VIRUSES Questions and Answers pdf :-

1. Which of the following disinfectant is effective against viruses?

A. Hydrogen peroxide
B. Hypochlorite
C. Formaldehyde
D. All of these

Answer: D

2. Viruses largely lack metabolic machinery of their own to generate energy or to synthesize

A. protein
B. carbohydrate
C. alcohol
D. all of these

Answer: A

3. Viruses require __________ for growth.

A. bacteria
B. plants
C. animals
D. living cells

Answer: D

4. Reverse transcriptase is a useful enzyme to have when

A. an RNA virus converts its RNA to DNA
B. there are no host cells present
C. nutrients are scarce
D. spikes are forming in the new virus

Answer: A

5. The sequence of nucleic acid in a variety of viruses and viral host, will find more similarities

A. among different viruses than between viruses and their hosts
B. among different viral hosts than among different viruses
C. among different viral hosts than between viruses and their hosts
D. between viruses and their hosts than among different viruses

Answer: D

6. When a virus enters a cell but does not replicate immediately, the situation is called

A. lysogeny B. fermentation
C. symbiosis D. synergism

Answer: A

7. Usually viruses are separated into several large groups based primarily on

A. nature of the host
B. nucleic acid characteristics
C. capsid symmetry
D. diameter of the viroin or nucleocapsid

Answer: A

8. The first step in infection of a host bacterial cells by a phage is

A. adsorption B. absorption
C. penetration D. replication

Answer: A

9. Which of the following viruses has not been associated with human cancer?

A. Hepatitis C virus
B. Hepatitis B virus
C. Varicella-Zoster virus
D. Herpes simplex virus type 2

Answer: C

10. The viral nucleocapsid is the combination of

A. genome and capsid
B. capsid and spikes
C. envelope and capsid
D. capsomere and genome

Answer: A

11. Edward Jenner began inoculating humans with material from __________ lesions.

A. Smallpox
B. Avianpox
C. Cowpox
D. Chickenpox

Answer: C

12. The viruses in an attenuated vaccine

A. have no genome
B. continue to replicate
C. are usually larger than bacteria
D. is altered with chemicals

Answer: B

13. Enveloped viruses have a __________ shape.

A. icosahedral
B. helical
C. roughly spherical
D. complex

Answer: C

14. The envelope of which of the following viruses is derived from the host cell nucleus?

A. Paramyxoviruses
B. Retroviruses
C. Orthomyxoviruses
D. Herpesviruses

Answer: D

15. Which of the following is semi-continuous (diploid) cell line?

A. HeLa
B. HEp-2
C. WI-38
D. KB

Answer: C

16. Plant viruses may be cultivated in

A. tissue culture
B. cultures of separated cells
C. whole plants
D. all of these

Answer: D

17. The oncogene theory refers to

A. how chemicals inactivate viruses when applied
B. how viruses replicate in host cells
C. how viruses transform normal cells into tumor cells
D. none of these

Answer: C

18. In cell culture, measles virus may lead to

A. nuclear pyknosis
B. transformation of cells
C. syncytium formation
D. rounding and aggregation of cells

Answer: C

19. A change from lysogeny to lysis is generally induced by

A. ultraviolet light
B. chemicals
C. irradiation
D. all of these

Answer: A

20. The viral DNA is removed from the host’s chromosomes and the lytic cycle occurs. The process is called

A. spontaneous induction
B. inductive infection
C. resultant induction
D. spontaneous infection

Answer: A

21. The lysogenic state is governed by the activity of the regulatory region of the lambda phage genomes; this region is termed as

A. immunity repressor
B. immunity operon
C. operon repressor
D. none of these

Answer: B

22. The capsomeres consist of a number of proteins subunits or molecules called

A. protomers
B. caproprotein
C. procapsid
D. none of these

Answer: A

23. In order for a virus to replicate

A. the capsid must enter the host cell cytoplasm
B. the host cell must be undergoing mitosis
C. the genome must be released in the cytoplasm
D. the host cell must lack a cell membrane

