Class 12 · Molecular Basis of Inheritance

Bacterial RNA Polymerase and Types — NEET Biology

✅ Asked in NEET 2021
📖 NCERT Source

In bacteria, there are three major types of RNAs: mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA). All three RNAs are needed to synthesise a protein in a cell. The mRNA provides the template, tRNA brings aminoacids and reads the genetic code, and rRNAs play structural and catalytic role during translation. There is single DNA-dependent RNA polymerase that catalyses transcription of all types of RNA in bacteria. RNA polymerase binds to promoter and initiates transcription (Initiation). It uses nucleoside triphosphates as substrate

🖼️Related NCERT figure: Diagram showing the process of transcription in bacteria with three stages: Initiation (showing RNA polymerase with sigma factor binding to promoter on DNA helix), Elongation (showing RNA polymerase moving along DNA with terminator ahead), and Termination (showing RNA polymerase with rho factor releasing the newly formed RNA) (Figure 5.10 Process of Transcription in Bacteria)
NCERT Biology · Class 12 · Chapter 5 · Paragraph 80
How NTA Uses This Concept

NTA tests the fact that bacteria use a single DNA-dependent RNA polymerase to transcribe all three types of RNA (mRNA, tRNA, rRNA), unlike eukaryotes which have three different polymerases. Students commonly mistake this by assuming bacteria also have separate polymerases or that RNA polymerase cannot transcribe all RNA types. Remember: one polymerase in bacteria = all RNA types; different promoters direct which RNA gets made. The enzyme binds to the promoter and uses nucleoside triphosphates as substrate to initiate and continue transcription. This concept is fundamental to understanding prokaryotic gene expression.

Solve This NEET Question

This paragraph was tested 2 times in NEET.

Q1 of 2NEET 2021

The only enzyme in prokaryotic transcription that can catalyze initiation, elongation, and termination: (NEET 2021)

Q2 of 2NEET 2021

Which of the following RNAs is not required for protein synthesis? (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.

88/90
of the NEET 2026 Biology paper matched from the MedicNEET question bank

MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.

88 of 90 NEET 2026 Biology questions traced to MedicNEET10,000+ Biology questionsHindi + English
Free to start · Hindi + English · 10,000+ questions · NEET 2026 pattern
Related Concepts from Molecular Basis of Inheritance
📘Practice all 84 NEET PYQs from Molecular Basis of Inheritance