Biomolecules are organic molecules which take part in all the metabolic activities of the living body. Vitamins, lipids, carbohydrates, hormones, proteins and nucleic acids are examples of Biomolecules. Nucleic acids like DNA and RNA are also polymeric forms. There are nitrogenous bases, five-carbon sugar and a phosphate group which bonded with each other to form a DNA or RNA molecule. These Biomolecules involve in the transfer of genetic information from one generation to the next generation in the living organisms.
DNA stands for deoxyribonucleic acid and RNA stands for ribonucleic acid. During the cell division, replica of DNA is formed and passed from one generation to next one. This nucleic acid contains the programmatic instructions which are used in cellular activities. During the production of offspring, these instructions are passed down. Similarly RNA involve in the protein synthesis process. The information for protein synthesis is passed from DNA to RNA which further uses this information for the synthesis of protein molecule. Like other Biomolecules, nucleic acids are also polymers of monomer units. Let’s discuss the structures of monomer units of nucleic acid molecules.
Monomeric nucleic acid consists of three components-a phosphate, a sugar and a base.
These are linked together to form very large polymers as shown below.
The bases are derivatives of two parent aromatic compounds, purine and pyrimidine. Nucleic acid are best known as DNA and RNA.
Like proteins,nucleic acids are informational macromolecules and therefore contain nonidentical monomeric units in a special sequence. The monomeric units of nucleic acid are called nucleotides
- Nucleic acids serve a much broader role in cell activity than simply the storing of genetic information (DNA) or the coding of protein amino acid sequence (RNA).
- Smaller nucleic acids, the monomers serve as the building blocks for the larger polymers of DNA and RNA and also as energy carriers.
- Additionally certain biological compounds serve as co enzymes which consists in part of monomer nucleic acids.
- The most important nucleic acids from the standpoint of damage from toxic chemical agents are the polymers DNA and RNA.
Nucleic Acid Monomer Examples has given Below:-
- Nucleotide are monomers of the nucleic acids DNA and RNA.
- The four nucleotide (nucleic acid monomer) units in DNA are called de-oxyadenylate, de-oxyguanylate, de-oxycytidylate and de-oxythymidylate.
- Thymidylate contains de-oxyribose, the prefix de-oxy is not added because thymine containing nucleotides are not present in RNA.
The most common sites for esterification in nucleotide is the 5th position, for example
the ribo-nucleoside tri-phosphate precursors of RNA are adenosine 5-tri-phosphate (ATP), guanosine 5-tri-phosphate (GTP), cystidine 5-triphosphate (CTP) and uridine 5-tri-phosphate (UTP) and four de-oxy ribo-nucleotides precursors of DNA are de-oxyadenosine 5-triphosphate (d ATP), de-oxyguanosine 5-triphosphate (d GTP), de-oxycystidine 5-triphosphate (d CTP) and thymidine 5-triphosphate (TTP). Unless otherwise, specified the abbreviations AMP, ADP ATP etc represents the 5-nucleotides.