd expect it to be more indepth. But I guess the title is serious- only focusing on leading v lagging strands. For those who have exams coming and are looking for full info: * DNA synthesis uses semi-conservative replication, meaning the newly synthesized (created) strand is made from a parent strand of DNA (the strand that was separated by DNA helicase). * At the start, DNA topoisomerases and DNA helicases (there are many different types of these enzymes, for simplicity I'll just refer to their group name) bind to the target DNA and begin to "unravel" it. DNA helicase binds to a specific place called the Origin of Replication and unwinds it then separates the strands so other proteins and enzymes can fit in and attach. This separation creates the replication fork/bubble mentioned in the video. * An origin of replication is just a specific sequence of nucleotides that acts as an indicator saying "start replication here!" * After the helicases and topoisomerases have opened up the parent strand of DNA- Primase attaches to the origin and synthesizes complimentary RNA bases. This RNA sequence is called a "primer", it is needed because DNA Polymerases can only add to existing DNA strands. * DNA polymerases (there are many types that do different functions) are enzymes that synthesize complimentary DNA strands. These enzymes are made of many subunits that do specific jobs throughout replication, these subunits activate and deactivate throughout replication when they are needed. (You *shouldn't* need to know the individual subunits of each polymerase for a normal exam, however if you do feel free to reply and I can go into a little more depth ^_^) * DNA replication follows a 5' to 3' direction of replication. The 5' and 3' indicate which carbon we are talking about in the sugar molecule (remember: nucleotides are made of sugar, a phosphate group, and a nitrogenous base). The 5' carbon is attached to the phosphate group The 3' carbon is where the the phosphate group of *another* nucleotide will bond- creating a chain of DNA So, the 5' end will always terminate with a phosphate group and the 3' end will always terminate with a sugar molecule. * This is where the actual video begins. However a few important parts are missing. The lagging strand loops around itself so both the leading and lagging strands are pointing the same direction (5'-3')- this allows simultaneous replication of both strands. Also, while replication is happening, the topoisomerases play another important role. It moves ahead of the replication fork/bubble and breaks the bonds between the parent strands, twists the DNA, and then rebinds the two strands. During replication the DNA strands become more and more strained due to (1) the helicases unwinding and (2) the twisting done by the lagging strand. Topoisomerases relieve the tension and prevents DNA from snapping under the pressure. * The polymerases will also "proof-read" the placed bases to make sure every Adenine is bonded to a Thymine and every Guanine is bonded to a Cytosine. This goes on until replication ends (because either a STOP sequence is reached or the parent DNA strand ends). The cell still needs to deal with the RNA primers at the start of the leading strand and scattered throughout the lagging strand. A polymerase (remember: there are many types of DNA Polymerase enzymes) then removes the primers and replaces them with the correct DNA bases. * After all the RNA is replaced with DNA, ligase comes in and anneals the Okazaki fragments together and the two newly replicated strands bond to form a new copy of DNA. That should be enough info for a quick and exhaustive summary to help with any exams! Also, a few notes. (1) I'm only talking about bDNA. (2) I specifically talk about eukaryotic DNA replication. While eukaryotic and prokaryotic DNA replication are both very similar, they have important distinctions such as: * Prokaryotic DNA is circular and only has one origin of replication * Prok. DNA is larger than Euk. DNA (EDIT: my brain broke for a second here- *Euk. DNA is larger than Prok. DNA.* Sorry!) * There are replication proteins and enzymes unique to both eukaryotic and prokaryotic replication. (3) In order for replication to actually begin, there are specific requirements that must be fulfilled such as all dNTP nucleosides being present and the necessary enzymes/proteins, among other criteria. ~ Source: Pre-med student Good luck! =D
+UnderoathLambofgod Thank you for your explanation it changed my outlook. I don't get too how prokaryotic DNA is larger than DNA Eukaryotic. Because Genom of bacteries are less than Eukaryotic (however Euk. have more DNA molecules and every chromosome will not have whole DNA. I'm still not sure if these DNA molecules are bigger than Euk.). I might be wrong Actually im looking for informations about Telomarase and why it makes DNA shorter I still don't get it so i decided to find answer in diffrent language. I hope that someone will dedicate his time and describe this process :) Sorry if i made a misstake because both English and Bio is not my nattive language :D.
