Ribonucleic acid (RNA) is a nucleic acid composed of a large number of nucleotides (polynucleotide chain). The RNA plays a key role in the conversion of genetic information into proteins. It acts as an information transmitter as mRNA. Special RNA types also perform additional tasks. Even the genome itself consists of ribonucleic acid in RNA viruses. Some of the cell constituents responsible for the conversion of information also contain RNA: mRNA maturation, for example, involves snRNA and snoRNA. The catalytic components of the ribosomes are formed by rRNA and the tRNA transports the building blocks for the proteins. Some special forms of RNA are involved in gene regulation.