Deoxyribonucleic acid (DNA) is a nucleic acid found in the cells of all living organisms. It houses the vital genetic directives involved in the growth and functioning of all living organisms; as a result of such behavior, it is considered to be the building block or blueprint of life. DNA is also instrumental in the building of other vital components such as proteins and RNA molecules.

DNA was first classified by the physician Friedrich Miescher in 1869. Several researchers such as Phoebus Levene, William Astbury, and Frederick Griffith further contributed to DNA research and enhanced the understanding of DNA structure and importance in living organisms. James Watson and Francis Crick were the first to correctly identify and state the double-helix model of DNA structure in 1953.

DNA structureWhat Does DNA Stand For

DNA can be found in a range of forms, both in double stranded and single stranded structures. DNA comprises of two lengthy polymers known as nucleotides and they are constructed on sugar and phosphate backbones. The two polymers flow in opposite directions; hence anti-parallel in nature. The backbone consists of four types of molecules connected to them: guanine, cytosine, adenine, and thymine. The order in which these bases are arranged determines the storage of genetic information.

DNA is further arranged in cells as long formations termed as chromosomes. Chromosomes are reproduced prior to cell division via a process known as DNA replication. The DNA chain is typically 2.2 to 2.6 nanometers in width and a single nucleotide unit is 0.33 nanometers in length. DNA comprises of base pairs which join together to form the genetic code, which determines physical characteristics of a living organism. Base pair geometry is determined by the following coordinates:

  • Slide
  • Shift
  • Rise
  • Roll
  • Tilt
  • Twist

The three forms of DNA helix geometries are A-DNA, B-DNA, and Z-DNA.