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