RNA polymerases come in s different forms but share many features a- RNA polymerases performs essentially the same reaction in all cells a- Bacteria have only a single e. RNA polymerases while in eukaryotic cells there are 9 three: RNA Pol I, II and III 1010 RNA polymerases come in different forms, but share many features ◼ RNA polymerases performs essentially the same reaction in all cells ◼ Bacteria have only a single RNA polymerases while in eukaryotic cells there are three: RNA Pol I, II and III RNA polymerase and the transcription cycle