THE ROLE OF DNA IN STORAGE, EXPRESSION AND TRANSMISSION OF
GENETIC INFORMATION
Genes carry the heredity information from one generation to the next in a form of
Deoxyribonucleic acid (DNA).DNA is the key molecule that is responsible for the storage,
expression and transmission of genetic information. DNA is a long double stranded polymer and
it packaged perfectly so, that it can be compacted and stored in the nucleus. DNA is stored by
tightly winding itself around histones forming a nucleosomes, nucleosomes coil themselves up
to form a chromosomethat we know .This packaging allows large amount of genetic information
to be stored in the nucleus.The various combination of bases (Guanine, Adenine, Cytosin and
Thymine) are grouped into gene and each gene provides a blueprint for a specific protein. Each
and every one of us have two copies of genes from our parents
The structure of the DNA makes it possible to store genetic information because DNA is made
up of 2 long unsaturated complementary antiparallel polymers that make a helical shape when
twisted and has three different nucleotide in the strands. The nucleotides consist of a five carbon
sugar (deoxyribose), phosphate group and nitrogenous bases and they are bonded covalently so
,that they maintain stability in the structure of the DNA ,the backbone which is made up of a
phosphate group and sugar form a covalent phosphodiester bond, sugar and nitrogenous base
form covalent glycosidic bond. The nitrogenous bases are divided into purines that has a double
ring (Adenine and Guanine ) and pyrimidines that has a single ring ( Thymine, Cytosine and in
RNA Uracil) this bases form complementary pairs and are held together by hydrogen bonds,
Thymine and Adenine having two hydrogen bonds while Guanine and Cytosine has three of this
bonds.
DNA is synthesizes through the process of replication which enables DNA to express the genetic
code embedded in it. The replication of DNA begins at a particular site called the origins of
replication which is short stretches of DNA having a specific sequence of nucleotides that are
recognized by proteins that initiate DNA replication separating the two strands opening up a
bubble. The DNA helicase unwinds and separates the two parental strands to make new daughter
strands, topoisomerase breaks, swivels and rejoins the parental DNA ahead of the replication
fork, relieving the strain caused by unwinding. Molecules of single-strand binding protein
stabilize the unwound parent strands. Primase synthesizes RNA primers, using the parental DNA
