MCQ Quiz- Mutation and DNA Repair

MCQ Quiz: Mutation and DNA Repair

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Mutations, or changes in the DNA sequence, are the ultimate source of genetic variation, but they can also be the root cause of diseases like cancer. To combat the constant threat of DNA damage, cells have evolved a sophisticated arsenal of DNA repair pathways. For pharmacists, understanding how mutations arise and how they are repaired is fundamental to grasping disease pathophysiology, hereditary cancer syndromes, and the mechanisms of many anticancer drugs. This quiz for PharmD students will test your knowledge of the essential principles of mutation and the cellular machinery that guards the genome.

1. A “mutation” is best defined as a permanent change in the:

  • Protein sequence of a cell.
  • RNA sequence of a gene.
  • DNA sequence of an organism.
  • Chromatin structure.

Answer: DNA sequence of an organism.

2. A mutation that changes a single nucleotide base pair is called a:

  • Frameshift mutation
  • Chromosomal translocation
  • Point mutation
  • Deletion

Answer: Point mutation

3. A “silent” mutation is a point mutation that:

  • Creates a premature stop codon.
  • Changes the amino acid sequence.
  • Does not change the resulting amino acid sequence due to the degeneracy of the genetic code.
  • Inserts a new base into the sequence.

Answer: Does not change the resulting amino acid sequence due to the degeneracy of the genetic code.

4. A point mutation that results in a codon that codes for a different amino acid is known as a:

  • Nonsense mutation
  • Silent mutation
  • Missense mutation
  • Frameshift mutation

Answer: Missense mutation

5. A “nonsense” mutation is a point mutation that:

  • Changes one amino acid to another.
  • Results in a premature stop codon.
  • Has no effect on the protein.
  • Deletes a single base pair.

Answer: Results in a premature stop codon.

6. A “frameshift” mutation is caused by:

  • A single base substitution.
  • The insertion or deletion of a number of nucleotides that is not a multiple of three.
  • A mutation in a promoter sequence.
  • The inversion of a large chromosomal segment.

Answer: The insertion or deletion of a number of nucleotides that is not a multiple of three.

7. The primary purpose of DNA repair pathways is to:

  • Introduce new mutations to drive evolution.
  • Correct errors and damage in the DNA to maintain genomic integrity.
  • Regulate the cell cycle.
  • Promote gene expression.

Answer: Correct errors and damage in the DNA to maintain genomic integrity.

8. “Base Excision Repair” (BER) is a pathway that primarily corrects:

  • Bulky, helix-distorting lesions.
  • DNA double-strand breaks.
  • Small, non-helix-distorting base lesions, such as deaminated cytosine (uracil).
  • Mismatched bases after replication.

Answer: Small, non-helix-distorting base lesions, such as deaminated cytosine (uracil).

9. The first enzyme to act in Base Excision Repair is a(n):

  • DNA Polymerase
  • DNA Ligase
  • AP Endonuclease
  • DNA Glycosylase

Answer: DNA Glycosylase

10. “Nucleotide Excision Repair” (NER) is the primary pathway in humans for repairing:

  • Single-base mismatches.
  • Uracil in DNA.
  • Bulky lesions that distort the DNA helix, such as pyrimidine dimers caused by UV light.
  • Double-strand breaks.

Answer: Bulky lesions that distort the DNA helix, such as pyrimidine dimers caused by UV light.

11. The genetic disease Xeroderma Pigmentosum is caused by a defect in which DNA repair pathway?

  • Mismatch Repair
  • Base Excision Repair
  • Nucleotide Excision Repair
  • Homologous Recombination

Answer: Nucleotide Excision Repair

12. The “Mismatch Repair” (MMR) system is responsible for:

  • Repairing damage from UV light.
  • Correcting errors made by DNA polymerase that escape the proofreading function during replication.
  • Rejoining double-strand breaks.
  • Removing uracil from DNA.

