1. Which type of mutation involves the replacement of a single nucleotide base with another in DNA? A) Missense mutation B) Nonsense mutation C) Silent mutation D) Frameshift mutation Answer: A) Missense mutation Rationale: A missense mutation involves the substitution of one nucleotide for another, which results in the change of an amino acid in the protein produced. 2. A frameshift mutation is best described as: A) The insertion or deletion of a nucleotide that does not alter the reading frame B) The substitution of one nucleotide for another C) The insertion or deletion of one or more nucleotides that alters the reading frame D) A mutation that has no effect on the amino acid sequence of a protein Answer: C) The insertion or deletion of one or more nucleotides that alters the reading frame Rationale: Frameshift mutations result from insertions or deletions of nucleotides that change the reading frame of the gene, often leading to significant changes in the protein product. 3. What is the consequence of a nonsense mutation in a gene? A) It changes an amino acid in the protein. B) It shortens the protein by introducing a premature stop codon. C) It has no effect on the protein. D) It extends the length of the protein. Answer: B) It shortens the protein by introducing a premature stop codon. Rationale: Nonsense mutations introduce a stop codon prematurely, which truncates the protein, potentially leading to loss of function. 4. Which mutation is likely to have the least effect on the function of a protein? A) Missense mutation B) Nonsense mutation