What is tRNA?

• A. A type of ribonucleic acid that functions as an interpreter in translation. Each tRNA molecule has a specific anticodon, picks up a specific amino acid, and transfers the amino acid to the appropriate codon on mRNA.
• B. The RNA that forms ribosomes.
• C. The linear RNA that encodes genetic information from DNA.
• D. A DNA sequence used to begin transcription.

Answer: (D)

tRNA is the interpreter of the genetic code during protein synthesis. Each tRNA molecule carries a specific amino acid and has an anticodon that pairs with a complementary codon on messenger RNA, ensuring the amino acids are added in the correct order. The tRNA is charged with its amino acid by aminoacyl-tRNA synthetase, and at the ribosome it brings the amino acid to the growing polypeptide chain, matching codons in the mRNA to the growing chain through its anticodon. In the ribosome, tRNA arrivals occur at the A site, the peptide bond forms with the chain in the P site, and the now-empty tRNA exits via the E site. The other descriptions refer to different molecules or functions: rRNA forms the ribosome itself, mRNA carries genetic information from DNA, and a DNA sequence that begins transcription is a promoter.