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
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.
This paragraph was tested 2 times in NEET.
The only enzyme in prokaryotic transcription that can catalyze initiation, elongation, and termination: (NEET 2021)
Which of the following RNAs is not required for protein synthesis? (NEET 2021)
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