What type of mutation involves the substitution of a single nucleotide that results in a different amino acid?

A mutation that involves the substitution of a single nucleotide, leading to a different amino acid in the resulting protein, is known as a point mutation. This type of mutation directly affects the sequence of the DNA at a specific location, where one nucleotide is replaced by another.

In this context, if the substitution occurs in a region of the DNA that codes for a protein, it can lead to an altered amino acid sequence during translation. The new amino acid may be similar or different in properties from the original, which can potentially change protein function depending on the role of that specific amino acid in the protein's structure or activity.

While nonsense mutations involve substitutions that lead to a premature stop codon, and frameshift mutations cause a shift in the reading frame of the genetic code, they do not simply result from a single nucleotide substitution in the way a point mutation does. Chromosomal mutations refer to larger-scale changes in the structure or number of chromosomes and are also distinct from point mutations. Therefore, the classification of the mutation as a point mutation is appropriate when referring to the simple substitution of one nucleotide for another that results in an amino acid change.