What defines a missense mutation?

What defines a missense mutation?

• A. It introduces a stop codon
• B. It changes one amino acid in a protein
• C. It does not affect protein function
• D. It results in gene deletion

Answer: (B)

A missense mutation is defined by its effect on the protein sequence, specifically by changing a single nucleotide in the DNA sequence, which consequently alters the amino acid that is incorporated into the protein during translation. This change can occur when the original codon, which specifies a particular amino acid, is replaced with a different codon that codes for a different amino acid. The significance of a missense mutation lies in its potential to affect the structure and function of the resulting protein. While some missense mutations may lead to slight changes that do not adversely affect protein function, others can have substantial impacts on protein activity or stability, thereby influencing an organism's phenotype. Therefore, the critical aspect of a missense mutation is that it introduces a new amino acid into the protein sequence, shifting the overall sequence without terminating it, unlike a nonsense mutation that creates a stop codon or deletions that remove parts of the gene and alter gene expression or product entirely.

A missense mutation is defined by its effect on the protein sequence, specifically by changing a single nucleotide in the DNA sequence, which consequently alters the amino acid that is incorporated into the protein during translation. This change can occur when the original codon, which specifies a particular amino acid, is replaced with a different codon that codes for a different amino acid.

The significance of a missense mutation lies in its potential to affect the structure and function of the resulting protein. While some missense mutations may lead to slight changes that do not adversely affect protein function, others can have substantial impacts on protein activity or stability, thereby influencing an organism's phenotype. Therefore, the critical aspect of a missense mutation is that it introduces a new amino acid into the protein sequence, shifting the overall sequence without terminating it, unlike a nonsense mutation that creates a stop codon or deletions that remove parts of the gene and alter gene expression or product entirely.