MCQ Quiz- RNA Tumor Viruses

MCQ Quiz: RNA Tumor Viruses

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RNA tumor viruses, primarily a group within the retroviruses, are fascinating agents that subvert the central dogma of molecular biology to integrate into a host’s genome, sometimes leading to cancer. Understanding their unique life cycle, the enzymes they rely on, and how they transform cells is fundamental to both virology and oncology. This quiz for PharmD students will test your knowledge of the key principles of retroviral replication, the mechanisms of oncogenesis, and the viruses that link RNA to cancer.

1. RNA tumor viruses belong to which major family of viruses?

  • Herpesviridae
  • Adenoviridae
  • Retroviridae
  • Poxviridae

Answer: Retroviridae

2. What is the most critical and defining enzyme of all retroviruses, including RNA tumor viruses?

  • DNA polymerase
  • RNA polymerase
  • Reverse transcriptase
  • DNA ligase

Answer: Reverse transcriptase

3. The function of reverse transcriptase is to synthesize:

  • RNA from an RNA template.
  • Protein from an RNA template.
  • DNA from an RNA template.
  • RNA from a DNA template.

Answer: DNA from an RNA template.

4. After a retrovirus enters a host cell, its RNA genome is reverse-transcribed into a double-stranded DNA copy. This DNA copy is called a(n):

  • Episome
  • Plasmid
  • Provirus
  • Viroid

Answer: Provirus

5. For the viral genes to be expressed, the provirus must be integrated into the host cell’s chromosome. This integration is catalyzed by which viral enzyme?

  • Protease
  • Integrase
  • Reverse transcriptase
  • RNA polymerase

Answer: Integrase

6. The integrated provirus is then transcribed into new viral RNA by which enzyme?

  • The viral reverse transcriptase.
  • The host cell’s RNA polymerase II.
  • The viral integrase.
  • The host cell’s DNA polymerase.

Answer: The host cell’s RNA polymerase II.

7. “Acutely transforming” retroviruses are able to cause cancer rapidly because they:

  • Integrate into a specific site in the host genome.
  • Carry a viral oncogene (v-onc) in their own genome.
  • Have a very high rate of replication.
  • Suppress the host’s immune system.

Answer: Carry a viral oncogene (v-onc) in their own genome.

8. A viral oncogene (v-onc) is typically a mutated or dysregulated version of a host cell’s:

  • Tumor suppressor gene.
  • DNA repair gene.
  • Proto-oncogene.
  • Housekeeping gene.

Answer: Proto-oncogene.

9. Rous sarcoma virus (RSV) was a landmark discovery in cancer research. It is an acutely transforming retrovirus because it carries which oncogene?

  • myc
  • ras
  • src
  • erbB

Answer: src

10. “Slowly transforming” or “non-acute” retroviruses cause cancer over a much longer period. Their primary mechanism of oncogenesis is:

  • Carrying a viral oncogene.
  • Causing a chronic inflammatory state.
  • “Insertional mutagenesis,” where the provirus integrates near a host proto-oncogene, causing its overexpression.
  • Producing a toxic protein that kills healthy cells.

Answer: “Insertional mutagenesis,” where the provirus integrates near a host proto-oncogene, causing its overexpression.

11. Which of the following is the only known human retrovirus definitively associated with causing a specific cancer?

  • Human Immunodeficiency Virus (HIV)
  • Human T-cell Leukemia Virus-1 (HTLV-1)
  • Hepatitis C Virus (an RNA virus, but not a retrovirus)
  • Epstein-Barr Virus (a DNA virus)

Answer: Human T-cell Leukemia Virus-1 (HTLV-1)

12. HTLV-1 is the causative agent of which malignancy?

  • Kaposi’s sarcoma
  • Non-Hodgkin lymphoma
  • Adult T-cell Leukemia/Lymphoma (ATLL)
  • Cervical cancer

Answer: Adult T-cell Leukemia/Lymphoma (ATLL)

13. The simple retroviral genome consists of three main genes. They are, in order:

  • gag, pol, and env
  • env, pol, and src
  • tat, rev, and nef
  • pol, gag, and onc

Answer: gag, pol, and env

14. The gag gene in a retrovirus codes for:

  • The reverse transcriptase and integrase enzymes.
  • The envelope glycoproteins.
  • The structural proteins of the viral core (capsid, matrix).
  • The oncogene.

