Question

What would happen if a gene encoding a polypeptide of 50 amino acids 26${}^{th}$ (UAC) is mutated to codon UAA ?

• A. A poypeptides of 24 amino adds will be formed
• B. Two poll/peptides of 24 and 25 amino acids will be farmed
• C. A polypeptides of 25 amino acids will be formed
• D. A polypeptides of 49 amino acids will be formed

Answer 1

The correct option is C A polypeptides of 25 amino acids will be formed

In translation process, various start codon and stop codon are present. The most common start codon is AUG. The stop codons are UAA, UAG, and UGA. Wherever the stop codon appears in the chain, translation process will terminate. Since in this polypeptide chain, UAA is substituted in 26th position, so the chain will not progress further and will be translated to 25th position only.

Hence answer is option C.