DNA is an abbreviation for deoxyribonucleic acid, but it is usually known by its initials alone. DNA is found in practically all living organisms, and it is now known to carry genetic information from one cell to the next, and from one generation to the next. The units of inheritance, called genes, are actually sections of the DNA molecule. Nuclei of the cells of higher organisms contain thread-like bodies called chromosomes, which consist of DNA, wrapped around proteins.
So understanding how the DNA molecule behaves inside cells helps explain how genetics works at the simplest level.