Which statement best defines a point mutation?

Which statement best defines a point mutation?

• A. A single nucleotide change in DNA
• B. A mutation that changes the number of chromosomes
• C. A mutation that duplicates a gene
• D. A mutation that affects lipid synthesis

Answer: (A)

A single nucleotide change in DNA is the defining feature of a point mutation. This means a change at a single base pair, which can alter the codon in a gene, potentially changing an amino acid or, in some cases, having no effect at all (a silent mutation). Point mutations are the smallest-scale genetic changes, and they contrast with larger-scale alterations like changes in chromosome number (too many or too few chromosomes), gene duplications (copying a whole gene), or mutations that primarily affect metabolic pathways such as lipid synthesis. Those latter descriptions refer to broader genomic changes or functional consequences, not the basic definition of a point mutation.

A single nucleotide change in DNA is the defining feature of a point mutation. This means a change at a single base pair, which can alter the codon in a gene, potentially changing an amino acid or, in some cases, having no effect at all (a silent mutation). Point mutations are the smallest-scale genetic changes, and they contrast with larger-scale alterations like changes in chromosome number (too many or too few chromosomes), gene duplications (copying a whole gene), or mutations that primarily affect metabolic pathways such as lipid synthesis. Those latter descriptions refer to broader genomic changes or functional consequences, not the basic definition of a point mutation.