A codon substitution that changes the amino acid but does not change the length of the protein is called

A codon substitution that changes the amino acid but does not change the length of the protein is called

• A. Missense mutation
• B. Nonsense mutation
• C. Silent mutation
• D. Frameshift mutation

Answer: (A)

Mutations can affect the protein sequence in different ways, and this item tests how a single codon change can alter which amino acid is used without changing the protein's length. A missense mutation is a single nucleotide substitution that changes the codon to one encoding a different amino acid, so the protein sequence changes at that position but the total number of amino acids remains the same. This matches the described scenario. In contrast, a nonsense mutation converts a codon to a stop signal, producing a shorter, truncated protein; a silent mutation changes the codon to another that codes for the same amino acid, leaving the amino acid sequence and length unchanged; and a frameshift mutation arises from insertions or deletions that shift the reading frame, typically altering downstream amino acids and often changing the protein length.

Mutations can affect the protein sequence in different ways, and this item tests how a single codon change can alter which amino acid is used without changing the protein's length. A missense mutation is a single nucleotide substitution that changes the codon to one encoding a different amino acid, so the protein sequence changes at that position but the total number of amino acids remains the same. This matches the described scenario. In contrast, a nonsense mutation converts a codon to a stop signal, producing a shorter, truncated protein; a silent mutation changes the codon to another that codes for the same amino acid, leaving the amino acid sequence and length unchanged; and a frameshift mutation arises from insertions or deletions that shift the reading frame, typically altering downstream amino acids and often changing the protein length.