Which RNA type carries genetic instructions from DNA to the ribosome to build a protein?

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

Answer: (A)

Genetic information is transferred from DNA to the site of protein synthesis through RNA, and the messenger RNA is the one that carries that message. In transcription, DNA is used as a template to synthesize mRNA, which threads the code in codons—triplets of nucleotides that specify the sequence of amino acids. When the mRNA reaches the ribosome, its codons are read, and transfer RNA brings the corresponding amino acids to build the protein, guided by the mRNA sequence. The other RNA types have different roles: ribosomal RNA is part of the ribosome itself, helping catalyze peptide bonds and position tRNA; transfer RNA delivers amino acids to the ribosome; small nuclear RNA participates in processing pre-mRNA in the nucleus. Thus, messenger RNA is the molecule that transmits the genetic instructions from DNA to the ribosome for protein synthesis.