Which of the following mutations involves replacing an amino acid with a different one due to a codon change?

Which of the following mutations involves replacing an amino acid with a different one due to a codon change?

• A. Silent mutation
• B. Missense mutation
• C. Deletion mutation
• D. Inversion mutation

Answer: (B)

A missense mutation is defined as a type of mutation where a single nucleotide change in the DNA sequence results in the substitution of one amino acid for another in the protein product. This occurs when the altered codon codes for a different amino acid, potentially affecting the structure and function of the resulting protein. In contrast, a silent mutation does not change the amino acid sequence, even though there is a change in the nucleotide sequence, because it still codes for the same amino acid. Deletion mutations involve the removal of nucleotides from the DNA sequence, which can lead to frameshifts and alterations in the entire amino acid sequence downstream. Inversion mutations involve a segment of DNA being flipped in orientation, which may not directly cause a change in amino acids but can affect overall gene expression and function. Thus, the defining characteristic of a missense mutation is the direct replacement of one amino acid with another, resulting from the change in the codon.

A missense mutation is defined as a type of mutation where a single nucleotide change in the DNA sequence results in the substitution of one amino acid for another in the protein product. This occurs when the altered codon codes for a different amino acid, potentially affecting the structure and function of the resulting protein.

In contrast, a silent mutation does not change the amino acid sequence, even though there is a change in the nucleotide sequence, because it still codes for the same amino acid. Deletion mutations involve the removal of nucleotides from the DNA sequence, which can lead to frameshifts and alterations in the entire amino acid sequence downstream. Inversion mutations involve a segment of DNA being flipped in orientation, which may not directly cause a change in amino acids but can affect overall gene expression and function.

Thus, the defining characteristic of a missense mutation is the direct replacement of one amino acid with another, resulting from the change in the codon.