Which molecule functions as the adaptor that carries amino acids to the ribosome during translation?

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

Answer: (C)

In translation, the adaptor that carries amino acids to the ribosome is transfer RNA, or tRNA. Each tRNA molecule is attached to a specific amino acid and features an anticodon that pairs with a complementary codon on the mRNA. This charging of tRNA with its amino acid is done by aminoacyl-tRNA synthetases, which ensure the correct amino acid is attached to the correct tRNA. As the ribosome reads the mRNA, tRNAs deliver their amino acids one by one, and the ribosome catalyzes peptide bonds to link them into a growing protein chain. This adaptor role is what lets the nucleotide sequence in mRNA be translated into a sequence of amino acids.

mRNA, by contrast, carries the coded instructions for the sequence of amino acids but does not shuttle amino acids themselves. rRNA forms part of the ribosome and helps catalyze peptide bond formation. DNA stores the genetic information that is transcribed into mRNA.