The genetic material of most viruses and all cellular organisms, humans included, consists of one or more molecules of deoxyribonucleic acid, better known as DNA. In the nucleus of each human cell, there are 46 chromosomes, and each chromosome contains a single DNA molecule. For comparison, in the bacterial species Escherichia coli, each cell has only one chromosome and thus only one DNA molecule.
Regardless of the organism, every molecule of DNA is constructed of two parallel, ribbons like chains that form a coil, or double helix. …
