Write a note on the chemical composition of nucleic acids.

(N/A) Nucleic acids are biopolymers of nucleotides. $A$ nucleotide consists of a nitrogen-containing heterocyclic base,a sugar,and a phosphate group.
$(i)$ Sugars in nucleic acid:
In $DNA$ molecules,the sugar is $\beta-D-2-deoxyribose$,whereas in $RNA$ it is $\beta-D-ribose$.
$(ii)$ Heterogeneous nitrogenous bases:
The $DNA$ and $RNA$ have two important classes of nitrogenous base residues,i.e.,purine and pyrimidine derivatives.
$(iii)$ Phosphate group:
The phosphate group is attached to the $5'$-carbon of the sugar,which links the nucleotides together to form the polynucleotide chain.