What is the basic unit of a nucleic acid?
Basic unit of a nucleic acid is a nucleotide . The nucleotides are attached in a series to form a polymer called nucleic acid. There are ribonucleic acid and deoxyribonucleic acid.
A nucleotide has three chemical components :
1. pentose sugar which holds base and phosphate:-
2. a nitrogenous base attached to first carbon and
3. a phosphate attached to fifth carbon.
New nucleotide can attach at third carbon of the sugar by forming phosphodiester bond :
RNA is single standed, but in DNA two anti-parallel chains are joined by hydrogen bonds; anti-parallel because orientation of sugar molecule in the twp strands are opposite :