Question

question 3 of 10
which mutation would likely have the smallest effect on a protein?
a. an insertion at the beginning of the coding region of a gene
b. a substitution that causes a change far from an enzymes active site
c. a deletion near the codons that code for the active site of a protein
d. a frameshift mutation near the center of a gene

Explanation:

• Option A: An insertion at the beginning of the coding region of a gene is likely to cause a frameshift mutation. This will change the reading frame of the mRNA, leading to a completely different amino - acid sequence downstream of the insertion. This can have a large - scale impact on the protein structure and function.
• Option B: A substitution that causes a change far from an enzyme's active site. Since the active site is the region where the enzyme binds to its substrate and catalyzes the reaction, a change far from this site is less likely to disrupt the enzyme's function. Amino - acid substitutions can sometimes be conservative (similar amino - acid properties) or in non - critical regions of the protein.
• Option C: A deletion near the codons that code for the active site of a protein. The active site is crucial for the protein's function. A deletion near this region can disrupt the three - dimensional structure of the active site, affecting substrate binding and catalytic activity.
• Option D: A frameshift mutation near the center of a gene. Frameshift mutations change the reading frame of the mRNA. Near the center of a gene, this will affect a large portion of the protein sequence (from the point of mutation to the end of the protein), likely leading to a non - functional or severely altered protein.

Answer:

B. A substitution that causes a change far from an enzyme's active site