DNA

Deoxyribonucleic acid, the principal molecule of the genetic apparatus of the cell; consists of a backbone of sugar phosphate esters with side chains of nitrogenous bases Ð the purines and pyrimidines; occurs in the nucleus of most cells as a double strand, twisted together into a helix; one of the strands is the active source of information in the cell, the other serves as a matrix for the formation of the new active strand upon cell division; typically has a size of a 10,000th of a millimeter wide and one millimeter long; each of our cells (generally less than a millimeter long) contains about six feet of DNA