Which statement correctly defines codon, anticodon, and the wobble concept?

• A. A codon is a DNA triplet; the anticodon is on tRNA; wobble occurs at the first codon position.
• B. A codon is a three-nucleotide mRNA sequence encoding an amino acid; the anticodon on tRNA base-pairs with the codon; wobble allows non-Watson-Crick base pairing at the third codon position.
• C. A codon is a single nucleotide; anticodon pairs with tRNA; wobble is a concept about ribosome speed.
• D. A codon and anticodon both are amino acids; wobble is misreading.

Answer: (B)

Understanding how genetic information is read during translation helps make sense of codons, anticodons, and wobble. A codon is a three-nucleotide sequence on mRNA that specifies which amino acid will be added next. The anticodon is the complementary three-nucleotide sequence on tRNA that base-pairs with that codon to deliver the correct amino acid to the growing protein chain. Wobble is about flexibility at the third position of the codon, allowing certain non-Watson-Crick pairings between the codon and the tRNA anticodon. This means a single tRNA can recognize multiple codons that encode the same amino acid, thanks to looser pairing rules at the third base. Because of this, the statement accurately describes codons as three-nucleotide mRNA sequences that encode amino acids, anticodons as the tRNA component that base-pairs with the codon, and wobble as the allowance for non-standard pairing at the third codon position. The other descriptions mix up what codons and anticodons are (for example, treating codons as DNA triplets or single nucleotides, or saying wobble involves ribosome speed) or misstate where the anticodon sits, so they don’t fit the concept as a whole.