Answer: Correcting errors made by DNA polymerase that escape the proofreading function during replication.

13. Defects in mismatch repair genes (like MSH2, MLH1) are the cause of which hereditary cancer syndrome?

  • Li-Fraumeni syndrome
  • Hereditary retinoblastoma
  • Lynch syndrome (Hereditary Non-Polyposis Colorectal Cancer)
  • Von Hippel-Lindau disease

Answer: Lynch syndrome (Hereditary Non-Polyposis Colorectal Cancer)

14. Which of the following is the most cytotoxic form of DNA damage?

  • A silent mutation.
  • A single-base mismatch.
  • A double-strand break.
  • An AP site.

Answer: A double-strand break.

15. “Non-Homologous End Joining” (NHEJ) is a major pathway for repairing double-strand breaks. It is considered:

  • Highly accurate and error-free.
  • “Quick and dirty” because it is fast but often results in small insertions or deletions.
  • Dependent on a sister chromatid template.
  • A form of direct reversal repair.

Answer: “Quick and dirty” because it is fast but often results in small insertions or deletions.

16. The other major pathway for repairing double-strand breaks is “Homologous Recombination” (HR), which is:

  • Fast but error-prone.
  • Highly accurate because it uses the undamaged sister chromatid as a template for repair.
  • The primary repair mechanism for UV damage.
  • A type of base excision repair.

Answer: Highly accurate because it uses the undamaged sister chromatid as a template for repair.

17. The tumor suppressor genes BRCA1 and BRCA2 are essential for which DNA repair pathway?

  • Nucleotide Excision Repair
  • Mismatch Repair
  • Homologous Recombination
  • Base Excision Repair

Answer: Homologous Recombination

18. A woman who inherits a germline mutation in the BRCA1 gene has a significantly increased lifetime risk for:

  • Lung cancer.
  • Breast and ovarian cancer.
  • Colorectal cancer.
  • Leukemia.

Answer: Breast and ovarian cancer.

19. The anticancer drugs known as “PARP inhibitors” are most effective in tumors that have a defect in:

  • Mismatch Repair.
  • Homologous Recombination (e.g., BRCA1/2 mutations).
  • Nucleotide Excision Repair.
  • Base Excision Repair.

Answer: Homologous Recombination (e.g., BRCA1/2 mutations).

20. The 3′ to 5′ exonuclease activity of DNA polymerase is its ________ function.

  • Polymerizing
  • Proofreading
  • Helicase
  • Ligating

Answer: Proofreading

21. A “somatic” mutation occurs in a body cell and will not be passed on to offspring, while a “germline” mutation occurs in a sperm or egg cell and:

  • Is also not heritable.
  • Can be passed on to the next generation.
  • Only affects the parent.
  • Is always silent.

Answer: Can be passed on to the next generation.

22. Deamination of cytosine is a common form of spontaneous DNA damage that results in the formation of which base?

  • Thymine
  • Guanine
  • Adenine
  • Uracil

Answer: Uracil

23. If uracil is not repaired by a DNA glycosylase from the BER pathway before replication, it will lead to what type of point mutation?

  • A transversion (purine to pyrimidine).
  • A transition (C-G to T-A).
  • A deletion.
  • An insertion.

Answer: A transition (C-G to T-A).

24. A pharmacist’s knowledge of “oncogenes and tumor suppressors” is directly linked to understanding mutation because:

  • Activating mutations create oncogenes, and inactivating mutations disable tumor suppressors.
  • The two topics are unrelated.
  • All mutations lead to the activation of tumor suppressors.
  • All mutations inactivate oncogenes.

Answer: Activating mutations create oncogenes, and inactivating mutations disable tumor suppressors.

25. A key “leadership” role for a pharmacist in a precision oncology service is to:

  • Advocate for the appropriate use of genetic testing to identify mutations in DNA repair genes that can guide therapy.
  • Make all final treatment decisions.
  • Manage the clinic’s budget.
  • Perform genetic counseling.

