# deoxyribonucleic acidZoomA-Z

## Subject - Biochemistry

Fig.1
Section of a DNA double strand

The common abbreviation DNA comes from the English name deoxyribonucleic acid. In German, the abbreviation DNS stems from "Desoxyribonucleinsäure". As the carrier of genetic information in all cells, DNA is of universal importance.

Deoxyribonucleic acids are polymeric phosphodiesters, consisting of two unbranched polynucleotide chains wound around each other into a double strand. The involved nucleotides from the single strands are made of one sugar (deoxyribose), one phosphate group, and one of four nitrogenous bases: (G), (A), cytosine (C), or thymine (T). Within this double helix, the sugar-phosphate units are on the outside and are considered as the "backbone" of the DNA. The two partnering strands are twisted in opposite directions, and are thus designated as antiparallel. This results from the favorable formation of hydrogen bridge bonds between the base pairs A-T (two hydrogen bridges) and G-C (three hydrogen bridges), which produces a complementary arrangement of the single strands within the double strand.

Fig.2

Its assembly from four simple components makes DNA optimally suited for coding genetic information. This information is coded into the sequence of bases (DNA sequence), in which three base pairs (triplet) always code for one amino acid.

Following cell disruption, DNA can easily be isolated through precipitation with acid or alcohol ($NaOAc$/ethanol).