Explain the structure of nucleic acids.

(N/A) nucleoside is formed when a nitrogenous base is attached to the $1^{\prime}$ position of a sugar molecule. In nucleosides,the sugar carbons are numbered as $1^{\prime}, 2^{\prime}, 3^{\prime}$,etc.,to distinguish them from the bases.
When a nucleoside is linked to phosphoric acid at the $5^{\prime}$-position of the sugar moiety,a nucleotide is obtained.
Nucleotides are joined together by phosphodiester linkages between the $5^{\prime}$ and $3^{\prime}$ carbon atoms of the pentose sugar,which results in the formation of a dinucleotide. Further polymerization leads to the formation of a polynucleotide chain,which is the backbone of nucleic acids ($DNA$ and $RNA$).