Question

Which point mutation changes a codon but does not alter the resulting amino acid?

• A. Missense mutation
• B. Nonsense mutation
• C. Silent mutation
• D. Frameshift mutation

Hint:

Silent mutation = \textbf{No change in protein}. Think: Different codon, same amino acid.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Point mutations are genetic changes where a single nucleotide base is substituted, inserted, or deleted.
The effect on the protein depends on whether the new codon codes for the same or a different amino acid.
Step 2: Detailed Explanation:
A Silent mutation is a type of point mutation where the DNA sequence is changed, but the resulting amino acid remains the same.
This phenomenon occurs because the genetic code is degenerate (or redundant), meaning that multiple codons can code for the same amino acid.
For example, if the codon GGG (Glycine) mutates to GGA, it still codes for Glycine, so the protein structure remains unaffected.
In contrast:
- Missense mutation results in a different amino acid.
- Nonsense mutation creates a premature stop codon.
- Frameshift mutation shifts the entire reading frame by adding or deleting bases.
Step 3: Final Answer:
The mutation that does not alter the amino acid is the Silent mutation.