Which mutation replaces a single base and may alter the gene product?

Which mutation replaces a single base and may alter the gene product?

• A. Substitution Mutation
• B. Frameshift Mutation
• C. Insertion Mutation
• D. Deletion Mutation

Answer: (A)

A single-base change that replaces one nucleotide is a substitution mutation. This type swaps out a base, creating a new codon that can lead to a different amino acid or a stop signal, and thus may alter the gene product. Because of the genetic code’s redundancy, some substitutions don’t change the protein at all (silent mutations), but the key point is that it involves replacing a single base and has the potential to affect the protein. Insertion and deletion mutations involve adding or removing bases, which shifts the reading frame or changes many codons, not just a single base, so they don’t match the description.

A single-base change that replaces one nucleotide is a substitution mutation. This type swaps out a base, creating a new codon that can lead to a different amino acid or a stop signal, and thus may alter the gene product. Because of the genetic code’s redundancy, some substitutions don’t change the protein at all (silent mutations), but the key point is that it involves replacing a single base and has the potential to affect the protein. Insertion and deletion mutations involve adding or removing bases, which shifts the reading frame or changes many codons, not just a single base, so they don’t match the description.