- DNA Replication is a semi conservative process.
- DNA Replication requires a DNA template, a primer (RNA), deoxyribonucleoside triphosphates. Mg+2- ion, DNA unwinding protein a modified RNA polymerase, super helin relating proteins, the products of DNA A, DNA B, DNA C, DNA G, DNA E genes and polynucleotide ligase.
- Replication starts at a specific point called the origin.
- The two strands of the DNA double helir unwind with the help of DNA binding protein, which binds to single DNA strands (SSB protein)
- The unwinding of the strands imposses strain which is relieved by the action of superhelin relaxing protein.
- Initiation of DNA replication requires an RNA primes, which is catalysed by special form of RNA polymerase complimentary to the DNA template close to the origin of replication.
- Deoxyribonucleotides are added to the 3rd end of the primer by the DNA replicating
enzymes i.e, DNA polymerase iii. - DNA polymerase i degrade the RNA primer and catalyses the synthesis of short DNA segment to replace the primer. The segment of DNA is joined to the main DNA by the enzyme DNA ligase.
- Replication takes place discontinuously and short pieces called okazaki fragments are synthesized. One strand synthesize the okazati fragment. Both new strands are synthesized forward and the other backward.
- The okazaki fragments are joined by polynuclotide ligase.
- Replication maybe unidirectional or bidirectional from the point of origin.
Replicon:- The unit of the genome that contains an origin for the initiation of replication and in which DNA is replicated is called replicon.
