Question

Correlate the codons of the mRNA strand with the amino acids of the polypeptide translated.

5’ AUG ACC UUU CACU UCG UGU AA3’ → mRNA

Met - Thr - Phe - His - Phe - Val → Translated polypeptide

Infer any three properties of the genetic code with examples from the above information.

Answer 1

Based on the mRNA sequence and the polypeptide chain, the following three properties can be inferred:

1. Non-overlapping: The genetic code is read in a linear sequence of triplets. Each base is a part of only one codon; for example, in the sequence AUG ACC, the ‘G’ belongs exclusively to the first codon and the ‘A’ to the second. One base is never shared between two adjacent codons.
2. Commaless: The genetic code is continuous. There are no gaps or “punctuation” marks (commas) between consecutive codons. Once the translation begins at AUG, the mRNA is read triplet by triplet without skipping any nucleotides until the stop codon is reached.
3. Degenerate: Some amino acids are specified by more than one codon. While each codon corresponds to only one amino acid, many amino acids (like Phenylalanine in previous examples) have multiple codons that represent them, providing a buffer against mutations.