+Shifa Zahid oh wow I completely messed that up at the end! I'm sorry for any confusion, eukaryotic DNA is bigger than Prokaryotic DNA. Besides my (embarrassing) little mistake at the end, which individual enzymes would you like to know about? There are many subunits and helper enzymes! :)
+Marcin Gworys Sorry for the awkward reply times, I'm trying to do this between classes and clinicals. I made a mistake and reversed "Euk" and "Prok" somehow- sorry for the confusion! Eukaryotic DNA is definetly larger than Prokaryotic DNA. Anyways Telomerase is an interesting enzyme. Telomerase itself does *not* make the DNA shorter, ligase makes the telomere shorter after replication. Basically- Telomerase makes a series of repeating 6-bp sequences (known as telomeric sequences) at the ends of chromatids. Why do these exist? Because of the lagging strand made during replication! After exonuclease activity by DNA Polymerase, the Okazaki fragments need to be annealed together to make a complimentary strand. But DNA Polymerases must work in 5' --> 3' directionality, that is they need an -OH group to bind to (see bottom of comment). This is where the telomeric sequences come into play! The end of an Okazaki fragment lacks an -OH group so the DNA Polymerase can't *properly* attach to it. Telomeres provide the -OH group that the Polymerase needs, so a primer comes in and attaches to a part of the telomere ahead of the fragment. Now that the DNA Poly. is attached, it can run down the strand and fill in the gaps between the Okazaki fragments at the end. Then the ligase comes in and attaches all the DNA fragments together. The extra telomeric sequences are then cleaved off so just the completed DNA strand is left and can attach to its complimentary strand. So in summary- Telomerase allows DNA Polymerase to bind and "fix" the lagging strand's Okazaki fragments. Telomeres get shorter because they get cleaved off with the replicated strand that used it. Telomerase (the enzyme that synthesizes telomeric sequences) is very active early in our development, but as we age it gets less and less active. Eventually the telomeres get too short to risk transcription (risk the loss of "important" DNA) so replication stops. Important: Eukaryotic and Prokaryotic cells use different DNA Polymerases (prokaryotes uses DNA Poly III and eukaryotes uses DNA Poly I for this specific exonuclease activity). The DNA polymerase in prokaryotic and eukaroytic cells all serve similar functions. However- they usually have noticeably different structures and extra functions that others do not have. But for simplicity's sake- you're usually safe just thinking of them as a one "polymerase" unless you're in a higher-level course. The -OH group binding is important and explained through biochemistry. I'm not a biochem major, so sadly I can't go into great detail about that because I'm not confident in my answer or reasoning for it (I don't want to give you any false information). Sorry :(
Have been trying to understand these two strands for almost a week now, thank you for making it whole lot easier than I thought... this was very helpful...
so all i ever needed to know was when you say DNA is built from 5' to 3' you dont mean the original DNA template but the new strand that is being added it !!!!!!
Great video but you forgot to mention the RNA primers required by the okazaki fragments in order for them to be placed upon the strand. The gaps you are referring to do not appear until those primers are removed, they are then refilled with the proper DNA nucleotides.
Thank you so so much! The confusion about why DNA replication takes place in the 5' to 3' direction and the DNA polymerase moves from 3' to 5' direction was really driving me crazy! This video was super helpful! :)
THANK YOUUUUUH from the bottom of my hearttttttttttt. You are just putting all the scientists aside, and having all the attention ❤️. You are not just explaining by reading lines, which many doctors do. Just explained every single point of the concept, and each second and information you have mentioned was necessary. Thank you. My prayers for you.
I have always wanted an anchor through this whole DNA replication process,never really got a breakthrough until today.Never will I ever struggle again.Thank you very much :)
this video is clear and further cements the concept in my head.(my exams are coming soon). however, from what I remember, there are a few missing points (some are asked in the other comments). 1. DNA polymerase requires a free 3' OH end to add nucleotides to. Therefore, an RNA primer, which is a short sequence of ribonucleotides, (synthesized by RNA primase) is needed to provide a free 3'OH end so that the 5' phosphate end in an incoming deoxyribonucleotide can react with the 3' end to form a phosphodiester bond. 2. phosphodiester bond formation is catalyzed by DNA polymerase. 3. the gaps in the lagging strand are actually occupied by RNA primers. 4. When the lagging strand is completed, DNA polymerase replaces the RNA primers with deoxyribonucleotides (close the gaps) 5. after RNA primers are replaced, DNA ligase is the enzyme that catalyses phosphodiester bond formation between the 3' end of a new Okazaki fragment and the 5' end of the growing lagging strand hope I helped
Very clear and easy to understand. Those complaining, please make a beeline to the nearest library for some voluminous medical pathophysiology text book. Of course details were left out - quite deliberately, and obviously intended in the spirit of "no one left behind."
As soon as you said "it builds in 5' to 3' direction" instead of it replicates 5' to 3' everything made sense. Differentiating between old strands and the new strands being made was where I was confused. Thank you!
thank you soooooo much! the lagging strand being made into Okazaki fragments still confuses me. but you're awesome! glad you took the time to make the video.