Answer: The structural proteins of the viral core (capsid, matrix).

15. The pol gene in a retrovirus codes for which key enzymes?

  • Reverse transcriptase, integrase, and protease.
  • The surface glycoproteins only.
  • The capsid and matrix proteins.
  • The protein kinase.

Answer: Reverse transcriptase, integrase, and protease.

16. The env gene in a retrovirus codes for:

  • The viral protease.
  • The structural core proteins.
  • The surface and transmembrane glycoproteins that mediate host cell entry.
  • The tRNA primer.

Answer: The surface and transmembrane glycoproteins that mediate host cell entry.

17. How does a retrovirus acquire a viral oncogene?

  • It is synthesized from scratch using the pol gene.
  • It is a normal part of all retroviral genomes.
  • It is picked up from a host cell by mistake during a previous replication cycle.
  • It is donated from another virus during a co-infection.

Answer: It is picked up from a host cell by mistake during a previous replication cycle.

18. A key difference between a cellular proto-oncogene (c-onc) and a viral oncogene (v-onc) is that the v-onc:

  • Is no longer under the control of the cell’s normal regulatory elements.
  • Often has mutations that make it constitutively active.
  • Is expressed at much higher levels.
  • All of the above.

Answer: All of the above.

19. Most acutely transforming retroviruses are “replication-defective.” This means that:

  • They cannot make a DNA copy of their genome.
  • The acquisition of the oncogene often causes a deletion in an essential viral gene (like env), so they need a “helper virus” to replicate.
  • They cannot integrate into the host chromosome.
  • They are unable to cause cancer.

Answer: The acquisition of the oncogene often causes a deletion in an essential viral gene (like env), so they need a “helper virus” to replicate.

20. A key leadership role for a pharmacist in a biotech company developing a new antiretroviral would be to understand:

  • The viral life cycle to identify potential new drug targets.
  • The company’s financial structure.
  • The marketing plan.
  • All of the above.

Answer: All of the above.

21. The “forging ahead” mindset in pharmacy means embracing new therapies, some of which are based on viral vectors derived from:

  • Retroviruses, for use in gene therapy.
  • Herpesviruses.
  • Adenoviruses.
  • Both A and C.

Answer: Both A and C.

22. A “business plan” for a new gene therapy would need to detail the science of the viral vector, which is a core principle of:

  • Virology.
  • Marketing.
  • Finance.
  • Human resources.

Answer: Virology.

23. The “regulation” of a new therapy that uses a retroviral vector is the responsibility of the:

  • DEA
  • FDA
  • CMS
  • EPA

Answer: The FDA

24. A “Clinical Decision Support” system could be designed to alert a physician if a patient’s cancer is known to be associated with:

  • A specific viral infection like HTLV-1.
  • A bacterial infection.
  • A fungal infection.
  • A parasitic infection.

Answer: A specific viral infection like HTLV-1.

25. A pharmacist’s knowledge of “DNA structure and DNA-protein interactions” is fundamental to understanding how:

  • The viral integrase enzyme interacts with and inserts the provirus into the host DNA.
  • A virus attaches to a cell.
  • The viral capsid is formed.
  • The viral envelope is acquired.

Answer: The viral integrase enzyme interacts with and inserts the provirus into the host DNA.

26. The “enzymes of DNA metabolism” like DNA ligase are part of the host cell’s machinery that a retrovirus can exploit during:

  • The integration of the provirus.
  • The repair of the host DNA after integration.
  • The replication of the host cell.
  • Both A and B.

Answer: Both A and B.

27. The “molecular biology technique” of creating a cDNA library is conceptually similar to the first step of a retroviral life cycle because both use the enzyme:

  • DNA polymerase.
  • RNA polymerase.
  • Reverse transcriptase.
  • DNA ligase.

