RNA polymerase (RNAP or RNApol), also known as DNA-dependent RNA polymerase, is an enzyme that produces RNA. In cells, RNAP is necessary for constructing RNA chains using DNA genes as templates, a process called transcription. RNA polymerase enzymes are essential to life and are found in all organisms and many viruses. In chemical terms, RNAP is a nucleotidyl transferase that polymerizes ribonucleotides at the 3' end of an RNA transcript.
Read more about RNA Polymerase: History, Control of Transcription, RNA Polymerase Action, RNA Polymerase in Bacteria, RNA Polymerase in Eukaryotes, RNA Polymerase in Archaea, RNA Polymerase in Viruses, RNA Polymerase Purification