The DNA molecule is a hereditary material transmitted from generation to generation. It is the largest molecule of the living cell composed of several million nucleotide chains. It is in the sequence of nucleotides in polymers that genetic information carried by chromosomes is found.
Each nucleotide is composed of three parts: nitrogenous base like purine and the pyrimidine , a sugar ( deoxyribose ) and a phosphate group. The nitrogen base determines the identity of the nucleotide.
RNA is a nucleic acid having a structure almost similar to that of the DNA molecule except one base of uracil instead of thymine. There are three different species of RNA. All these elements are essential in the normal functioning of the cell, especially in the synthesis of proteins. The RNA molecule is not the information carrier with the exception of a few viruses. In addition, these molecules are less stable with respect to the DNA molecule. Further explanations about their structure and functions are given in the following pages.
Deoxyribonucleic acid (DNA):
Watson and Crick, in 1953, discovered the three-dimensional model of the DNA molecule and postulated that it consisted of two helical strands wrapped around the same axis forming a helical double-helical structure. The hydrophilic skeleton groups of deoxyribose and phosphate alternate is located outside the double helix opposite the surrounding aqueous media. The purine bases and pyrimidine both strands are stacked inside the double helix, their hydrophobic bases forming almost planar annular structures very close to each other and perpendicular to the long axis of the DNA.
Deoxyribonucleic acid (DNA) is a macromolecular molecule complex structurally and functionally present in various organisms. It is much more abundant in eukaryotes than in prokaryotes. Therefore, it must have certain properties (ie super winding) through which it can be conveniently housed in the cell. It is composed of four different types of building blocks called nucleotides.
Ribonucleic acid (RNA):
RNA is one of two nucleic acids found in organisms such as animals, plants, viruses and bacteria. These are non-genetic documents and they simply translate coded messages .
RNA molecule a uracil (not stable) as one of its bases unlike the DNA molecule that has the base of Thymine. Thus, RNA can easily bend resulting in the formation of secondary structures. When he gets layer , uracil binds to Adenine, which stabilizes the secondary structure.
Ribose sugar in RNA has a maximum number of OH groups on its carbon atoms relative to the DNA molecule. This maximum number of OH groups in RNA assists in the realization of other cellular processes.
DNA and RNA are very important constituents in the living cell. DNA is the usual genetic material of most organisms while RNA is the genetic material of some viruses.
Most of the DNA is in the chromosomes. They are also present in the cytoplasm as in mitochondria and chloroplasts.
Basically, they differ in their chemical structure. Methyl-protected thymine DNA gives extra stability while RNA has uracil without any protective group. Thus, DNA is most suitable as the hereditary material as the RNA molecule.
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