RNA Polymerase in prokaryotes

Transcription in prokaryotes is simpler but very similar to that in eukaryotes. Transcription requires RNA polymerase. RNA polymerase structure contains two alpha and beta subunits. Sigma factor is needed to direct the polymerase to the TATA box. RNA polymerase in its closed form is inactive. Transcription factors attaches to the complex and opens the polymerase to an active form.