How is DNA able to replicate?

Answer 1

DNA replication is semi-conservative i.e during replication one strand comes fron the parent and another is made complementary to it .The enzymes which helps in its duplication r collectively called REPLIOSOMES or multiple replication enzyme complex. for replication first unwinding should take place and this is done by breaking hydrogen bonding between the nitrogen bases with the help of HELICASES then SSPBs( single strand binding proteins) keep the strands in structured manner so that easy polymerisation of nucleotides should take place and finally TOPOISOMERASES introduce negative coils in the strand by introducing a nick in one of the strands and rejoins the cut again to remove tension on the strand .But It is actually with the help of DNA polymerases and RNA primer that DNA is able is able to replicate.DNA polymerases r of three types namely

DNA POLYMARASE 1: IT IS INVOLVED IN REMOVAL OF RNA PRIMER IN THE TEMPLATE STRAND OR PARENT STRAND. it should b noted that no DNA polymerase can initiate DNA replication .it is the RNA primer which initiates DNA replication .it start on adding rna which is then removed by DNA polymerase 1 .to initiate DNA replication is not easy for DNA polymerase as they can commit a lot of mistakes n hence rna primer form rna portion only to make a perfect DNA

DNA POLYMERASE2: IT IS TO REPAIR THE DNA DURING INJURY

DNA POLYMERASE3:WHICH IS THE REAL REPLICATING ENZYME

All of them have endonuclease activity in 3'-5' directionwhich help in proof reading or editing function when its frequency of making mistake is 1 out of 10,000 nucleotides.DNA formation has direction always from 5'-3' since the two strands r anti-parralel hence one(LEADING STRAND) is formed in continuous manner while other(LAGGING) in fragments called OKAZAKI FRAGMENTS