In genetics, DNA stands for deoxyribonucleic acid. DNA is the hereditary material in all living organisms and many viruses, carrying genetic information crucial for growth, development, and reproduction. Its structure is a double helix composed of nucleotides, which consist of a sugar, a phosphate group, and a nitrogenous base. The sequence of these bases encodes the genetic instructions used in the development of an organism, playing a vital role in both heredity and biological functions.