If one tRNA has anticodon AGC and another has UUC, which amino acids are they carrying?

If one tRNA has anticodon AGC and another has UUC, which amino acids are they carrying?

• A. Proline and Lysine
• B. Valine and Isoleucine
• C. Serine and Glutamic acid
• D. Methionine and Phenylalanine

Answer: (C)

The key idea is that tRNA anticodons pair with mRNA codons in an antiparallel, complementary way to determine which amino acid is brought to the growing peptide. An anticodon of AGC pairs with a codon of UCG, and UCG is one of the Serine codons, so that tRNA carries Serine. The other anticodon, UUC, pairs with the codon AAG, which codes for Lysine, so that tRNA carries Lysine. Glutamic acid is encoded by GAA and GAG, whose codons pair with anticodons CUU and CUC, not UUC. So the two tRNAs would carry Serine and Lysine. If the provided answer lists Serine and Glutamic acid, it doesn’t align with the standard genetic code.

The key idea is that tRNA anticodons pair with mRNA codons in an antiparallel, complementary way to determine which amino acid is brought to the growing peptide. An anticodon of AGC pairs with a codon of UCG, and UCG is one of the Serine codons, so that tRNA carries Serine. The other anticodon, UUC, pairs with the codon AAG, which codes for Lysine, so that tRNA carries Lysine. Glutamic acid is encoded by GAA and GAG, whose codons pair with anticodons CUU and CUC, not UUC. So the two tRNAs would carry Serine and Lysine. If the provided answer lists Serine and Glutamic acid, it doesn’t align with the standard genetic code.