In the process of protein synthesis the amino acids bind to tRNA at:

The correct answer is Option (2) → 3' end

The amino acid binds to the amino acid acceptor end of tRNA, which is its 3′ end (ending in CCA).

Option (1) Anticodon site — Incorrect. The anticodon pairs with the codon on mRNA; it does not hold the amino acid.

Option (2) 3' end — Correct. In protein synthesis, each amino acid is first activated using ATP and then linked to its tRNA, which is called charging of tRNA. The amino acid binds at the 3′ end of the tRNA (the amino acid acceptor end).

Option (3) 5' end — Incorrect. The 5′ end does not hold the amino acid.

NCERT Extract:
Translation – “… tRNA has an anticodon loop that has bases complementary to the code, and it also has an amino acid acceptor end to which it binds to amino acids. tRNAs are specific for each amino acid (Figure 5.12).”