Which RNA is a major structural and functional component of ribosomes?

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

Answer: (D)

Ribosomal RNA is the major structural and functional component of ribosomes. It forms the core scaffold of the ribosome’s two subunits and houses the catalytic center where peptide bonds are formed, acting as a ribozyme. This RNA-protein complex relies on rRNA to correctly position mRNA and tRNA during translation. Messenger RNA carries the genetic code to be read but does not remain as a structural part of the ribosome. Transfer RNA delivers amino acids and helps match codons to anticodons, but it isn’t part of the ribosome’s core structure. Small nuclear RNA is involved in splicing of pre-mRNA, not in ribosome function. So, the ribosomal RNA is the essential structural and functional element that drives ribosome activity.