UGU and UGC are codons for the amino acid cysteine, and this amino acid can form disulfide bonds in a polypeptide. UGG is the codon for the amino acid tryptophan, which contains no sulfur atom. UGA functions as a stop signal. The DNA triplet code for the 10th amino acid in a particular polypeptide is ACA. Which single-base substitutions in this triplet code would mean that no disulfide bond is formed with the 10th amino acid in the polypeptide?
- AACC and ACG
- BACG and ACT
- CACT and ACC
- DACT only