Molecular Basis of Inheritance Question 77

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

[2003]

(a) A polypeptide of 25 amino acids will be formed

(b) A polypeptide of 24 amino acids will be formed

(c) Two polypeptides of 24 and 25 amino acids will be formed

(d) A polypeptide of 49 amino acids will be formed

Show Answer

Answer : b

Hints & Solution

(b) UAA is the stop codon. Therefore at 25th amino acid the synthesis of polypeptide stops. So, a polypeptide of 24 amino acids is formed.