AP BIOLOGY

Detailed explanation-1: -Sometimes, gene variants (also known as mutations) prevent one or more proteins from working properly. By changing a gene’s instructions for making a protein, a variant can cause a protein to malfunction or to not be produced at all.

Detailed explanation-2: -Causes of Mutations Some mutations occur when a mistake is made during DNA replication or transcription. Other mutations occur because of environmental factors. Anything in the environment that causes a mutation is known as a mutagen. Examples of mutagens are shown in Figure below.

Detailed explanation-3: -While mutations always change the DNA sequence, they do not always cause a change in the resulting protein or an obvious effect on the organism. This can occur because most amino acids can be coded by two or more different codons.

Detailed explanation-4: -A mutation is a change in a genetic sequence. Mutations include changes as small as the substitution of a single DNA building block, or nucleotide base, with another nucleotide base. Meanwhile, larger mutations can affect many genes on a chromosome.

Detailed explanation-5: -Phenotypic mutations are errors that occur during protein synthesis. These errors lead to amino acid substitutions that give rise to abnormal proteins.