Answer: Reverse transcriptase.

28. A key “policy” debate surrounding the use of retroviral vectors in gene therapy is:

  • Their high cost.
  • The long-term risk of insertional mutagenesis causing a secondary cancer.
  • Their effectiveness.
  • All of the above.

Answer: All of the above.

29. The “human resources” department of a virology research lab would need to recruit scientists with expertise in:

  • Retroviral replication and molecular biology.
  • Marketing.
  • Finance.
  • Only human relations.

Answer: Retroviral replication and molecular biology.

30. The “financials” of developing an antiretroviral drug are characterized by:

  • A low-risk, low-cost profile.
  • A high-risk, high-cost research and development process.
  • A guaranteed and rapid profit.
  • A simple and inexpensive clinical trial process.

Answer: A high-risk, high-cost research and development process.

31. Human Immunodeficiency Virus (HIV) is a retrovirus, but it does not typically cause cancer directly by insertional mutagenesis. Instead, it causes cancer by:

  • Carrying a viral oncogene.
  • Profoundly suppressing the immune system, which allows other oncogenic viruses (like KSHV and EBV) and cancers to develop.
  • Directly transforming B-cells.
  • Integrating next to a specific proto-oncogene.

Answer: Profoundly suppressing the immune system, which allows other oncogenic viruses (like KSHV and EBV) and cancers to develop.

32. The viral protease enzyme is a key drug target in HIV. Its function is to:

  • Integrate the viral DNA into the host chromosome.
  • Cleave the large viral polyproteins into their smaller, functional protein components.
  • Synthesize the viral DNA.
  • Mediate the entry of the virus into the cell.

Answer: Cleave the large viral polyproteins into their smaller, functional protein components.

33. The “Advocacy” role of a pharmacist is important in:

  • Promoting vaccination for preventable oncogenic viruses like HPV.
  • Advocating for access to expensive antiretroviral therapies.
  • Fighting the stigma associated with diseases like HIV/AIDS.
  • All of the above.

Answer: All of the above.

34. The “service” a clinical pharmacist provides for a patient with HIV (a retrovirus) or an HTLV-1-related cancer includes:

  • Managing complex drug regimens.
  • Monitoring for drug interactions and adverse effects.
  • Counseling on adherence.
  • All of the above.

Answer: All of the above.

35. A pharmacist’s understanding of “health disparities” is relevant because:

  • The burden of certain retroviral infections, like HIV, disproportionately affects minority populations.
  • Retroviral infections affect all populations equally.
  • It is not a relevant concept.
  • It helps in marketing new drugs.

Answer: The burden of certain retroviral infections, like HIV, disproportionately affects minority populations.

36. A key difference between the replication of a retrovirus and a typical RNA virus (like influenza) is that the retrovirus:

  • Replicates entirely in the cytoplasm.
  • Has a DNA intermediate in its life cycle.
  • Does not require a host cell.
  • Has an RNA-dependent RNA polymerase.

Answer: Has a DNA intermediate in its life cycle.

37. The term “endogenous retrovirus” refers to:

  • A retrovirus that is currently causing an active infection.
  • A retroviral provirus that has been integrated into the germline of a species and is passed down through generations.
  • A type of bacteriophage.
  • A virus that infects plants.

Answer: A retroviral provirus that has been integrated into the germline of a species and is passed down through generations.

38. The “long terminal repeats” (LTRs) at the ends of a provirus contain:

  • The coding sequences for the viral enzymes.
  • The gene for the envelope protein.
  • Powerful promoter and enhancer elements that drive the transcription of the viral genes.
  • The viral oncogene.

Answer: Powerful promoter and enhancer elements that drive the transcription of the viral genes.

39. The discovery by Howard Temin and David Baltimore that retroviruses contained the enzyme reverse transcriptase was a major scientific breakthrough because it:

  • Proved the central dogma of molecular biology (DNA -> RNA -> Protein) was always correct.
  • Challenged the central dogma by showing that genetic information could flow from RNA to DNA.
  • Was the basis for the development of penicillin.
  • Explained how all viruses replicate.

