Identify the correct sequence of events involved in prokaryotes transcription.
(A) RNA polymerase facilitates opening of DNA
(B) Rho factor of RNA polymerase terminates the transcription
(C) RNA polymerase binds to the promoter
(D) RNA polymerase starts polymerization by using nucleotides triphosphates
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (C), (A), (D), (B)
(C) RNA polymerase binds to the promoter — first. In bacteria, a single RNA polymerase makes all types of RNA. Together with the initiation factor (σ), it binds to the promoter, and transcription starts (initiation).
(A) RNA polymerase facilitates opening of DNA — second. The enzyme opens the DNA helix, so that one strand can act as the template.
(D) RNA polymerase starts polymerization by using nucleotides triphosphates — third. It uses nucleoside triphosphates as substrate and joins them following the rule of complementarity (elongation).
(B) Rho factor of RNA polymerase terminates the transcription — last. When the enzyme reaches the terminator region, the termination factor (ρ) helps it stop. The new RNA and the enzyme fall off the DNA.
NCERT Extract:
Types of RNA and the Process of Transcription – “… RNA polymerase binds to promoter and initiates transcription (Initiation). It uses nucleoside triphosphates as substrate and polymerises in a template depended fashion following the rule of complementarity. It somehow also facilitates opening of the helix and continues elongation. Only a short stretch of RNA remains bound to the enzyme. Once the polymerases reaches the terminator region, the nascent RNA falls off, so also the RNA polymerase. This results in termination of transcription.”