AP BIOLOGY

Detailed explanation-1: -Nonsense: A nonsense variant is another type of substitution. Instead of causing a change in one amino acid, however, the altered DNA sequence results in a stop signal that prematurely signals the cell to stop building a protein.

Detailed explanation-2: -A nucleotide substitution that changes the corresponding amino acid in the protein is called a nonsynonymous substitution (denoted as KA), whereas a nucleotide substitution that does not change the amino acid in the protein is called a synonymous substitution (denoted as KS).

Detailed explanation-3: -A silent substitution is a point mutation that changes one DNA nucleobase to another but does not change the amino acid for which the mutated nucleobase codes.

Detailed explanation-4: -A silent mutation is one of the three types of substitution mutations (also called point mutations)-along with nonsense and missense. Specifically, a silent mutation occurs when a change in the DNA sequence of a gene does not affect the subsequent amino acid sequence of the protein it codes for.

Detailed explanation-5: -Point Mutations A nucleotide change in the DNA that does not result in an amino acid change in the protein is called a “synonomous” or “silent” mutation (see Figure 3.3).