Which type of RNA forms the major structural component of ribosomes?

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

Answer: (A)

Ribosomes are built from RNA and protein, with the RNA components forming the actual framework and active center. The major structural component is ribosomal RNA, which folds into the shapes that form the two subunits and lines the ribosome’s interior where peptide bonds are formed. In addition to providing structure, rRNA often acts as the catalytic core in protein synthesis, a feature that highlights how RNA can perform enzymatic functions. Proteins contribute stability and help fine-tune the machinery, but they don’t define the core scaffold. The other RNAs do different jobs: tRNA shuttles amino acids to the ribosome, mRNA supplies the template sequence to be translated, and snRNA participates in RNA processing in the nucleus. Thus, ribosomal RNA is the correct choice because it is the principal structural and functional component of the ribosome.