This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
True about silent mutation in gene : (PGI Nov 2009) 
Select and explain. 
A. No change in mRNA, B. No change in Amino acid sequence in protein, C. No expression of protein, D. No change in expression of protein
B: No change in Amino acid sequence in protein
Answer: B: No change in Amino acid sequence in protein 
Explanation: Ans:B (No change in Amino acid sequence in protein) &D(No change in expression of protein) Silent MutationsThere may be no detectable effectQ because of the degeneracyQ of the code.This would be more likely if the changed base in the mRNA molecule were to be at the third nucleotide of a codon. Because of wobbleQ, the translation of a codon is least sensitive to a change at the third positionMissense MutationQ# A missense effect will occur when a different amino acid is incorporated' at the corresponding site in the protein molecule. This mistaken amino acid or missense, depending upon its location in the specific protein- might be acceptable, partially acceptable, or unacceptable degto the function of the protein molecule.Nonsense MutationQ In this a nonsense codon result in the prema ture termination of aminoacid incorporation into a peptide chain Si the production of only a fragment of intended protein molecule. The probability' is high that a prematurely terminated protein molecule or peptide fragment will not functionQ in its assigned role