I appreciate the video. But, you missed a very important concept ( the reason why i watched this video..anyway) Why are there gaps in the lagging strand if it goes from 5' to 3' direction? whats the difference in that 5' to 3' and the 5' to 3' in leading strand? It has to do with looping of the lagging strand. Which, i still do not understand yet. Gonna look it up more. Just wanted to point it out. Thanks for the video again
Okay. I think I finally understand it and can maybe help you. So basically in the Leading strain the DNA polymerase doesn't have to wait for the new information and can follow the RNA Primer, while in the lagging, the Polymerase and the Primer have to dance over each other.
godetroit91 There are gaps in the lagging strand because everytime the helicase opens the DNA more on the lagging strand, the replication has now to occurs behind the replicated 5-3' segment which is going left to right. a new 5-3 segment which is initiated by the primer starts and later all the primers are replaced by the RNAseH and DNA ligase binds to THEN form one strand like the leading strand. does that make sense? If the process went like leading strand it wouldnt have been a problem but since we go opposite in lagging strand starting from the replication fork(left) down to the 5' end(right) , further opening at the fork by helicase has to be replicated with a new 5-3 end segment.
Thank you for this great video. Please could you tell me if this statement is true: the template strand is READ in the 3-5 direction, and new DNA is MANUFACTURED in the 5-3 direction.
because she didnt tell you anything about the primary fragments in the origins of replication.In the lagging strand primary RNA fragments are built in order to have the elongation.so the leading strand is being built continuously but the lagging strand is being built fragment by fragment between the RNA primars.as you can easily understand there is only one RNA primar in the leading vs many RNA primars in the lagging strand.THUS the one is continuously and the other is not.The video is not the best possible
well, basically when we talk about the direction of the leading template strand then its 3 prime to 5 prime , and lagging template strand is 5 prime to 3 prime. but new strand is always added from 5 prime to 3 prime direction. so its easy and linear in case of leading strand whose direction is opposit to newly sythesized strand. but in case of lagging strand 5-3 , new strand should be added in 5-3 no matter what, so for lagging strand small okazaki fragments are being introduced ( discountinous strand in 5 to 3 direction).
This was super helpful! My only suggestion would be just to practice the lesson a couple of times before the video to lessen the pauses for filler words! But great job!
You're explanation is SO clear. I really needed to understand the Leading and Lagging strand (especially lagging) in order to understand the rest. Everything else, after, is easy bc this has been cleared up! Thanks :)
Definitely cleared up a misconception for me but I do feel that it took a little while to get to the point, maybe you should practice what you are going to say prior so it doesn't take as long to deliver what you are saying, but overall great video.
I fully understand the evolutionary process, but these complex supporting molecular structures for DNA duplication have evolved as separate entities, having no knowledge of the DNA or the correction processes needed.
I had been introduced to this topic today in my AP Biology class and was a little fuzzy about why there was a gap in between the Okazaki Fragments but the explanation given was very helpful, it led to using common sense!
This was very helpful to me, the idea is not to understand the entire DNA replication process but to really get a grasp on lagging vs leading (one concept of many in DNA replication). It's a bit choppy but is worth sticking it out if your struggling with this concept. Once she gets going it makes total sense. Thank you!!!!!!!!
Thank you so much! This really helped. I have watched so many other videos on DNA replication, but none of them went into enough detail regarding the leading and lagging strand like I needed them too, and they didn't break it down like you did. Thank you for this!! You saved my life
I thought this was super helpful, I had worked this sort of logic out in my head after getting myself confused. But was glad to find someone else who thinks through it to make sense the same way I did!! It was perfect :)
My god thank you sooooo so so so much !!!!! These videos have done way more than my textbook, teacher, and notes combined !!!!!! Thank you thank you thanks youuu! It’s the end of the semester and I have to pull 2 A’s out of my butt to pass
I found this very helpful. You actually explained this better than my professor. For those who say they were expecting more detail, the title of this video is "Leading Strand vs Lagging Strand" . The title tells me that it is just meant to help you identify the leading and lagging strands in a DNA molecule. In my own opinion, I think the detail she went into was just right to explain this concept. If you want even more detail, you may want to look for a video that deals more with the entire replication process as opposed to just identifying leading and lagging strands.
A very prominent injustice in higher education is that fact that youtube videos like this are of more educational value than so many salary paid "professional educators". Absolutely disgraceful. I cannot thank you enough!
THANK YOU!!!! :-D Ahh I have had such a mental block trying to figure out leading and lagging strands, and just needed a clear, simple explanation like yours. Thank you so much for your help!! Have a great day!
