Name: Types of Genetic Mutations
Uploaded: 2019-07-19
Duration: 11 min 34 s
Description: A mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Learn more about mutation and its types.

Question

Explain the process of DNA replication with the help of a schematic diagram.

Accepted Answer

Replication starts at the specific site called the origin of replication or Ori. Following are the events that take place during replication:

At the Ori site, DNA starts unwind and hydrogen bond between the bases are broken down by helicase.

The unwinding of two strands results in the formation of a Y-shaped structure called a replication fork.

Single-stranded DNA binding protein binds to the single-stranded DNA and prevents the formation of secondary structure.

Topoisomerase enzyme releases the tension generated during the DNA unwinding.

The strand whose direction is 3' to 5' towards the replication fork is called the leading strand and its complementary strand is called the lagging strand.

DNA polymerase III need a free 3’ OH end to add new nucleotides, RNA primase enzyme provides a free 3’ OH in the form of an RNA primer.

DNA polymerase starts adding complementary nucleotides to the replicating strand.

The lagging strand is replicated as the DNA gets opened. It has many RNA primers and many short fragments. These short fragments are called Okazaki fragments.

Replication in the leading strand is continuous and in the lagging strand, it is discontinuous.

After completion of DNA replication, the RNA primer is removed by the Endonuclease and the gaps are filled by DNA polymerase I. DNA ligase seals the open ends.

Explain the process of DNA replication with the help of a schematic diagram.

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