Why Might a Point Mutation in DNA Make a Difference

Question

Why might a point mutation in DNA make a difference in the level of protein's activity?
A)It might result in a chromosomal translocation.
B)It might exchange one stop codon for another stop codon.
C)It might exchange one serine codon for a different serine codon.
D)It might substitute an amino acid in the active site.
E)It might substitute the N-terminus of the polypeptide for the C-terminus.

Accepted Answer

A point mutation in DNA that results in a substitution of an amino acid in the active site of the protein can change the way the protein interacts with its substrate, leading to a change in the protein's activity level. This is because the active site is the area of the protein where substrate binding and chemical reactions take place, and changing even one amino acid in this region can alter the shape and function of the protein.