What is mRNA, and what does it do?

• A. Deoxyribonucleic Acid; stores genetic information
• B. Messenger RNA; carries instructions on how to make specific proteins
• C. Ribosomal RNA; forms ribosome
• D. Transfer RNA; matches anticodons

Answer: (B)

mRNA, or messenger RNA, is the transcript that carries genetic instructions from DNA to the protein-making machinery. It’s produced by transcription from a gene, then serves as a temporary template that specifies the sequence of amino acids in a protein by presenting codons—three-nucleotide units—to the ribosome. The ribosome reads these codons and, with the help of transfer RNA delivering the matching amino acids, builds the polypeptide chain. In short, mRNA’s job is to convey the instructions for making specific proteins, not to store DNA information, form the ribosome, or match anticodons directly.