Translation — Which two structural features of a tRNA directly convert a triplet mRNA codon into its corresponding amino acid during protein synthesis?

Introduction:
tRNA is the adaptor that “reads” mRNA codons and delivers the matching amino acid. This question asks which two parts of tRNA are directly responsible for decoding and amino acid attachment, the core of the adaptor hypothesis in translation.

Given Data / Assumptions:

• tRNA has a cloverleaf secondary structure and L-shaped tertiary fold.
• Each tRNA ends with a conserved 3′-CCA sequence.
• Ribosomes align tRNA anticodons with mRNA codons.

Concept / Approach:
The anticodon loop base-pairs with the complementary mRNA codon to ensure proper decoding. The 3′ CCA acceptor end is the site where aminoacyl-tRNA synthetases esterify the cognate amino acid to the 3′-terminal ribose, creating aminoacyl-tRNA for peptide bond formation.

Step-by-Step Solution:

Verification / Alternative check:
Mutations in anticodon change decoding; editing and recognition elements near the acceptor stem control charging specificity, confirming these features’ direct roles.

Why Other Options Are Wrong:

Common Pitfalls:
Assuming all loops have equal roles; confusing synthetase recognition sites with ribosomal decoding sites.

Final Answer:
Anticodon loop + 3′ CCA acceptor end.