Translation fundamentals — The anticodon sequence is a defining structural feature found on which molecule?

Introduction:
Decoding of mRNA into protein depends on accurate base pairing between codons and anticodons. This question asks you to identify the macromolecule that carries the anticodon used in this process.

Given Data / Assumptions:

• Codons are triplets on mRNA.
• Anticodons are complementary triplets that recognize codons.
• Translation occurs on ribosomes with help from adaptors.

Concept / Approach:
The anticodon resides on transfer RNA (tRNA). Each tRNA carries a specific amino acid at its 3′ end and has an anticodon loop that recognizes the corresponding codon on mRNA, ensuring incorporation of the correct amino acid into the growing polypeptide chain.

Step-by-Step Solution:

Verification / Alternative check:
Crystal structures of tRNA bound to ribosomes clearly show the anticodon loop base pairing with mRNA codons in the decoding center.

Why Other Options Are Wrong:

• mRNA: contains codons, not anticodons.
• Ribosome/rRNA: provide scaffolding and catalysis, not the anticodon.
• DNA polymerase: functions in DNA replication, unrelated to translation decoding.

Common Pitfalls:
Mixing up codon vs anticodon terminology; codon = mRNA, anticodon = tRNA.

Final Answer:
tRNA.