5' to 3' strand forms a complementary strand that is 3' to 5' - this complementary strand is called the leading strand. Conversely, the 3' to 5' strand forms a complementary 5' to 3' strand called the lagging strand. Remember that DNA polymerase always goes from 3' to 5'
mam,i had a confusion about 5' to 3 ' prime direction.i was trying to know exact mechanism for last 3 hours.finally i viewed your clip.it made me clear.thank u very much.from pakistan
Omggg!!! Thank you so much! I was struggling while trying to understand this whole thing ,but you really helped me out thank you smmm!!! Keep on doing these kind of videos!
I'm so lost since I have a presentation on this topic but I saw this and watched, and I'm like being rescue from drowning 😂😂 it really help me, thank you soo much, this is my answer.. Omg this is the most compliment I can give..☺ Thanks alot
You have NO IDEA how many professors failed to explain this to me and you literally summed it up so well
Professors xidnt failed to explain u failed to understand bruh
😂😂😂😂
For 300k views, I'd expect it to be more indepth. But I guess the title is serious- only focusing on leading v lagging strands. For those who have exams coming and are looking for full info:
* DNA synthesis uses semi-conservative replication, meaning the newly synthesized (created) strand is made from a parent strand of DNA (the strand that was separated by DNA helicase).
* At the start, DNA topoisomerases and DNA helicases (there are many different types of these enzymes, for simplicity I'll just refer to their group name) bind to the target DNA and begin to "unravel" it. DNA helicase binds to a specific place called the Origin of Replication and unwinds it then separates the strands so other proteins and enzymes can fit in and attach. This separation creates the replication fork/bubble mentioned in the video.
* An origin of replication is just a specific sequence of nucleotides that acts as an indicator saying "start replication here!"
* After the helicases and topoisomerases have opened up the parent strand of DNA- Primase attaches to the origin and synthesizes complimentary RNA bases. This RNA sequence is called a "primer", it is needed because DNA Polymerases can only add to existing DNA strands.
* DNA polymerases (there are many types that do different functions) are enzymes that synthesize complimentary DNA strands. These enzymes are made of many subunits that do specific jobs throughout replication, these subunits activate and deactivate throughout replication when they are needed. (You *shouldn't* need to know the individual subunits of each polymerase for a normal exam, however if you do feel free to reply and I can go into a little more depth ^_^)
* DNA replication follows a 5' to 3' direction of replication. The 5' and 3' indicate which carbon we are talking about in the sugar molecule (remember: nucleotides are made of sugar, a phosphate group, and a nitrogenous base).
The 5' carbon is attached to the phosphate group
The 3' carbon is where the the phosphate group of *another* nucleotide will bond- creating a chain of DNA
So, the 5' end will always terminate with a phosphate group and the 3' end will always terminate with a sugar molecule.
* This is where the actual video begins. However a few important parts are missing.
The lagging strand loops around itself so both the leading and lagging strands are pointing the same direction (5'-3')- this allows simultaneous replication of both strands.
Also, while replication is happening, the topoisomerases play another important role. It moves ahead of the replication fork/bubble and breaks the bonds between the parent strands, twists the DNA, and then rebinds the two strands. During replication the DNA strands become more and more strained due to (1) the helicases unwinding and (2) the twisting done by the lagging strand. Topoisomerases relieve the tension and prevents DNA from snapping under the pressure.
* The polymerases will also "proof-read" the placed bases to make sure every Adenine is bonded to a Thymine and every Guanine is bonded to a Cytosine. This goes on until replication ends (because either a STOP sequence is reached or the parent DNA strand ends). The cell still needs to deal with the RNA primers at the start of the leading strand and scattered throughout the lagging strand. A polymerase (remember: there are many types of DNA Polymerase enzymes) then removes the primers and replaces them with the correct DNA bases.
* After all the RNA is replaced with DNA, ligase comes in and anneals the Okazaki fragments together and the two newly replicated strands bond to form a new copy of DNA.
That should be enough info for a quick and exhaustive summary to help with any exams!
Also, a few notes. (1) I'm only talking about bDNA. (2) I specifically talk about eukaryotic DNA replication. While eukaryotic and prokaryotic DNA replication are both very similar, they have important distinctions such as:
* Prokaryotic DNA is circular and only has one origin of replication
* Prok. DNA is larger than Euk. DNA (EDIT: my brain broke for a second here- *Euk. DNA is larger than Prok. DNA.* Sorry!)
* There are replication proteins and enzymes unique to both eukaryotic and prokaryotic replication.
(3) In order for replication to actually begin, there are specific requirements that must be fulfilled such as all dNTP nucleosides being present and the necessary enzymes/proteins, among other criteria.
