RNA

Ribonucleic acid; large chain-like molecules, composed of four different building blocks (nucleotides).

The connection of nucleotides is resulting in a molecular backbone of repetitive, identical units (alternating phosphate and carbohydrate groups; the respective phosphorus atoms are marked in yellow, the oxygen atoms are marked in red). The biological information of RNA is coded as the sequence of the four different side chains of nucleotides, extending away from the backbone. (These so-called bases are marked in blue colour, due the nitrogen atoms they are containing.) In a cell, RNA molecules are constructed according to the template of a DNA molecule with a corresponding sequence of side chains.

There are only a few chemical differences between DNA and RNA molecules regarding the carbohydrate group and one side chain. Due to these differences, DNA molecules are especially suitable as a long term storage form of biological information. RNA molecules, in contrast, are less stable but easier to adapt to various functions (mRNA, tRNA, rRNA).