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

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

• A. rRNA forms the core of the ribosome and catalyzes peptide bond formation
• B. mRNA carries amino acids
• C. tRNA forms ribosome structure
• D. miRNA regulates gene expression

Answer: (A)

The catalytic center of translation is formed by ribosomal RNA, making RNA the key driver of peptide bond formation. The ribosome’s large RNA component creates the peptidyl transferase center, where the chemical bond between the growing polypeptide (on the tRNA in the P site) and the new amino acid (on the tRNA in the A site) is formed. This RNA-based catalysis means the ribosome is a ribozyme, with the RNA doing the chemistry and the surrounding proteins providing support and structure. In bacteria, this activity is carried out by the large-subunit rRNA (23S rRNA), and in eukaryotes by the large-subunit rRNA (28S rRNA), highlighting that the core catalytic function is RNA-dependent across life. The other molecules have different roles: messenger RNA carries the genetic code to specify which amino acids to add; transfer RNA brings the correct amino acids to the ribosome by matching codons; microRNA regulates gene expression. None of them perform the peptide-bond-forming chemistry at the ribosome’s core.

The catalytic center of translation is formed by ribosomal RNA, making RNA the key driver of peptide bond formation. The ribosome’s large RNA component creates the peptidyl transferase center, where the chemical bond between the growing polypeptide (on the tRNA in the P site) and the new amino acid (on the tRNA in the A site) is formed. This RNA-based catalysis means the ribosome is a ribozyme, with the RNA doing the chemistry and the surrounding proteins providing support and structure. In bacteria, this activity is carried out by the large-subunit rRNA (23S rRNA), and in eukaryotes by the large-subunit rRNA (28S rRNA), highlighting that the core catalytic function is RNA-dependent across life.

The other molecules have different roles: messenger RNA carries the genetic code to specify which amino acids to add; transfer RNA brings the correct amino acids to the ribosome by matching codons; microRNA regulates gene expression. None of them perform the peptide-bond-forming chemistry at the ribosome’s core.