AP BIOLOGY

Detailed explanation-1: -As mentioned, sickle-cell anemia is the result of a change in a single nucleotide, and it represents just one class of mutations called point mutations. Changes in the DNA sequence can also occur at the level of the chromosome, in which large segments of chromosomes are altered.

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: -Types of Point Mutations. We are going to focus on the following point mutations: frameshift, silent, nonsense, and missense. Let’s start with a frameshift mutation, where there’s an insertion or deletion of one or more bases.

Detailed explanation-4: -A mutation (Section 14.1) is a change in the nucleotide sequence of a short region of a genome (Figure 14.1A). Many mutations are point mutations that replace one nucleotide with another; others involve insertion or deletion of one or a few nucleotides.