Which RNA forms the structural and catalytic core of ribosomes?

Which RNA forms the structural and catalytic core of ribosomes?

• A. Codon
• B. tRNA
• C. rRNA
• D. mRNA

Answer: (C)

Ribosomes rely on RNA for their core function. The RNA components of the ribosome actually carry out the chemistry of translation. In the large subunit, the rRNA forms the peptidyl transferase center, the site where peptide bonds are formed between amino acids — this is what makes the ribosome a ribozyme. In bacteria, this catalytic activity comes from the 23S rRNA (and in eukaryotes from the corresponding 28S rRNA). Proteins around the RNA provide structural support and help with assembly, but they do not carry out the chemical synthesis themselves. tRNA acts as the adaptor that brings amino acids to the ribosome and recognizes codons on mRNA through anticodons, while mRNA provides the template sequence. A codon is simply a triplet of nucleotides on mRNA, not a catalytic component. Because the catalytic core and the structural framework are formed by rRNA, it is the RNA that forms the heart of the ribosome’s function.

Ribosomes rely on RNA for their core function. The RNA components of the ribosome actually carry out the chemistry of translation. In the large subunit, the rRNA forms the peptidyl transferase center, the site where peptide bonds are formed between amino acids — this is what makes the ribosome a ribozyme. In bacteria, this catalytic activity comes from the 23S rRNA (and in eukaryotes from the corresponding 28S rRNA). Proteins around the RNA provide structural support and help with assembly, but they do not carry out the chemical synthesis themselves.

tRNA acts as the adaptor that brings amino acids to the ribosome and recognizes codons on mRNA through anticodons, while mRNA provides the template sequence. A codon is simply a triplet of nucleotides on mRNA, not a catalytic component. Because the catalytic core and the structural framework are formed by rRNA, it is the RNA that forms the heart of the ribosome’s function.