- 1. Virology is the branch of science that focuses on the study of viruses and viral diseases. Viruses are small infectious agents that can only replicate inside living cells of other organisms. Virologists investigate the structure, classification, evolution, and interactions of viruses, as well as the mechanisms by which viruses cause disease in their hosts. Understanding virology is crucial in the development of treatments and vaccines for viral infections, and in preventing the spread of viral diseases. The field of virology is constantly evolving as new viruses emerge and existing viruses mutate, posing ongoing challenges to public health and medicine.
What is a virus?
A) A type of bacteria
B) A plant cell
C) A small infectious agent that replicates only inside the living cells of other organisms.
D) A single-celled organism
- 2. What is the protein coat surrounding the genetic material of a virus called?
A) Capsid
B) Nucleocapsid
C) Envelope
D) Glycoprotein
- 3. Which of the following is a method of viral entry into a host cell?
A) Aerobic respiration
B) Photosynthesis
C) Mitosis
D) Endocytosis
- 4. What is the outermost layer of some viruses that is composed of lipids and proteins?
A) Nucleocapsid
B) Spike protein
C) Capsid
D) Envelope
- 5. What is the name of the enzyme that retroviruses use to convert RNA into DNA?
A) Ligase
B) RNA polymerase
C) DNA polymerase
D) Reverse transcriptase
- 6. What is antigenic drift in viruses?
A) Rapid mutation leading to new strains
B) Sudden change in host specificity
C) Gradual accumulation of mutations in viral genes over time
D) Antibody production against viral proteins
- 7. Which type of genetic material is found in retroviruses?
A) Protein
B) Lipid
C) DNA
D) RNA
- 8. Which viral disease has been completely eradicated through vaccination?
A) Smallpox
B) Zika virus
C) Ebola virus
D) HIV/AIDS
- 9. Which of the following is a common symptom of viral infections?
A) Broken bones
B) High blood pressure
C) Yellowish skin
D) Fever
- 10. Who is acknowledged for officially beginning the field of virology as a distinct discipline?
A) Ernest William Goodpasture
B) Martinus Beijerinck
C) Frederick Twort
D) Rosalind Franklin
- 11. What term did Martinus Beijerinck use to describe the novel pathogen causing tobacco mosaic disease?
A) Vaccinia virus
B) Contagium vivum fluidum
C) Poliovirus
D) Bacteriophage
- 12. Who first discovered the full structure of the tobacco mosaic virus?
A) Wendell Meredith Stanley
B) Heinz Fraenkel-Conrat
C) Rosalind Franklin
D) Ernst Ruska
- 13. In what year did Dmitri Ivanovsky use the Chamberland filter to study tobacco mosaic virus?
A) 1913
B) 1906
C) 1884
D) 1892
- 14. Who independently discovered bacteriophages in 1917?
A) Félix d'Herelle
B) Paul Frosch
C) Frederick Twort
D) Dmitri Ivanovsky
- 15. Which virus was the first to be crystallized, allowing its structure to be elucidated in detail?
A) Tobacco mosaic virus
B) Poliovirus
C) Hepatitis B virus
D) Influenza virus
- 16. Who were the first to grow poliovirus in cultured cells from aborted human embryonic tissue?
A) John Franklin Enders, Thomas Weller, and Frederick Robbins
B) Ross Granville Harrison, E. Steinhardt, C. Israeli
C) H. B. Maitland and M. C. Maitland
D) Ernest William Goodpasture and Alice Miles Woodruff
- 17. Who invented the electron microscope in 1931?
A) John Franklin Enders and Thomas Weller
B) Wendell Meredith Stanley and Rosalind Franklin
C) Ernst Ruska and Max Knoll
D) Frederick Twort and Félix d'Herelle
- 18. In which year did Wendell Meredith Stanley find that the tobacco mosaic virus was mostly made of protein?
A) 1963
B) 1935
C) 1957
D) 1941
- 19. Who first isolated HIV, a retrovirus, in 1983?
A) Howard Temin
B) Luc Montagnier's team at the Pasteur Institute
C) Michael Houghton's team at Chiron Corporation
D) Baruch Blumberg
- 20. Which virus was discovered by Baruch Blumberg in 1963?
A) Human immunodeficiency virus (HIV)
B) Equine arterivirus
C) Hepatitis B virus
D) Bovine viral diarrhoea
- 21. Who described the first retrovirus in 1965?
A) Michael Houghton
B) Baruch Blumberg
C) Luc Montagnier
D) Howard Temin
- 22. Which scientist's work enabled the production of an effective polio vaccine?
A) Jonas Salk
B) John Franklin Enders
C) Hilary Koprowski
D) Frederick Robbins
- 23. Which viruses were among the first to be discovered and are useful for studying virus biology?
A) Rotaviruses
B) Bacteriophages
C) Coronaviruses
D) Influenza viruses
- 24. What suffix is used for genera in the ICTV classification system?
A) -viricetes
B) -viridae
C) -virales
D) -virus
- 25. What solution is commonly used in buoyant density centrifugation to form a gradient?
A) Caesium chloride
B) Coomasie blue
C) Ethidium bromide
D) Polyacrylamide gel
- 26. What type of genome do Group III viruses have in the Baltimore classification?
