DNA Polymerase- definition, structure, types (vs RNA polymerase)


DNA is the molecule that carries the genetic information of living organisms. It consists of two strands of nucleotides that are complementary and antiparallel to each other, forming a double helix structure. Each nucleotide has a nitrogenous base (adenine, thymine, cytosine or guanine), a sugar (deoxyribose) and a phosphate group. The bases on one strand pair with the bases on the other strand through hydrogen bonds, forming the base pairs A-T and C-G.

In order to pass on the genetic information to the next generation of cells, DNA needs to be replicated before cell division. This process involves separating the two strands of DNA and using each strand as a template to synthesize a new complementary strand. The result is two identical copies of DNA, each with one original strand and one new strand.

The enzyme that is responsible for synthesizing the new DNA strands is called DNA polymerase. DNA polymerase belongs to a family of enzymes that can catalyze the formation of new DNA molecules from nucleotides, using an existing DNA or RNA strand as a template. DNA polymerase can only add nucleotides to the 3` end of a growing DNA strand, so it always works in the 5` to 3` direction. It also requires a primer, which is a short RNA or DNA fragment that provides a free 3` hydroxyl group for the first nucleotide addition.

DNA polymerase is essential for life, as it ensures the accurate and faithful replication of DNA. It also plays a role in repairing damaged DNA and preventing mutations. There are different types of DNA polymerase that have different functions and characteristics in different organisms and cellular compartments. Some of them have proofreading abilities that can correct errors during DNA synthesis, while others can bypass lesions or gaps in the template strand.

In this article, we will explore the definition, structure, types and mechanism of DNA polymerase, as well as compare it with RNA polymerase, which is another enzyme that synthesizes RNA from DNA. We will also discuss some of the applications and implications of DNA polymerase in biotechnology and medicine.