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I understand...nucleotide is made out of a nucleobase, a phosphate, and a sugar... my question is how these sugar,base and phosphate helps DNA molecule in replication ?and maintenance...
What do they do...I mean
in DNA replication
Well, in DNA replication, nucleotides are strung together directly.
The fourth category of biological macromolecules is nucleic acids, which carry the genetic information needed to build organisms. There are two major types of nucleic acids: deoxyribonucleic acids (DNA) and ribonucleic acids (RNA).
The nucleotides are the building blocks of the DNA molecules.
Everyone is allowed to give his/her answers! about my question..May be I couldn't ask it that way I wanted to ask..So you people give your answers..I'll try myself to understand then..
In a cell, DNA replication begins at specific locations, or origins of replication, in the genome.Unwinding of DNA at the origin and synthesis of new strands results in replication forks growing bidirectionally from the origin. A number of proteins are associated with the replication fork which assist in the initiation and continuation of DNA synthesis. Most prominently, DNA polymerase synthesizes the new DNA by adding complementary nucleotides to the template strand.
check this out Ryann http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter14/how_nucleotides_are_added_in_dna_replication.html
Correct me where I'm WRONG.. Replication , DNA and Nucleotides: The weak hydrogen bond that hold together the double helix of DNA is spoken up by enzyme endonuclease starting from the end like a zip, one by one each purine then separates from its pyrimidine partner. Each separation leaves an unmatched purine and pyrimidines bases.Then nucleotides which are present in cellular pool could pair with exposed bases on both unwound strands. Each parent strand remains infact and a new companion strand is assembled on each one. Now during the replication, each parent strand is twisted into a double helix with its new partner strand.Through these steps, a new upright of sugar and phosphate would be supplied for each ladder..so each strand will have replaced the nucleotides partners it has lost with new ones of exactly the same kind.
Energy and enzyme for replication: The DNA helix doesn't unwind itself, Batteries of enzymes and proteins unwind it and keep the two strands separated.DNA polemerases catalyses the assembly of short nucleotide segments and parent strand.Those enzyme also (poor read) the growing DNA double helics for mismatched base pairs which are with correct bases.This is the reason that DNA is replicated ..
General, but fine... You forget a little funny thing: the DNA polymerase ALWAYS synthesis in the 5' to 3' direction, leaving the question: What do we do with the lagging stand? (3' to 5') The answer is Okazaki fragments. In additon to that helicase and topoisomerase are some good enzymes to know as they are making sure the DNA is being unfolded correctly. Also the enzyme DNA ligase is good to know as it is the enzyme that contain the function of binding DNA fragments together. And one last thing: We do not know any DNA polymerases that are capable of synthesizing a string by it self, it need a form of template we call "a primer". The primer is some RNA that is being bound to the DNA by primase, from where the DNA polymerase can begin it's polymerization. RNA primers are removed by DNA polymerase and the enzyme ligase seals the sugar-phosphate backbone. But in general you are on the right track, and I think going into the very protein complexes in the initiation of replication is to much.
that is broken up* above I mistakenly wrote spoken up :P Thanks for detail..and help :)@Frostbite
Hehe but the 5' to 3' problem can make people a little confused.. the way I got over it was just to look at it until I said "OOHHHH now i see it!!!"
If I go in more detail I'll surely get confused..xD So This much Information is enough at this level ..
Right but just try look at the figure, look up some of the words if in doubt. I think that figure is so damn great! very simple and explain a lot.
Yes..I'm trying to understand that figure..c:
It takes some time for me...But I'll understand it Surely ..:)
It does. else try go on youtube and find some animations. :)
That site given by @amtal is also helpful...There is an animation that is describing it well..
oh thanks Ryaan :P
A long conversation. :P
Its about DNA +replication+nucleotides where I was stuck:P @Falco276
"The weak hydrogen bond that hold together the double helix of DNA is [broken] up by enzyme endonuclease" endonucleases break phosphodiester bonds not hydrogen bonds, so they separate nucleotides on the same strand not across. nucleotides themselves don't "help" in the replication process, just as if you're writing a sentence, they are just letters put together by the machinery (enzymes). A feature of stability that nucleic bases do have, though, is that they're aromatic. During replication, polymerase (I) is powered by the lysis of phosphoanhydride bonds and has a the ability to proof-read as it adds nucleotides along a chain, by backing up and cleaving the mismatch off (5' -> 3' direction allows this, if it was the other way, no mismatch repair could occur because there would be no bonds to fuel this reaction). SO that's a way to maintain the strands intact. Although errors do occur. As Frostbite mentioned, there are a lot of proteins that are involved in replication from the unwinding, priming of strands, re-attaching polymerase when it "slips off" the strand, attaching nucleotides on the same strand, etc. It's important to know what all of these do, watching videos on youtube IS helpful but they usually don't go into as much detail as a book. (I like Molecular Biology of the Cell by Johnson, you can find it for free online). You should glance over this file
Little confusion....What is the difference between hydrogen bonds and phosphodiester bonds? :I
phosphodiester bond exists between the phosphate of one nucleotide and Hydrogen bonds join the the nitrogenous bases and hold the two strands together
Phosphodiester ALREADY? exist b/w nucleotide? While Hydrogen bonds joins the nitrogenous bases? is it?
watch these videos , ryaan . 1.http://www.youtube.com/watch?v=teV62zrm2P0 2.http://www.youtube.com/watch?v=-mtLXpgjHL0 3.http://www.youtube.com/watch?v=oNW_ykH3AvA 4.http://www.dnalc.org/resources/3d/04-mechanism-of-replication-advanced.html and for more , go to http://en.wikipedia.org/wiki/DNA_replication
for more confusion.:(
forgt everything.download and watch those videos.they will help you :)
Alright..Thanks everyone for helping me.
@aaronq "University of Toronto" the doc say in the bottom. A doc you have been working with your self?
@Ryaan : go stdy kitty