RNA Polymerase Role in Transcription — NEET Biology
✅ Asked in NEET 2024An intriguing question is that how is the RNA polymerases able to catalyse all the three steps, which are initiation, elongation and termination. The RNA polymerase is only capable of catalysing the process of elongation. It associates transiently with initiation-factor (σ) and termination-factor (ρ) to initiate and terminate the transcription, respectively. Association with these factors alter the specificity of the RNA polymerase to either initiate or terminate.
RNA polymerase itself can ONLY catalyze elongation (the middle step), not initiation or termination. It needs help from sigma (σ) factor to recognize promoters and start transcription, and from rho (ρ) factor to stop at terminators. Students commonly mistake RNA polymerase as doing all three steps independently—this is wrong. The key is understanding that factors temporarily associate with RNA polymerase to change its specificity. NTA tests this distinction because it's fundamental to transcription regulation and frequently appears in mechanism-based MCQs asking which factor does what.
This paragraph was tested 2 times in NEET.
Given below are two statements: Statement I: In prokaryotes, RNA polymerase is capable of catalysing the process of elongation during transcription. Statement II: RNA polymerase associates transiently with 'Rho' factor to initiate transcription.
Identify the correct statement: (NEET 2021)
Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.