~ Source: Pre-med student
Good luck! =D
thanks alot... can you tell me a little more?? plus i didn't get how prokaryotic dna is larger than eukaryotic?
plus i wanna know abt individual enzymes..
+UnderoathLambofgod Thank you for your explanation it changed my outlook. I don't get too how prokaryotic DNA is larger than DNA Eukaryotic. Because Genom of bacteries are less than Eukaryotic (however Euk. have more DNA molecules and every chromosome will not have whole DNA. I'm still not sure if these DNA molecules are bigger than Euk.). I might be wrong
Actually im looking for informations about Telomarase and why it makes DNA shorter I still don't get it so i decided to find answer in diffrent language. I hope that someone will dedicate his time and describe this process :)
Sorry if i made a misstake because both English and Bio is not my nattive language :D.
+Shifa Zahid oh wow I completely messed that up at the end! I'm sorry for any confusion, eukaryotic DNA is bigger than Prokaryotic DNA.
Besides my (embarrassing) little mistake at the end, which individual enzymes would you like to know about? There are many subunits and helper enzymes! :)
+Marcin Gworys Sorry for the awkward reply times, I'm trying to do this between classes and clinicals.
I made a mistake and reversed "Euk" and "Prok" somehow- sorry for the confusion! Eukaryotic DNA is definetly larger than Prokaryotic DNA.
Anyways Telomerase is an interesting enzyme. Telomerase itself does *not* make the DNA shorter, ligase makes the telomere shorter after replication.
Basically- Telomerase makes a series of repeating 6-bp sequences (known as telomeric sequences) at the ends of chromatids. Why do these exist? Because of the lagging strand made during replication!
After exonuclease activity by DNA Polymerase, the Okazaki fragments need to be annealed together to make a complimentary strand. But DNA Polymerases must work in 5' --> 3' directionality, that is they need an -OH group to bind to (see bottom of comment). This is where the telomeric sequences come into play!
The end of an Okazaki fragment lacks an -OH group so the DNA Polymerase can't *properly* attach to it. Telomeres provide the -OH group that the Polymerase needs, so a primer comes in and attaches to a part of the telomere ahead of the fragment. Now that the DNA Poly. is attached, it can run down the strand and fill in the gaps between the Okazaki fragments at the end. Then the ligase comes in and attaches all the DNA fragments together. The extra telomeric sequences are then cleaved off so just the completed DNA strand is left and can attach to its complimentary strand.
So in summary- Telomerase allows DNA Polymerase to bind and "fix" the lagging strand's Okazaki fragments. Telomeres get shorter because they get cleaved off with the replicated strand that used it. Telomerase (the enzyme that synthesizes telomeric sequences) is very active early in our development, but as we age it gets less and less active. Eventually the telomeres get too short to risk transcription (risk the loss of "important" DNA) so replication stops.
Important: Eukaryotic and Prokaryotic cells use different DNA Polymerases (prokaryotes uses DNA Poly III and eukaryotes uses DNA Poly I for this specific exonuclease activity). The DNA polymerase in prokaryotic and eukaroytic cells all serve similar functions. However- they usually have noticeably different structures and extra functions that others do not have. But for simplicity's sake- you're usually safe just thinking of them as a one "polymerase" unless you're in a higher-level course.
The -OH group binding is important and explained through biochemistry. I'm not a biochem major, so sadly I can't go into great detail about that because I'm not confident in my answer or reasoning for it (I don't want to give you any false information). Sorry :(
This helped me a lot! Good luck everybody on your exams reading this! Now stop reading comments and go back to your study!!! :)
You got me
will do!
😂😂
2030games lol
lol thanks for reminding me to go back and study
Have been trying to understand these two strands for almost a week now, thank you for making it whole lot easier than I thought... this was very helpful...
I believe it isn't polymerase that fuses the okazaki fragments, but the enzyme ligase.
yes you're correct but DNA polymerase 1 still helps to close the gaps
Yeah
It is DNA polymerase that elongates the okazaki fragments though.
@@trafalgarzoro3441 it was called polymerase I before, but scientists change the word to ligase now
@@terrickhuang7626 Ohh thanks I was still confused.
I'm not stranded anymore. Great video.
>STRANDed
i c wut u did ther
Mood
HA
Chutiya
@@biologyexplorer2721 language
This is the only video that has actually explained clearly the 5' 3' bit! Thankyou so much!!!
so all i ever needed to know was when you say DNA is built from 5' to 3' you dont mean the original DNA template but the new strand that is being added it !!!!!!
indeed ,new nucleotides are added to 3'
DNA polymerase moves from 3 to 5 of DNA template strand
NOBEL ADHIKARI yess 🙌🏼 it becomes much easier when you remember this one point
YES THANK YOU
Hm have u read the book? All books tell u about the new dna not the original.dna, dont blame her lmao, she was right
Good video, but you forgot to talk about primers. Without them DNA Polymerase 3 cannot start replication...
