Which enzyme charges tRNA with its amino acid?

Which enzyme charges tRNA with its amino acid?

• A. Aminoacyl-tRNA synthetase
• B. DNA ligase
• C. RNA polymerase
• D. Peptidyl transferase

Answer: (A)

Charging a tRNA with its amino acid is done by aminoacyl-tRNA synthetase. This enzyme is specific for each amino acid and its corresponding tRNA, and it uses ATP to activate the amino acid (forming aminoacyl-AMP) before transferring it to the tRNA’s 3' acceptor end. This prepares the tRNA to deliver the correct amino acid during translation, helping ensure fidelity through possible editing steps that remove mischarged charges. The other enzymes have different roles: DNA ligase seals breaks in the DNA backbone, RNA polymerase synthesizes RNA, and peptidyl transferase catalyzes the peptide bond formation on the ribosome but does not attach amino acids to tRNAs.

Charging a tRNA with its amino acid is done by aminoacyl-tRNA synthetase. This enzyme is specific for each amino acid and its corresponding tRNA, and it uses ATP to activate the amino acid (forming aminoacyl-AMP) before transferring it to the tRNA’s 3' acceptor end. This prepares the tRNA to deliver the correct amino acid during translation, helping ensure fidelity through possible editing steps that remove mischarged charges. The other enzymes have different roles: DNA ligase seals breaks in the DNA backbone, RNA polymerase synthesizes RNA, and peptidyl transferase catalyzes the peptide bond formation on the ribosome but does not attach amino acids to tRNAs.