how can 1 easily differentiate nucleic acids i.e guanine from thymine e.t.c

Adenine ,Guanine,Thymine and Cytosine are the nucleotides of human DNA.Nucleotides are of two types:-
1.Purines ;- Double ring structure ex.Adenine & Guanine
2.pyrimidine;-Single ring structure ex. Thymine & Cytosine
These are represented as A for adenine,G for Guanine,T for Thymine and C for Cytosine.In double helix model of DNA one can easily identified these base pairs by this representation as well with pairing pattern and the bonding between these pairs.Adenine pairs with thymine with two hydrogen bonds and Guanine pair with Cytosine with three hydrogen bonds.In RNA Uracil(U) replaces Thymine.
Thanks & regards
Aarti Gupta
askiitians Faculty