Replication

What is meant by replication?

Replication means reproduction i.e., making an exact copy of the parental.

How replication process involved in biological world:

You can see lot of reproduction among organisms, but replication is the term used for reproduction of DNA. This is simply called as DNA replication.

Brief description about the process:

The already existed DNA in cell is considered as parental DNA. This DNA is unwounded into two strands. That two strands acting as a template strands for the upcoming new strands formed.

Tools required to carry out this process:

Tools are nothing but the enzymes. Some notable enzymes and its functions are listed below:

• Helicase:

The parental DNA is in wounded and helical form. Therefore to unwound helical strands, helicase is the enzyme required.

• Topoisomerase:

After the DNA strands start to unwound, half of the DNA strand looks like fork which is called replication fork. The remaining portion of the DNA looks like highly coiled region which is called "super coil". To unwound or to release the supercoil, topoisomerase is required.

• RNA primase:

After the DNA strands unwounded, the process starts with little RNA primers, DNA continue to add on over this RNA primer. To begin this process, RNA primase is the enzyme required.

• DNA polymerase:

After the RNA primer settled on the replication fork. To continue the synthesis of new DNA strands, this enzyme is required. There are two classes of DNA polymerase - one is DNA polymerase (delta) which synthesize DNA in 5' - 3' direction and another one is DNA polymerase (epsilon) which synthesize DNA in 3' - 5' direction.

• DNA Ligase :

During the synthesis of new DNA strands, it looks like broken DNA fragments which is called okazaki fragments. To join these fragments, or to bridge the missing phosphate group, DNA ligase is the enzyme required.

• Exonuclease:

After the DNA got completely synthesized, RNA primers are not needed. To find and remove the RNA primers, exonuclease is the enzyme required.

• Nucleases :

During the synthesis of new DNA strands, some nucleotides may fit in wrong position. To remove this wrong nucleotides, nuclease is the enzyme required.