A) ssDNA
B) (+)ssRNA
C) dsDNA-RT
D) dsRNA
- 27. Which type of virus genome is associated with Group VI in the Baltimore classification?
A) dsDNA viruses
B) dsRNA viruses
C) (−)ssRNA viruses
D) ssRNA-RT viruses
- 28. Which technique is not as common in nature but is useful in laboratories to study viral genes?
A) Cloning
B) Phage display techniques
C) RNA silencing
D) Recombination
- 29. Which suffix is used for suborders in the ICTV classification system?
A) -virus
B) -virales
C) -virineae
D) -viricetes
- 30. Who grew influenza and several other viruses in fertilized chicken eggs in 1931?
A) H. B. Maitland and M. C. Maitland
B) E. Steinhardt, C. Israeli, and R.A. Lambert
C) Ross Granville Harrison
D) Ernest William Goodpasture and Alice Miles Woodruff
- 31. Which method is used when virus suspensions remain contaminated after differential centrifugation?
A) Sanger sequencing
B) Electrophoresis
C) Low speed centrifugation
D) Buoyant density centrifugation
- 32. What technique was used to quickly manufacture tests at the start of the COVID-19 pandemic?
A) RNA silencing
B) Phage display techniques
C) Recombination
D) Cloning
- 33. Which staining method is used for visualizing nucleic acids in electrophoresis?
A) Radioactive labeling
B) Ethidium bromide
C) PHYLIP software
D) Coomasie blue
- 34. Which suffix is used for virus families in the ICTV classification system?
A) -virus
B) -virales
C) -viricetes
D) -viridae
- 35. How many realms of viruses have been defined by the ICTV as of 2021?
A) 6
B) 39
C) 17
D) 10
- 36. In the Baltimore classification, which group includes viruses with double-stranded DNA genomes?
A) Group III
B) Group I
C) Group II
D) Group IV
- 37. How are results of the FFA expressed?
A) As infectious dose 50%.
B) As plaque forming units per milliliter.
C) As focus forming units per milliliter (FFU/mL).
D) As viral load in copies per milliliter.
- 38. What are bacteriophages informally called when they reproduce in bacteria?
A) Viruses
B) Recombinants
C) Plasmids
D) Phages
- 39. In what year was the International Committee on Taxonomy of Viruses (ICTV) formed?
A) 1975.
B) 1980.
C) 1966.
D) 1999.
- 40. Who demonstrated that purified tobacco mosaic virus RNA and protein coat can assemble to form functional viruses?
A) Heinz Fraenkel-Conrat and Robley Williams
B) Ernst Ruska and Max Knoll
C) Wendell Meredith Stanley
D) Bernal and Fankuchen
- 41. What type of centrifuge is typically used to concentrate viruses?
A) Ordinary laboratory microcentrifuges
B) Low speed centrifuges with a top speed of 10,000 rpm
C) Ultracentrifuges with a top speed around 100,000 rpm
D) Centrifuges used for blood separation
- 42. In what year was the bacteriophage first discovered by Frederick Twort?
A) 1898
B) 1915
C) 1957
D) 1946
- 43. What classification system is used to supplement the traditional hierarchy for viruses?
A) The Lwoff-Horne-Tournier system.
B) The ICTV 15-rank classification system.
C) The Linnaean hierarchical system.
D) The Baltimore classification system.
- 44. What is a common type of cloning vector used in virology?
A) Laboratory modified plasmids
B) RNA molecules
C) Recombinant DNA
D) Bacteriophages
- 45. Which virus was first grown on a large scale for vaccine production in the 1950s?
A) Poliovirus
B) Hepatitis B virus
C) Tobacco mosaic virus
D) Influenza virus
- 46. Which group in the Baltimore classification includes viruses with double-stranded DNA that use reverse transcriptase?
A) Group III
B) Group II
C) Group VII
D) Group I
- 47. Which group in the Baltimore classification includes viruses with single-stranded RNA that is positive-sense?
A) Group VI
B) Group V
C) Group VII
D) Group IV
- 48. Which software is commonly used to draw phylogenetic trees?
A) Next-generation sequencing (NGS)
B) Ethidium bromide
C) PHYLIP
D) Coomasie blue
- 49. In the Baltimore classification, which group includes viruses with single-stranded RNA that is negative-sense?
A) Group V
B) Group VI
C) Group VII
D) Group IV
- 50. Which suffix is used for classes in the ICTV classification system?
A) -virus
B) -virales
C) -viridae
D) -viricetes
- 51. As of 2021, how many species of viruses have been defined by the ICTV?
A) 233
B) 10,434
C) 39
D) 65
- 52. How many orders of viruses have been defined by the ICTV as of 2021?
A) 168
B) 39
C) 233
D) 65
- 53. What technique uses bacteriophages for screening protein DNA sequences?
A) Cloning
B) Phage display techniques
C) Recombination
D) RNA silencing
- 54. What is the process called when genes from different parents are switched in viruses with segmented genomes?
A) Reassortment
B) RNA silencing
C) Cloning
D) Recombination
- 55. What was commonly used before PCR to confirm viral infections?
A) Immunofluorescence.
B) Microfluidic tests.
C) Complement fixation tests.
D) Lateral flow tests.
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