Which type of RNA forms part of ribosomes?

• A. Ribosomal RNA
• B. Messenger RNA
• C. Transfer RNA
• D. Small Nuclear RNA

Answer: (A)

Ribosomes are built from RNA and proteins, and the RNA component forms the catalytic center and structural framework that actually drives protein synthesis. This ribosomal RNA (rRNA) folds to create the two subunits and acts as a ribozyme, catalyzing the peptide bond formation that links amino acids into a protein. Messenger RNA carries the code for the amino acid sequence to the ribosome, but it is not a part of the ribosome itself. Transfer RNA delivers specific amino acids to the growing chain, but again, it is not part of the ribosome’s core. Small nuclear RNA participates in processing pre-mRNA, not in forming ribosomes. Therefore, the RNA that forms part of ribosomes is ribosomal RNA.