Biology · Molecular Basis of Inheritance · NEET
NCERT says bacteria have three major types of RNA: mRNA (messenger RNA), tRNA (transfer RNA) and rRNA (ribosomal RNA). All three are needed to make a protein. The mRNA gives the template (it carries the copied message from DNA), the tRNA brings amino acids and reads the genetic code, and the rRNA is the structural and catalytic part of the ribosome. For NEET, remember all three take part in translation, so if a question asks 'which RNA is NOT needed for protein synthesis', none of these three is the answer.
tRNA (transfer RNA) brings the amino acids. It is called the adapter molecule because one end reads the codon on mRNA using its anticodon, and the other end carries the correct amino acid. This is why tRNA is sometimes called soluble RNA (sRNA) in older books. In the exam, 'adapter molecule' and 'brings amino acids and reads the code' always point to tRNA.
It is both. rRNA (ribosomal RNA) forms the structure of the ribosome, and in bacteria the 23S rRNA of the large subunit also acts as a ribozyme — it catalyses the formation of the peptide bond. This is a favourite NEET point: rRNA is not just a building block, it is an enzyme made of RNA. This links to the RNA world idea, where RNA acted as both information and catalyst.
Among the choices in NEET, siRNA (small interfering RNA) is NOT required for protein synthesis. Only mRNA, tRNA and rRNA are directly needed to make protein. siRNA works in RNA interference (RNAi) for gene silencing and cellular defence, not in translation. NEET 2021 tested exactly this — the odd one out is siRNA.
Yes. In NEET 2025 the statement 'tRNA and rRNA do not interact with mRNA' was marked INCORRECT. tRNA reads the mRNA codons through its anticodon, and rRNA in the ribosome provides the platform where mRNA is read and peptide bonds form. So both tRNA and rRNA directly interact with mRNA during translation.
Which of the following RNAs is not required for the synthesis of protein?
Which of the following rRNAs acts as structural RNA as well as ribozyme in bacteria?
Statement I: Transfer RNAs and ribosomal RNA do not interact with mRNA. Statement II: RNA interference (RNAi) takes place in all eukaryotic organisms as a method of cellular defence. Choose the most appropriate answer.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Three major types: mRNA (messenger RNA), tRNA (transfer RNA) and rRNA (ribosomal RNA). NCERT states all three are needed to synthesise a protein in the cell.
Because it connects two languages: its anticodon reads the codon on mRNA (nucleic acid language) and its other end carries the matching amino acid (protein language). This adapter idea was postulated by Francis Crick.
mRNA provides the template for protein synthesis. It carries the copied message from the DNA template strand to the ribosome, where the sequence of codons is read to build the polypeptide.
The 23S rRNA in the large subunit of the bacterial ribosome. It catalyses peptide bond formation, so the ribosome's enzyme is made of RNA, not protein.
No. siRNA (small interfering RNA) is a regulatory RNA used in RNA interference for gene silencing. It is not required for protein synthesis, so NEET uses it as the odd one out against mRNA, tRNA and rRNA.
