Scale: 10^-8 meters = 10 nm = 10 nanometers

DNA within a Virus

In 1953, James Watson and Francis Crick worked out the structure of DNA. The DNA molecule is composed of two complementary strands in the form of a double helix, like a long spiral ladder. Each strand is made up of a sequence of nucleotides – a substance consisting of a phosphate, a sugar, and a nitrogen-containing base. In all of life, there are but four bases forming the rungs of the ladder of DNA. It is the particular sequence of bases that determines the function of a segment of DNA. See the MoreInfo page for more details on the genetic code.