Final answer:
An anticodon is a sequence of three nucleotides found on transfer RNA (tRNA), which pairs with a complementary codon sequence on messenger RNA (mRNA) (option 2) during protein synthesis.
Step-by-step explanation:
An anticodon is located on transfer RNA (tRNA). An anticodon is a consecutive sequence of three nucleotides on a tRNA molecule that is complementary to a specific codon on an mRNA molecule. During protein synthesis, each tRNA anticodon base pairs with one of the mRNA codons to add the corresponding amino acid to the growing polypeptide chain.
The process of base pairing is essential for the translation of genetic information from the language of nucleic acids to the language of proteins. With the correct amino acid attached, tRNA molecules transport these amino acids to the ribosome, where the anticodon-codon interaction occurs, ensuring that the correct amino acid is incorporated into the protein.