Question

Amino acid is attached to which site of tRNA?

• A. Anticodon loop
• B. 3’ end
• C. 5’ end
• D. D-loop

Answer 1

The Correct Option is B

The amino acid is attached to the 3' end of the tRNA molecule. Transfer RNA (tRNA) is a crucial component for protein synthesis. It functions by matching specific amino acids with their corresponding codons on the messenger RNA (mRNA) during translation. Let's explore the structure of tRNA to understand why the 3' end is the correct site: 

• tRNA Structure: tRNA molecules have a cloverleaf structure, with specific regions known as loops and stems. These include the anticodon loop, D-loop, TψC loop, and the 3' and 5' ends.
• Attachment Site: The 3' end of a tRNA molecule is the amino acid attachment site. It contains a specific sequence, commonly CCA, where the carboxyl group of the amino acid is covalently bonded by the enzyme aminoacyl-tRNA synthetase.
• Function: Once an amino acid is linked to the tRNA's 3' end, the tRNA is considered "charged" and can recognize its corresponding codon on the mRNA through its anticodon loop, facilitating the addition of the amino acid to the growing polypeptide chain.

Thus, the amino acid linkage to the 3’ end of tRNA is essential for accurate translation and protein assembly.

Answer 2

The amino acid is attached to the 3' end of the tRNA molecule. The tRNA has a three-dimensional structure with an anticodon loop that pairs with the mRNA codon during translation, but the amino acid is attached at the 3' end of the tRNA. This attachment is facilitated by an enzyme called aminoacyl-tRNA synthetase.

• The anticodon loop is involved in recognizing the complementary codon on mRNA but is not the site where the amino acid is attached.
• The 5' end is the start of the tRNA, but it does not play a role in amino acid attachment.
• The D-loop is part of the tRNA's structure but does not participate in the attachment of the amino acid.