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: -A substitution mutation is a type of replication error during DNA replication which places the wrong nucleotide or sequence of nucleotides in the wrong position. A type of substitution mutation, a point mutation, occurs which a single nucleotide is substituted.

Detailed explanation-3: -Definition. A point mutation occurs in a genome when a single base pair is added, deleted or changed. While most point mutations are benign, they can also have various functional consequences, including changes in gene expression or alterations in encoded proteins.

Detailed explanation-4: -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.