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: -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-3: -Sickle cell is caused by a base-substitution when the adenine base in GAG is replaced by a thymine base, changing the triplet to GTG. The normal triplet when transcribed and translated codes for the amino acid glutamic acid. When the base substitution occurs, the amino acid that is translated is now valine.

Detailed explanation-4: -A point mutation is a mutation that takes place on a single nucleotide in the DNA sequence. It is also called a base-pair mutation or a base-pair substitution. A point mutation that does not lead to any harmful effects and does not change the sequence of amino acids in the protein is called a silent mutations.