Question

Occasionally, a mutation is discovered that suppresses termination and allows a chain-terminating codon to be read as an amino acid code without changing the codon. What is the most likely effect of these mutations?

a. Nonsense mutation
b. Silent mutation
c. Missense mutation
d. Frame-shift mutation

Answer 1

A mutation that allows a stop codon to be read as an amino acid without changing the codon is likely a missense mutation, which affects the protein's sequence by swapping one amino acid for another.

Step-by-step explanation:

The type of mutation where a chain-terminating codon is read as an amino acid code without changing the codon is most likely to be a missense mutation. In a missense mutation, one amino acid is swapped for another in the protein sequence, which could lead to changes in protein structure and function. This contrasts with a nonsense mutation, which converts an amino acid codon into a stop codon, leading to premature termination of translation and possibly resulting in a nonfunctional protein.

Meanwhile, a silent mutation does not alter the amino acid sequence of the protein and has no effect. Lastly, a frameshift mutation results from the insertion or deletion of nucleotides that shift the reading frame, altering all subsequent amino acids and often resulting in a nonfunctional protein.