Replication: How does DNA multiply?

By: Bijay Dhungel , MSc

Molecular Biology Series Continued

Cells need to divide continuously by a process called cell division. When new cells are formed from existing cells, the DNA also needs to be multiplied so that the new cells may get their share. DNA replication is a process by which DNA makes copies of itself. After understanding the complementary nature of the two strands in a DNA, it should be straight forward to imagine that each of these strands serve as a template for the synthesis of a new complementary daughter strand. For DNA to replicate, the two strands need to separate. After the separation, each strand functions as a template for the synthesis of a new strand, this happens due to the complementary nature of the bases. A free (unpolymerized) nucleotide recognizes its complementary nucleotide in the template and forms the hydrogen bond, at the same time; it aligns itself for enzyme-catalyzed polymerization into a new DNA chain. The polymerization is carried out by an enzyme called DNA-polymerase which forms the phosphodiester bond between the sugar of the free nucleotide and the phosphate group of the already existing one. DNA replication is an important process which ensures the proper distribution of genetic material into each cell during cell division and also facilitates the formation of numerous copies of a certain gene when required.

 

Mechanism of DNA replication: Each strand of the parent DNA serves as a template for the new strand.

 

 

Semiconservative nature of DNA replication: Each of the daughters of the dividing cells inherit a new combination of DNA double helix i.e. one old and one new strand.