Question

The general structure of the replication fork and the enzymes and steps involved in resolving Okazaki fragments.

Answer 1

DNA replication starts when helicase unwinds DNA and breaks hydrogen bonds between the two complementary strands of DNA .DNA polymerase can add new nucleotides to the free 3' end of a growing chain synthesis ,one strand grows contionously it is called leading strand synthesized in 5'-3' direction ,there is also the synthesis of lagging strand discontinously,here DNA polymerase adds new deoxyribonucleotides to the free3 ' OH ,in order to provide 3' OH ,RNA primase attaches to the lagging strand of DNA and synthesizes short RNA primer ,then DNA polymerase III add nucleotides to the 3' end of the RNA primer to form okazaki fragment. DNA polymerase -I replaces DNA polymerase-III ,removes RNA and replaces with DNA ,the DNA ligase enzyme joins okazaki fragments to the growing strand, it forms two covalent phosphodiester bonds between the 3' ends of one nucleotide with 5' phosphate end of the other ,ATP is required for the ligase activity .