Great video but you forgot to mention the RNA primers required by the okazaki fragments in order for them to be placed upon the strand. The gaps you are referring to do not appear until those primers are removed, they are then refilled with the proper DNA nucleotides.
Arturo Cesar so do the primers on both leading and lagging strand get replaced? By who? Polymerase?
By DNA Polymerase that has a exonuclease activity
Great explanation. I could never understand the 5' to 3' process, but you made it digestible. Thank you!
It was really helpful. I understood the differences between not only leading and lagging strand, but as well as from 5' to 3' confusion. Thank you.
lol that moment when you're like, "OHHHHHH, I get it now!!!!!"
I read this comment before I watched the video and that’s literally what happened to me😂
I had that moment about 3 times throughout the video
frrrrrrrr
Thank you so so much! The confusion about why DNA replication takes place in the 5' to 3' direction and the DNA polymerase moves from 3' to 5' direction was really driving me crazy! This video was super helpful! :)
THANK YOUUUUUH from the bottom of my hearttttttttttt. You are just putting all the scientists aside, and having all the attention ❤️. You are not just explaining by reading lines, which many doctors do. Just explained every single point of the concept, and each second and information you have mentioned was necessary. Thank you. My prayers for you.
I have always wanted an anchor through this whole DNA replication process,never really got a breakthrough until today.Never will I ever struggle again.Thank you very much :)
Really, thank you .. I have studied this during high school and college, there was no teacher or doctor was able to explain it as simple as you did
right
this video is clear and further cements the concept in my head.(my exams are coming soon). however, from what I remember, there are a few missing points (some are asked in the other comments).
1. DNA polymerase requires a free 3' OH end to add nucleotides to. Therefore, an RNA primer, which is a short sequence of ribonucleotides, (synthesized by RNA primase) is needed to provide a free 3'OH end so that the 5' phosphate end in an incoming deoxyribonucleotide can react with the 3' end to form a phosphodiester bond.
2. phosphodiester bond formation is catalyzed by DNA polymerase.
3. the gaps in the lagging strand are actually occupied by RNA primers.
4. When the lagging strand is completed, DNA polymerase replaces the RNA primers with deoxyribonucleotides (close the gaps)
5. after RNA primers are replaced, DNA ligase is the enzyme that catalyses phosphodiester bond formation between the 3' end of a new Okazaki fragment and the 5' end of the growing lagging strand
hope I helped
She said it was for another video dumvass
Omg this 12 yr video summed up everything. Throughout the video I was like, "I got it, I got it." Thank you so much and God bless you
This is the best explanation I've ever come across on this topic
Watch at double speed. You're welcome.
you should do more science videos, because your explanation is very clear and effective
Very clear and easy to understand. Those complaining, please make a beeline to the nearest library for some voluminous medical pathophysiology text book. Of course details were left out - quite deliberately, and obviously intended in the spirit of "no one left behind."
+Joab Magara lol
after 8 years, this video is still being used, God bless you, this really clarified stuff up!
wow this was so much better explained than my professor lol, great video!
yes
This cured my cancer
Oh my goodness, it made so much more sense than possibly any textbook ever written. Thank you so much!
As soon as you said "it builds in 5' to 3' direction" instead of it replicates 5' to 3' everything made sense. Differentiating between old strands and the new strands being made was where I was confused. Thank you!
You are one hell of tutor! BEST DNA replication video ever!
Thank you so much! I was confused about the whole process but i finally understand how this works. Great video!! :D
thank you soooooo much! the lagging strand being made into Okazaki fragments still confuses me. but you're awesome! glad you took the time to make the video.
I've spent couple of hours trying to figure out how DNA synthesis work. Your video made my study easier. Very well explained.
I appreciate the video. But, you missed a very important concept ( the reason why i watched this video..anyway) Why are there gaps in the lagging strand if it goes from 5' to 3' direction? whats the difference in that 5' to 3' and the 5' to 3' in leading strand? It has to do with looping of the lagging strand. Which, i still do not understand yet. Gonna look it up more. Just wanted to point it out.
