Bacterial RNA polymerase characteristics: which statement is correct about the enzymes that transcribe bacterial DNA? Select the best option.

Introduction / Context:
In bacteria, a single type of RNA polymerase transcribes rRNA, tRNA, and mRNA (with different sigma factors for promoter specificity). Its subunit composition and biochemical properties are conserved across many species.

Given Data / Assumptions:

• Core enzyme subunits: typically two alpha (α), one beta (β), one beta prime (β′), and an omega (ω) subunit; sigma (σ) associates for initiation.
• DNA polymerases are distinct enzymes responsible for DNA replication and repair.

Concept / Approach:
The bacterial RNA polymerase is a multisubunit complex (holoenzyme when associated with σ). It is not interchangeable with DNA polymerases, is not glycosylated as a rule, and remains active in vitro (cell-free systems), so not 'only inside the cell.'

Step-by-Step Solution:
Recall subunit architecture of the bacterial RNA polymerase.Eliminate claims about glycosylation and interchangeability with DNA polymerases.Select 'Multisubunit enzymes' as correct.

Verification / Alternative check:
Purified bacterial RNA polymerase performs transcription in vitro, confirming activity outside cells and its multisubunit nature.

Why Other Options Are Wrong:
DNA polymerases and RNA polymerases differ in function and structure. Glycosylation is uncommon for bacterial cytosolic enzymes. 'Only active inside the cell' is false; robust in vitro transcription systems exist.

Common Pitfalls:
Confusing the single bacterial polymerase type with a single polypeptide chain; it is one enzyme type but multimeric.

Final Answer:
Multisubunit enzymes.