what is the name of the enzyme that adds new nucleotides to build mrna

The enzyme that adds new nucleotides to build mRNA is called RNA polymerase/06%3A_Module_4-_The_Cellular_Level_of_Organization/6.05%3A_Protein_Synthesis). During transcription, RNA polymerase II catalyzes the formation of a pre-mRNA molecule, which is then processed to form mature mRNA. RNA polymerase adds new nucleotides to a growing strand of RNA, building a strand of mRNA/06%3A_Module_4-_The_Cellular_Level_of_Organization/6.05%3A_Protein_Synthesis).