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: -Nonsense Mutation A nonsense mutation occurs in DNA when a sequence change gives rise to a stop codon rather than a codon specifying an amino acid. The presence of the new stop codon results in the production of a shortened protein that is likely non-functional.

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: -Missense Mutation A missense mutation is a DNA change that results in different amino acids being encoded at a particular position in the resulting protein. Some missense mutations alter the function of the resulting protein.

Detailed explanation-5: -Insertion or deletion of one or two bases changes the reading frame from the point of insertion or deletion. However, such mutations are referred to as frameshift insertion or deletion mutations. So, the statement in option C is wrong.