What sequence is typically found at the 3' end of a tRNA molecule?

What sequence is typically found at the 3' end of a tRNA molecule?

• A. GUA
• B. CAG
• C. CCA
• D. UGA

Answer: (C)

A key feature of functional tRNA molecules is the CCA sequence at their 3' end, which provides the attachment site for the amino acid. In maturation, many tRNA genes are completed by adding this CCA tail after transcription, and the amino acid is linked to the terminal adenosine of that tail by aminoacyl-tRNA synthetase. This setup is what makes translation possible, as the amino acid is delivered to the growing polypeptide chain from this end of the tRNA. So the typical 3' end is CCA, which is why that choice is the correct one. The other short sequences don’t serve as the universal 3' terminus and don’t provide the aminoacylation site.

A key feature of functional tRNA molecules is the CCA sequence at their 3' end, which provides the attachment site for the amino acid. In maturation, many tRNA genes are completed by adding this CCA tail after transcription, and the amino acid is linked to the terminal adenosine of that tail by aminoacyl-tRNA synthetase. This setup is what makes translation possible, as the amino acid is delivered to the growing polypeptide chain from this end of the tRNA. So the typical 3' end is CCA, which is why that choice is the correct one. The other short sequences don’t serve as the universal 3' terminus and don’t provide the aminoacylation site.