Ribonucleic acid

(RNA); a macromolecule consisting of ribonucleoside residues connected by phosphate bonds, concerned in the control of cellular chemical process, especially protein synthesis

Description
RNA is found in all cells, in both nuclei and cytoplasm, and also in many viruses. It is transcribed from DNA using complementary basepairing (DNA:RNA - A:U, C:G, G:C, T:A), regulated by the gene structure (the RNA-coding DNA elements and associated control elements) and associated control molecules, including proteinaceous transcription factors. Besides coding for proteins as messenger RNAs, templates for the processing of other RNAs as snRNAs, siRNA and stRNAs, RNAs can also function as enzymes (elements catalysing chemical reactions) in their own right, as so-called ribozymes. Their versatility has spawned the hypothesis that all live might have started and evolved from an initial, solely RNA-based stage of development.