Answer: C

24. Which of the following viruses belong to family Flaviviridae?

A. Rubella virus
B. Yellow fever virus
C. Hepatitis C virus
D. All of these

Answer: D

25. Which of the following viruses show/s transformation of infected cells?

A. Hepatitis B virus
B. Human T cell lymphotronic virus type I
C. Epstein-Barr virus
D. All of these

Answer: D

26. Which of the following may affect proteins and nucleic acids, but not viruses?

A. Denaturation
B. Enzyme treatment
C. Pressure
D. All of these

Answer: D

27. The viral DNA of the temperate phage, instead of taking over the functions of the cell’s genes, is incorporated into the host DNA and becomes a prophage in the bacterial chromosome, acting as a gene. This happens in

A. lysogeny
B. spontaneous induction
C. lytic phase
D. none of these

Answer: A

28. Which of the following statements is not true of viruses?

A. Viruses have been successfully grown in pure cultures in test tubes
B. All viruses are obligatory intracellular parasites
C. All viruses have either DNA or RNA as their genetic material
D. Viruses probably arose from small fragments of cellular chromosomes

Answer: A

29. Which of the following viruses belong/s to family caliciviridae?

A. Hepatitis B virus
B. Hepatitis D virus
C. Hepatitis E virus
D. All of these

Answer: C

30. In the simplest capsid, there is a capsomere at each of the 12 vertices; this capsomere, which is surrounded by five other capsomeres, is termed a

A. penton
B. polyhedra
C. icosahedral
D. helical

Answer: A

VIRUSES Questions and Answers ::

31. The size of viruses is usually measured in

A. centimeters
B. micrometers
C. nanometers
D. millimeters

Answer: C

32. The temperate phage that have no site specificity for insertion and may even be able to insert multiple copies of their DNA into a single bacterial chromosome is

A. ? phage enzyme
B. ? DNA
C. Phage Mu
D. Phage Mn

Answer: C

33. Enzyme neuraminidase is carried by which of the following viruses?

A. Human immunodeficiency virus
B. Epstein-Barr virus
C. Influenza virus
D. Adenovirus

Answer: C

34. Lysozyme (an endolysin) which will lyse the bacterial cell, releasing the mature virions is present in

A. immediate early phage genes
B. late genes
C. delayed early genes
D. all of these

Answer: B

35. Which of the following is continuous cell line?

A. HeLa
B. HEp-2
C. KB
D. All of these

Answer: D

36. The repressor protein, since the cell is resistant to lysis from externally infecting phage, is also called

A. immunity repressor
B. immunity operon
C. operon repressor
D. none of these

Answer: A

37. Which of the following virus is susceptible to chloroform?

A. Herpes
B. Influenza
C. Measles
D. All of these

Answer: D

38. Group E phages have

A. single stranded DNA
B. double stranded DNA
C. single stranded RNA
D. double stranded DNA

Answer: C

39. The temperate phage possesses a gene that codes for a repressor protein which makes the cell resistant to lysis initiated by

A. the prophage
B. lytic infection by other viruses
C. Both (a) and (b)
D. none of these

Answer: C

40. The bacterial viruses having head made up of large capsomeres, but no tail is morphologically classified as

A. A
B. B
C. C
D. D

Answer: D

41. The most complex type of bacterial viruses having hexagonal head, a rigid tail with a contractile sheath and tall fibers is morphologically classified as

A. A
B. B
C. C
D. D

Answer: A

42. Which of the following is not true of virions?

A. Reproduce independently
B. Contain DNA
C. Contain RNA
D. Are extracellular

Answer: A

43. Bacteriophages have been used widely in genetic research, since they are the smallest and simplest biological entities capable of

A. self-replication
B. duplication
C. self-duplication
D. multiplication

Answer: A

44. Lesions on chorioallantoic membrane are produced by

A. Herpes B virus
B. Vaccinia virus
C. Herpes simplex virus
D. all of these

Answer: D

45. Which one is not useful in the treatment of viruses except

A. acyclovir
B. interferon
C. penicillin
D. antibodies

Answer: C

46. The infected cells continue to reproduce themselves as well as the virus, and the mature virions are extruded from the cell surface continuously over a long period of time. This type of release mechanism is called a

