A nonsense mutation typically results in

A nonsense mutation typically results in

• A. A longer protein
• B. A shorter, usually nonfunctional protein
• C. No change in protein length
• D. A completely new protein

Answer: (B)

A nonsense mutation introduces a premature stop codon during translation, so the ribosome terminates early and the protein is shortened. That missing portion often includes essential functional regions, rendering the protein nonfunctional or unstable. In many cases the mRNA itself is targeted for degradation through nonsense-mediated decay, reducing or eliminating protein production. Because of these effects, the typical outcome is a shorter, usually nonfunctional protein. This does not yield a longer protein, nor leave the length unchanged, nor produce a completely new protein.

A nonsense mutation introduces a premature stop codon during translation, so the ribosome terminates early and the protein is shortened. That missing portion often includes essential functional regions, rendering the protein nonfunctional or unstable. In many cases the mRNA itself is targeted for degradation through nonsense-mediated decay, reducing or eliminating protein production. Because of these effects, the typical outcome is a shorter, usually nonfunctional protein. This does not yield a longer protein, nor leave the length unchanged, nor produce a completely new protein.