Thanks for the video again
I was wondering that way too nouman. I wish i could find more tutorial vids on replication. Do you know of any?Please guide. Thanks
Okay. I think I finally understand it and can maybe help you. So basically in the Leading strain the DNA polymerase doesn't have to wait for the new information and can follow the RNA Primer, while in the lagging, the Polymerase and the Primer have to dance over each other.
godetroit91 There are gaps in the lagging strand because everytime the helicase opens the DNA more on the lagging strand, the replication has now to occurs behind the replicated 5-3' segment which is going left to right. a new 5-3 segment which is initiated by the primer starts and later all the primers are replaced by the RNAseH and DNA ligase binds to THEN form one strand like the leading strand. does that make sense? If the process went like leading strand it wouldnt have been a problem but since we go opposite in lagging strand starting from the replication fork(left) down to the 5' end(right) , further opening at the fork by helicase has to be replicated with a new 5-3 end segment.
Mahak Chauhan yeaaah thanks to you i understand now how the lagging strand is working 😚
Thank you for this great video. Please could you tell me if this statement is true: the template strand is READ in the 3-5 direction, and new DNA is MANUFACTURED in the 5-3 direction.
true statement
Remember the mnemonic: Read up, write down.
the only video that has stressed the important of the 5' to 3' I now FINALLY fully understand this operation! Thank you!
This was so much clearer than the book and its figures. THANK YOU !
I still don't understand how it is added discontinuously. I understand all of the directions. But why are there gaps????
because she didnt tell you anything about the primary fragments in the origins of replication.In the lagging strand primary RNA fragments are built in order to have the elongation.so the leading strand is being built continuously but the lagging strand is being built fragment by fragment between the RNA primars.as you can easily understand there is only one RNA primar in the leading vs many RNA primars in the lagging strand.THUS the one is continuously and the other is not.The video is not the best possible
well, basically when we talk about the direction of the leading template strand then its 3 prime to 5 prime , and lagging template strand is 5 prime to 3 prime. but new strand is always added from 5 prime to 3 prime direction. so its easy and linear in case of leading strand whose direction is opposit to newly sythesized strand. but in case of lagging strand 5-3 , new strand should be added in 5-3 no matter what, so for lagging strand small okazaki fragments are being introduced ( discountinous strand in 5 to 3 direction).
Please watch Khan academy videos to clarify that.
This was super helpful! My only suggestion would be just to practice the lesson a couple of times before the video to lessen the pauses for filler words! But great job!
You did great job explaining and I understood you better than some of the other videos. Keep it up the good work.
You have no idea how much this just helped me. Thank you so much!!
explained it better than my prof
Oh god I wish I got a biology professor like you : ( she just keep flashing ppts and shooting in a hypersonic speed while teaching this
Aren't we classmates?! Because my does exactly the same... she must think that we are scientists, and do investigations in our free-time... :/
your explanation for lagging strand, okazaki fragments is very clear! thank you
You're explanation is SO clear. I really needed to understand the Leading and Lagging strand (especially lagging) in order to understand the rest. Everything else, after, is easy bc this has been cleared up! Thanks :)
U know, U r genius!!!!n my life saver!! Tremendous thank U!🌞
Definitely cleared up a misconception for me but I do feel that it took a little while to get to the point, maybe you should practice what you are going to say prior so it doesn't take as long to deliver what you are saying, but overall great video.
u r an angel .... all my doubts regarding lagging strand got cleared after watching this.
Absolutely 100% clear, thanks for making it understandable and the directionality of prime numbers simple to understand.
How the hell did she know I'm having an exam?
very clearly explained
You helped a lot with explaining why there are multiple discontinued strands (Okazaki fragments) made! Thank you!
YOU ARE A LIFE SAVERRRRRRRRR i wenr from not understanding this at all to being able to teach it to others!! And i have an exam tmrw THANKYOU❤️❤️❤️❤️
Thank you so much
Really I did not understand this
But when I watched this video i got it all
Thank you so much again 😍
I fully understand the evolutionary process, but these complex supporting molecular structures for DNA duplication have evolved as separate entities, having no knowledge of the DNA or the correction processes needed.
I had been introduced to this topic today in my AP Biology class and was a little fuzzy about why there was a gap in between the Okazaki Fragments but the explanation given was very helpful, it led to using common sense!
THANK YOU THANK YOU THANK YOU. I was really confused with the Okazaki fragments thing, and now it's way clearer!
HOLY CRAP THIS WAS HELPFUL AS SHIT!!!! THX!!!!!!!!
Helpful for straight up basics but not detail. Do yourself a favor and find a different resource.
Thank you so much! I was so confused and my test is tomorrow. You're a life-saver!
Ur form??
Thank you so much for the clear video!!! I only really came here for the 5' and 3' confusion, but you answered all my questions hahaha👍🏻😃
Man i still don't understand this stuff cause i finished at like 4:30 when she was talking about her helix opening up... sorry...
Sala hutiya
زيييين عنااااااااااانييي هو هو
This was very helpful to me, the idea is not to understand the entire DNA replication process but to really get a grasp on lagging vs leading (one concept of many in DNA replication). It's a bit choppy but is worth sticking it out if your struggling with this concept. Once she gets going it makes total sense. Thank you!!!!!!!!