Answer: Advocate for the appropriate use of genetic testing to identify mutations in DNA repair genes that can guide therapy.

26. The “forging ahead” mindset in pharmacy means embracing personalized medicine, such as using the __________ to select a PARP inhibitor.

  • Patient’s tumor mutation status
  • Patient’s insurance plan
  • Patient’s age
  • Patient’s weight

Answer: The patient’s tumor mutation status

27. A “business plan” for a new biotech company might focus on developing a novel drug that:

  • Inhibits a specific DNA repair enzyme found only in cancer cells.
  • Promotes DNA damage.
  • Is a broad-spectrum antibiotic.
  • Is a new type of pain reliever.

Answer: Inhibits a specific DNA repair enzyme found only in cancer cells.

28. The “regulation” of a new diagnostic test that detects mutations in DNA repair genes is the responsibility of the:

  • DEA
  • FDA
  • CMS
  • EPA

Answer: The FDA

29. An “analytics and reporting system” in a cancer center could be used to:

  • Identify all patients with a BRCA mutation to ensure they have received appropriate counseling and screening.
  • Track the pharmacy’s inventory.
  • Schedule patient appointments.
  • Create a marketing plan.

Answer: Identify all patients with a BRCA mutation to ensure they have received appropriate counseling and screening.

30. A “Clinical Decision Support” system is critical for preventing harm by:

  • Alerting a physician to a patient’s known mutation in a DNA repair gene that could affect their response to chemotherapy.
  • Dispensing a medication.
  • Billing for a hospital stay.
  • It cannot use this type of data.

Answer: Alerting a physician to a patient’s known mutation in a DNA repair gene that could affect their response to therapy.

31. A “policy” decision to recommend genetic screening for Lynch syndrome in all patients with colorectal cancer is based on the high prevalence of ________ defects in these tumors.

  • Mismatch repair
  • Homologous recombination
  • Nucleotide excision repair
  • Base excision repair

Answer: Mismatch repair

32. The “enzymes of DNA metabolism,” such as polymerases and ligases, are the workhorses of:

  • DNA replication.
  • DNA repair.
  • Both DNA replication and repair.
  • Only transcription.

Answer: Both DNA replication and repair.

33. A “molecular biology technique” like PCR is essential for:

  • Amplifying a specific gene from a patient’s DNA to screen it for mutations.
  • Repairing a double-strand break.
  • Measuring the level of a protein.
  • Cloning an entire organism.

Answer: Amplifying a specific gene from a patient’s DNA to screen it for mutations.

34. A “health disparity” could arise if genetic testing for mutations in DNA repair genes is:

  • Not equitably accessible to all patient populations.
  • Covered by all insurance plans.
  • Offered with culturally competent genetic counseling.
  • Used to guide personalized therapy for all patients who need it.

Answer: Not equitably accessible to all patient populations.

35. A pharmacist’s role in “drug use and prevention” is relevant because substances like tobacco smoke contain carcinogens that cause:

  • DNA damage and mutations.
  • Improved cell health.
  • Enhanced DNA repair.
  • No biological effects.

Answer: DNA damage and mutations.

36. “Direct reversal” is a simple form of DNA repair that:

  • Removes a patch of DNA.
  • Chemically reverses the DNA damage without cutting the backbone.
  • Uses a template to fix the damage.
  • Is always error-prone.

Answer: Chemically reverses the DNA damage without cutting the backbone.

37. The “SOS response” in bacteria is a form of error-prone DNA repair that is induced by:

  • The presence of antibiotics.
  • Extensive DNA damage.
  • A lack of nutrients.
  • A change in temperature.

Answer: Extensive DNA damage.

38. The tumor suppressor p53 is a “guardian of the genome” that responds to DNA damage by:

  • Halting the cell cycle.
  • Activating DNA repair pathways.
  • Inducing apoptosis if damage is too severe.
  • All of the above.

