Final answer:
The bacterial RNA polymerase holoenzyme consists of five subunits: two alpha subunits, one beta, one beta prime, and one sigma subunit, involved in transcription initiation. The correct answer is D. 6; alpha, beta, beta prime, omega, and sigma, acknowledging a typo in the option replacing 'omega' with 'sigma'.
Step-by-step explanation:
The bacterial RNA polymerase holoenzyme is composed of five different types of subunits. These are: two identical α (alpha) subunits, one β (beta) subunit, one β' (beta prime) subunit, and the σ (sigma) subunit, which is involved only in transcription initiation. Therefore, the correct answer is D. 6; alpha, beta, beta prime, omega, and sigma, with the understanding that the 'omega' mentioned in the option is a typo and should be 'sigma.' The core enzyme, without the sigma subunit, is responsible for the polymerization of RNA but lacks specificity in starting transcription at the correct site on DNA. The addition of the sigma subunit forms the holoenzyme, conferring the necessary specificity for correct transcription initiation.