You taught it better than the head of undergrad research at USF THANK YOU
helix brakers lol
ur my waifu
I was looking for a video specifically on lagging vs leading since I understand all else....I didn't need "in-depth". Thank you very much!! :)
EXCELLENT Job!!!! Thank you for taking the time to make this video. You are a very intelligent young lady!
It was not a good video, my advice would be to plan it before hand and script your words, to many uhms, ahhs, oks, yeahs, etc
Bro stfu
Yeah stahp. It was a good video.
Rajiv PM Why? It was a constructive argument.
lpkzc naw it aint
This girl can't even spell. So that's good advice to script your words
Thanks for this video.....how beautifully you have explained the complex structure in simple words.
you saved my life for my test tomorrow! thanks from India!
u explained it so well that i can totally understand what okazaki fragment is!👍🏼
Thank you so much! This really helped. I have watched so many other videos on DNA replication, but none of them went into enough detail regarding the leading and lagging strand like I needed them too, and they didn't break it down like you did. Thank you for this!! You saved my life
Very helpful video for explaining the leading vs lagging strand. Thank you for sharing this video!
I thought this was super helpful, I had worked this sort of logic out in my head after getting myself confused. But was glad to find someone else who thinks through it to make sense the same way I did!! It was perfect :)
half way through and you're explanations are better than my professor's already
I like the fact you mentioned the basic things which are very important as it helped me understand a lot. Thank you so much
My god thank you sooooo so so so much !!!!! These videos have done way more than my textbook, teacher, and notes combined !!!!!! Thank you thank you thanks youuu! It’s the end of the semester and I have to pull 2 A’s out of my butt to pass
I found this very helpful. You actually explained this better than my professor. For those who say they were expecting more detail, the title of this video is "Leading Strand vs Lagging Strand" . The title tells me that it is just meant to help you identify the leading and lagging strands in a DNA molecule. In my own opinion, I think the detail she went into was just right to explain this concept. If you want even more detail, you may want to look for a video that deals more with the entire replication process as opposed to just identifying leading and lagging strands.
This fully explained what my textbooks didn't.
A very prominent injustice in higher education is that fact that youtube videos like this are of more educational value than so many salary paid "professional educators". Absolutely disgraceful. I cannot thank you enough!
this video is so clearr and amazing... all my doubts are cleared withing 14mins.... nice!!!!!
8 years ago and still helping us i love u ❤😔
THANK YOU!!!! :-D Ahh I have had such a mental block trying to figure out leading and lagging strands, and just needed a clear, simple explanation like yours. Thank you so much for your help!! Have a great day!
5' to 3' strand forms a complementary strand that is 3' to 5' - this complementary strand is called the leading strand. Conversely, the 3' to 5' strand forms a complementary 5' to 3' strand called the lagging strand. Remember that DNA polymerase always goes from 3' to 5'
Short, sweet and to the point. PERFECT. THANK YOU!
mam,i had a confusion about 5' to 3 ' prime direction.i was trying to know exact mechanism for last 3 hours.finally i viewed your clip.it made me clear.thank u very much.from pakistan
Thank you so much seriously. I have a huge test today and my teacher just didn't teach us this well. So glad I found this, nice work! Thanks!
DNA Ligase actually joins the Okazaki fragments. Thanks for the video! It really clarifies the process of replication.
Omggg!!! Thank you so much! I was struggling while trying to understand this whole thing ,but you really helped me out thank you smmm!!! Keep on doing these kind of videos!
best explanation I have seen about the lagging mechanism!!! thank you for making this super simple and easy to understand (finally!!)
Thank you! was getting confused about the leading and lagging strands. you did the basics which made me understand better.
THANK YOU SO MUCH I WAS SO CONFUSED BEFORE AND THIS CLEARED EVERYTHING!!!! THANK YOU SOOOOOOOO MUCH 😊😊😊
I ve been watching a lot of explanations for DNA replication but I understood when I watched this. You are awesome
Thank you thank you. Now all that is left for me is to just study in depth but the overview( which I was struggling to grasp) is clear
I'm now able to understand the difference between Lagging strand and leading strand.
Thank you.😊😊😊
Wow .. Your explanation about lagging strand was awesome
No more questions after watching this video. And this is more confusing me😂
Very nicely teaches. Good work
I'm so lost since I have a presentation on this topic but I saw this and watched, and I'm like being rescue from drowning 😂😂 it really help me, thank you soo much, this is my answer.. Omg this is the most compliment I can give..☺ Thanks alot
You explained this really well! Thank you for taking the time!