Answer: All of the above.

39. A key “human resources” consideration for a genetic counseling service is:

  • Hiring counselors with the expertise and empathy to explain complex mutation and repair information.
  • The brand of computer used.
  • The clinic’s holiday party schedule.
  • The number of parking spaces available.

Answer: Hiring counselors with the expertise and empathy to explain complex mutation and repair information.

40. A “negotiation” with a payer for an expensive PARP inhibitor would be strongest if it is supported by:

  • A positive genetic test for a BRCA mutation and data from clinical trials showing a survival benefit.
  • The high price of the drug alone.
  • The novelty of the drug’s mechanism.
  • The personal preference of the physician.

Answer: A positive genetic test for a BRCA mutation and data from clinical trials showing a survival benefit.

41. The “service” of pharmacogenomics in a pharmacy involves understanding how inherited variations, sometimes in _________, can affect drug safety and efficacy.

  • DNA repair genes
  • Drug metabolizing enzymes
  • Drug transporter genes
  • All of the above

Answer: All of the above

42. The “Eukaryotic and Prokaryotic DNA Replication” course provides the foundation for understanding:

  • How replication errors are a major source of mutations that require repair.
  • How transcription works.
  • How proteins are synthesized.
  • How genes are regulated.

Answer: How replication errors are a major source of mutations that require repair.

43. A “special recombination” pathway like V(D)J recombination creates DNA breaks that must be repaired. A defect in the ________ repair pathway can lead to severe immunodeficiency.

  • Mismatch Repair
  • Base Excision Repair
  • Non-Homologous End Joining
  • Nucleotide Excision Repair

Answer: Non-Homologous End Joining

44. A “chemotherapeutic” like cisplatin works by creating DNA cross-links. Cancer cells can become resistant if they upregulate their:

  • DNA replication machinery.
  • DNA repair capacity, particularly the NER pathway.
  • Growth factor signaling.
  • Angiogenesis pathways.

Answer: DNA repair capacity, particularly the NER pathway.

45. The “cloning” of a human DNA repair gene into a yeast cell allows researchers to:

  • Study its function in a simple, controlled model system.
  • Create a new species.
  • Cure cancer in the yeast.
  • Produce a human protein for therapeutic use.

Answer: Study its function in a simple, controlled model system.

46. A pharmacist’s “leadership” is shown by advocating for the integration of _______ into routine cancer care.

  • Genetic testing for hereditary DNA repair defects
  • Higher prices for all medications
  • Less patient counseling
  • A return to paper-based records

Answer: Genetic testing for hereditary DNA repair defects

47. “Epigenetic” changes like DNA methylation can influence DNA repair by:

  • Causing mutations directly.
  • Silencing the expression of key DNA repair genes.
  • Enhancing the expression of all DNA repair genes.
  • Having no effect on the process.

Answer: Silencing the expression of key DNA repair genes.

48. In which “practice setting” is a pharmacist most likely to manage a patient on a PARP inhibitor?

  • A community pharmacy.
  • A specialized oncology clinic.
  • A mail-order pharmacy.
  • A supermarket pharmacy.

Answer: A specialized oncology clinic.

49. An “Electronic Health Record” (EHR) improves safety by:

  • Allowing for the structured storage of a patient’s genetic test results, including mutations in DNA repair genes.
  • Hiding lab results from the pharmacist.
  • Increasing the number of transcription errors.
  • Making it harder to communicate with the care team.

Answer: Allowing for the structured storage of a patient’s genetic test results, including mutations in DNA repair genes.

50. The ultimate principle of why pharmacists study mutation and DNA repair is that these processes are:

  • Central to cancer biology and the mechanism of action for many targeted anticancer drugs.
  • An interesting but minor topic in medicine.
  • The cause of all infectious diseases.
  • The primary target for all medications.

Answer: Central to cancer biology and the mechanism of action for many targeted anticancer drugs

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