• Nucleic acids are a long chain polymers of nucleotides which are joined
together by means of phosphodiester linkages.
Two types- DNA & RNA
Nucleiotide of DNA and RNA are made up of – Nitrogenous base, sugar and
phosphate.
• In phosphodiester bonds, one phosphoric acid molecule forms bonds with the
3′ carbon of one pentose molecule as well as with the 5′ carbon of a second
pentose molecule.
• Thus each sugar and phosphoric acid forms bonds with two phosphoric acid
and pentose molecules; these linkages generate the sugar-phosphate
backbone of the nucleic acids. The DNA and RNA bases are attached to the 1′
carbon of the pentose residues.
• This assembly of phosphoric acid, pentose and organic base residues is known
as polydeoxyribonucleotide in case of DNA and polyribonucleotide in case of
RNA. Each nucleotide is composed of three distinct molecules : one molecule
each of sugar, phosphoric acid and a nitrogenous base.