Which RNA forms the core of ribosomes and catalyzes peptide bond formation?

Which RNA forms the core of ribosomes and catalyzes peptide bond formation?

• A. tRNA (transfer RNA)
• B. rRNA (ribosomal RNA)
• C. mRNA (messenger RNA)
• D. ncRNA (non-coding RNA)

Answer: (B)

The key idea is that the ribosome’s catalytic engine is made of RNA. The large subunit’s ribosomal RNA acts as a ribozyme, forming the active site where peptide bonds are actually catalyzed to link amino acids into a growing protein. This means the RNA component does more than just provide structure; it drives the chemistry of peptide bond formation. Other RNA types have different jobs in the cell—tRNA brings amino acids to the ribosome, mRNA provides the template for the sequence, and noncoding RNAs have various regulatory roles—but none of them serve as the ribosome’s catalytic core. So the RNA responsible for both forming the ribosome’s structure and catalyzing peptide bonds is ribosomal RNA.

The key idea is that the ribosome’s catalytic engine is made of RNA. The large subunit’s ribosomal RNA acts as a ribozyme, forming the active site where peptide bonds are actually catalyzed to link amino acids into a growing protein. This means the RNA component does more than just provide structure; it drives the chemistry of peptide bond formation. Other RNA types have different jobs in the cell—tRNA brings amino acids to the ribosome, mRNA provides the template for the sequence, and noncoding RNAs have various regulatory roles—but none of them serve as the ribosome’s catalytic core. So the RNA responsible for both forming the ribosome’s structure and catalyzing peptide bonds is ribosomal RNA.