A. productive infection
B. inductive infection
C. resultant infection
D. all of these

Answer: A

47. What kind of embryo is often used for viral assays?

A. Mouse
B. Rat
C. Cat
D. Chicken

Answer: D

48. The envelope of an enveloped virus is derived from

A. the mitochondrion of the cell
B. the cell membrane
C. the endoplasmic reticulum of the cell
D. none of these

Answer: B

49. The most popular indirect method of counting virus particles is by

A. hemagglutination assay
B. plaque-assay
C. counting plaque-forming units
D. colony counting

Answer: A

50. Which of the following viruses belong to family Hepadnaviridae?

A. Hepatitis A virus
B. Hepatitis B virus
C. Hepatitis D virus
D. All of these

Answer: B

51. Inclusion bodies of measles virus are

A. intracytoplasmic
B. intranuclear
C. both (a) and (b)
D. none of these

Answer: C

52. The most efficient way to enclose a space is within a/an

A. sphere
B. cube
C. icosahedron
D. helix

Answer: C

53. Which of the following is an example of rod-shaped viruses having their capsomeres arranged helically and not in the stacked ring?

A. Bateriophage M13
B. Bateriophage MV-L2
C. Bateriophage T2
D. Bateriophage T4

Answer: A

54. During the first 10 minutes after injection of phage DNA, no phage can be recovered by disrupting the infected bacterium. This is termed as

A. eclipse period
B. rise period
C. latent period
D. burst size

Answer: A

55. The function of a viral capsid is

A. protection against the viral genome from physical and enzymatic destruction
B. providing binding sites that enable the virus to attach to specific receptor sites on the host cell
C. serving as a vehicle of transmission from one host to another
D. all of the above

Answer: D

56. Which of the following oncogenic viruses was first detected?

A. Rous sarcoma virus.
B. Epstein-Barr virus
C. Herpes simplex virus type 2
D. Human T cell leukaemia virus

Answer: A

57. The yield of phage per bacterium is called the

A. eclipse size
B. latent size
C. burst size
D. none of these

Answer: C

58. Which of the following viruses are relatively thermostable?

A. Human immunodeficiency virus
B. Rubella virus
C. Hepatits A virus
D. Influenza virus

Answer: C

59. The time from infection until lysis is called as

A. eclipse period
B. rise period
C. latent period
D. burst size

Answer: C

60. Virus reproduces in living cells by

A. replication
B. duplication
C. multiplication
D. all of these

Answer: A

61. Which of the following virus is enveloped?

A. Adeno
B. Herpes
C. Polio
D. None of these

Answer: B

62. Which of the following viruses can rescue adenovirus in simian cells?

A. Rabies
B. Vaccinia
C. Simian virus 40
D. Cytomegalovirus

Answer: C

63. The phage components begin to assemble into mature phages only after the synthesis of

A. structural protein
B. nucleic acid
C. Both (a) and (b)
D. amino acids

Answer: C

64. Which of the following bacteriophage is said to have banal symmetry?

A. T2
B. T4
C. T6
D. all of these

Answer: D

65. Which of the following statements is correct?

A. Up to 10% of human tumours have a viral risk factor
B. Up to 40% of human tumours have a viral risk factor
C. Up to 30% of human tumours have a viral risk factor
D. Up to 20% of human tumours have a viral risk factor

Answer: D

66. Which of the following are obligate intracellular parasites?

A. Chlamydia
B. Viruses
C. Rickettsia
D. All of these

Answer: D

67. Viruses can be purified based on their size and density by using

A. gradient centrifugation
B. differential centrifugation
C. precipitation
D. none of these

Answer: A

68. The extracellular phage number increases until a constant titer at the end of the multiplication cycle. This time interval is termed as

A. eclipse period
B. rise period
C. latent period
D. burst size

Answer: B

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