Full form of DNA is Deoxyribo Nucleic Acid. 

Double Helix Structure: DNA has a unique double-helix structure, which resembles a twisted ladder or spiral staircase. The sides of the ladder consist of sugar and phosphate molecules, while the "rungs" of the ladder are made up of pairs of nitrogenous bases.

Nitrogenous Bases: There are four types of nitrogenous bases in DNA: adenine (A), thymine (T), cytosine (C), and guanine (G). These bases pair with each other in a complementary manner: A with T and C with G.