Ch. 15 Understanding Mutation and Cancer

Which of the following best defines a gene mutation?

• A change in the number of chromosomes

• A permanent alteration in the DNA sequence of a gene

• The process of DNA replication

• The repair of damaged proteins

What is the primary function of DNA polymerase during DNA replication?

• To synthesize RNA primers

• To add nucleotides to a growing DNA strand

• To unwind the DNA double helix

• To repair thymine dimers

Which type of mutation involves the substitution of a single nucleotide base with another?

• Frameshift mutation

• Point mutation

• Chromosomal inversion

• Duplication

What is the role of the p53 protein in cells?

• It synthesizes DNA

• It repairs cell membranes

• It regulates the cell cycle and can induce apoptosis

• It transports oxygen

Which of the following is a common cause of thymine dimers in DNA?

• Ionizing radiation

• Ultraviolet (UV) light

• High temperature

• Viral infection

Which DNA repair mechanism is responsible for removing and replacing damaged bases caused by deamination?

• Mismatch repair

• Base excision repair

• Nucleotide excision repair

• Homologous recombination

Which of the following best describes a proto-oncogene?

• A gene that repairs DNA

• A normal gene that can become an oncogene due to mutations

• A gene that suppresses tumors

• A gene that codes for ribosomal RNA

Which enzyme is primarily responsible for joining Okazaki fragments during DNA replication?

• DNA helicase

• DNA ligase

• DNA polymerase

• RNA primase

Which of the following is an example of a mutagen?

• Water

• Ethidium bromide

• Glucose

• Oxygen

What is the result of a frameshift mutation in a gene?

• No change in the protein sequence

• A single amino acid substitution

• A shift in the reading frame, altering downstream amino acids

• The removal of an entire chromosome