Answer: Challenged the central dogma by showing that genetic information could flow from RNA to DNA.

40. A “negotiation” with a payer for an expensive new antiretroviral drug would require a strong case based on:

  • Evidence of improved clinical outcomes and its place in treatment guidelines.
  • The high price of the drug alone.
  • The novelty of its mechanism.
  • The personal preference of the physician.

Answer: Evidence of improved clinical outcomes and its place in treatment guidelines.

41. In which “practice setting” is a pharmacist most likely to be a specialized expert in managing HTLV-1-related lymphoma?

  • A community pharmacy.
  • A hospital oncology or infectious disease service.
  • A mail-order pharmacy.
  • A supermarket pharmacy.

Answer: A hospital oncology or infectious disease service.

42. An “Electronic Health Record” (EHR) improves the care of a patient with a retroviral disease by:

  • Providing a clear, longitudinal record of viral loads, CD4 counts, and resistance tests.
  • Making it harder to access lab results.
  • Hiding the patient’s medication history.
  • Increasing the risk of prescribing errors.

Answer: Providing a clear, longitudinal record of viral loads, CD4 counts, and resistance tests.

43. A pharmacist’s understanding of “immunology” is critical because:

  • Retroviruses like HIV and HTLV-1 primarily infect cells of the immune system.
  • The immune response is the primary cause of cancer.
  • It is not relevant to virology.
  • The immune system cannot recognize viruses.

Answer: Retroviruses like HIV and HTLV-1 primarily infect cells of the immune system.

44. The “human factors” of managing a complex antiretroviral regimen for HIV involve:

  • Designing adherence aids and simplifying the regimen to reduce the risk of patient error.
  • Making the regimen as complex as possible.
  • Using tablets that are difficult to swallow.
  • Providing vague instructions.

Answer: Designing adherence aids and simplifying the regimen to reduce the risk of patient error.

45. The “antidotal therapy” for an overdose of a reverse transcriptase inhibitor would most likely be:

  • Naloxone.
  • Flumazenil.
  • Supportive care, as no specific chemical antidote exists.
  • N-acetylcysteine.

Answer: Supportive care, as no specific chemical antidote exists.

46. A key part of the “Introduction to Pharmacy Informatics” is understanding how an EHR can be used to:

  • Track and manage public health threats, such as an outbreak of a retroviral disease.
  • Increase the spread of infectious diseases.
  • Make health data less accessible.
  • Complicate the process of reporting diseases.

Answer: Track and manage public health threats, such as an outbreak of a retroviral disease.

47. A pharmacist’s knowledge of “chemotherapeutics” is relevant because the treatment for HTLV-1-associated lymphoma often involves:

  • Traditional cytotoxic chemotherapy regimens.
  • Antiretroviral therapy.
  • Both A and B may be used.
  • Neither A nor B is used.

Answer: Both A and B may be used.

48. “Gene therapy” often uses modified, replication-incompetent retroviruses as vectors. A major safety concern that must be addressed is:

  • The risk of the vector integrating into the host genome and causing a new cancer (insertional mutagenesis).
  • The high cost of the therapy.
  • The rapid effectiveness of the therapy.
  • The short duration of the therapeutic effect.

Answer: The risk of the vector integrating into the host genome and causing a new cancer (insertional mutagenesis).

49. The “DNA repair mechanisms” of the host cell are important for a retrovirus because:

  • They are needed to successfully integrate the provirus into the host chromosome.
  • They always recognize and destroy the provirus.
  • They are inhibited by the virus.
  • They are not relevant to the viral life cycle.

Answer: They are needed to successfully integrate the provirus into the host chromosome.

50. The ultimate principle of why pharmacists study RNA tumor viruses is that they represent a key intersection of:

  • Infectious disease, cancer biology, and molecular medicine.
  • Cardiology and pulmonology.
  • Toxicology and nephrology.
  • Geriatrics and pediatrics.

Answer: Infectious disease, cancer biology, and molecular medicine.

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