Question

What would happen if in a gene encoding a polypeptide of 50 amino acids, 25th codon (UAU) is mutated to UAA:

• A. A polypeptide of 24 amino acids will be formed
• B. Two polypeptides of 24 and 25 amino acids will be formed
• C. A polypeptide of 49 amino acids will be formed
• D. A polypeptide of 25 amino acids will be formed

Answer 1

Answer: (A)

A polypeptide of 24 amino acids will be formed

Answer 2

If the 25th codon (UAU) in a gene encoding a polypeptide of 50 amino acids is mutated to UAA, the likely outcome is that a polypeptide of 24 amino acids will be formed. The reason for this is that UAA is a stop codon, and when it is encountered during translation, it signals the termination of protein synthesis. Therefore, translation would terminate immediately upon encountering the UAA codon at position 25, resulting in a polypeptide that is 24 amino acids long.

So, the correct option is (A): A polypeptide of 24 amino acids will be formed.