AP BIOLOGY

Detailed explanation-1: -Base substitutions are the simplest type of gene-level mutation, and they involve the swapping of one nucleotide for another during DNA replication. For example, during replication, a thymine nucleotide might be inserted in place of a guanine nucleotide.

Detailed explanation-2: -Substitution mutations can be good, bad, or have no effect. They cause three specific types of point mutation: silent, missense, and nonsense mutations. A silent mutation is one where the function of the protein is not changed. A missense mutation codes for the wrong protein.

Detailed explanation-3: -Nonsense mutation: A nonsense mutation is also a change in one DNA base pair. Instead of substituting one amino acid for another, however, the altered DNA sequence prematurely signals the cell to stop building a protein. This type of mutation results in a shortened protein that may function improperly or not at all.

Detailed explanation-4: -Mutations can be of many types, such as substitution, deletion, insertion, and translocation.