micro bio14

43. The site at which a virus has infected and subsequently lysed the infected cell, releasing its progeny to infect and lyse surrounding cells, thereby forming a "clear zone", is referred to as A. a burst area. B. a lyse area. C. a plaque. D. a dead zone.

C. a plaque.

31. Diseases of short duration frequently followed by long-term immunity are referred to as A. intermittent infections. B. chronic infections. C. acute infections. D. persistent infections.

C. acute infections.

9. The common species name of the virus is based on the A. presence or absence of a nuclear membrane. B. type of nucleic acid it contains. C. disease the virus causes. D. geographic area it is found.

C. disease the virus causes.

20. For which of the following processes are enzymes not required? A. replication B. translation C. maturation D. self-assembly

D. self-assembly

11. A key feature of all viral infections is the A. integration of viral DNA into host DNA. B. disintegration of host DNA. C. addition of a lipid membrane to the virus. D. separation of viral nucleic acid from the capsid.

D. separation of viral nucleic acid from the capsid.

6. There are _______ families of DNA containing viruses that infect vertebrates. A. two B. four C. five D. seven

D. seven

4. The terms isometric, icosahedral and pleomorphic refer to A. viral life cycles. B. forms of nucleic acid. C. types of viral envelopes. D. shapes of viruses.

D. shapes of viruses.

15. Attachment of animal viruses to the host cell may be by means of A. a tail. B. the envelope. C. a capsid. D. spikes.

D. spikes.

5. Animal viruses are divided into a number of families whose names end in A. -virus. B. -viridae. C. -viscous. D. -eieio.

B. -viridae.

1. The nucleocapsid is composed of A. DNA and RNA and protein. B. DNA or RNA and protein. C. protein located in the nucleus. D. nucleic acid in the ribosome.

B. DNA or RNA and protein.

44. Which of the following is not a characteristic of normal cells? A. They grow as a monolayer. B. They grow as multiple layers. C. They undergo a limited number of divisions and then die. D. They stick tightly to the surface of glass culture dishes.

B. They grow as multiple layers.

49. Prions A. consist of a special nucleocapsid. B. are made of protein only. C. are made of RNA only. D. are made of dsRNA and protein.

B. are made of protein only.

22. In addition to lysis, animal viruses may exit the host cell by A. extrusion. B. budding. C. fission. D. fusion.

B. budding.

2. Enveloped viruses A. just require a stamp. B. have an outer lipid bilayer membrane containing various proteins. C. are surrounded by an additional layer of carbohydrate. D. envelope a cell.

B. have an outer lipid bilayer membrane containing various proteins.

27. In latent infections, the virions are A. constantly produced. B. only produced during reactivation. C. produced slowly. D. continually being slowly budded out.

B. only produced during reactivation.

52. Viroids cause disease in A. animals. B. plants. C. bacteria. D. fungus.

B. plants.

10. The family to which the Rhinovirus belongs is the A. Picornaviridae. B. Enterovirus. C. Enteroviridae. D. Picornavirus.

A. Picornaviridae.

33. Genetic exchange in segmented viruses that allows a zoonotic virus to infect humans is termed A. antigenic shift. B. hemagglutination. C. genetic reassortment. D. antigenic drift.

A. antigenic shift.

36. The changes that occur in virally-infected cells are characteristic for a particular virus and are referred to as the A. cytopathic effect. B. phenotypic effect. C. genotypic expression. D. cytology.

A. cytopathic effect

3. The term "segmented" refers to viruses that A. may contain several pieces of RNA. B. have an icosahedral-shaped capsid. C. are linked together before budding out. D. have an envelope.

A. may contain several pieces of RNA.

40. The approximate viral concentration of a sample may be determined by A. quantal assay. B. endpoint assay. C. the titer. D. the lysate assay.

A. quantal assay.

51. Viroids characteristically are composed of A. ssRNA. B. dsRNA. C. ssDNA. D. dsDNA.

A. ssRNA.

37. After growth in tissue culture, the infected cells lyse and the virus may be harvested from A. the liquid supernatant after centrifugation, the lysate. B. the remainder. C. the quantal layer. D. the monolayer.

A. the liquid supernatant after centrifugation, the lysate.

45. Plant viruses enter the host plant via A. wound sites. B. specific receptors. C. nonspecific receptors. D. seeds.

A. wound sites.

21. Cells infected with animal viruses lyse because A. the release of the virions depletes the cell of energy. B. the virus releases enzymes that lyse the cell. C. functions necessary for cell survival are not carried out and the cell dies. D. the virus RNA and cellular protein interact to kill the cell.

C. functions necessary for cell survival are not carried out and the cell dies.

50. Prions affect the A. respiratory system. B. gastrointestinal tract. C. nervous system. D. lymphatic system.

C. nervous system.

29. The genome of retroviruses is made of A. ssDNA. B. dsDNA. C. ssRNA. D. dsRNA.

C. ssRNA.

32. Retroviruses are unique in that they A. replicate in nervous system cells. B. do not have a capsid. C. use RNA as a template to make DNA. D. use DNA as a template to make RNA.

C. use RNA as a template to make DNA.

47. Transmission of plant viruses by insects can occur from A. viruses associated with insect mouth parts. B. viruses circulating but not multiplying in the insect's body. C. viruses that multiply within the body of the insect. D. All of the above

D. All of the above

54. Spongiform encephalopathy occurs in A. humans. B. cattle. C. sheep. D. All of the choices are correct.

D. All of the choices are correct.

53. Prions are A. a form of RNA virus. B. a form of DNA virus. C. a viroid. D. an infectious protein.

D. an infectious protein.

13. The condition in which the virus infects and persists within the host with no obvious harm is A. disease. B. colonization. C. adaptation. D. balanced pathogenicity.

D. balanced pathogenicity.

35. Viruses may not be cultivated in A. live organisms. B. embryonated chicken eggs. C. tissue culture. D. blood agar.

D. blood agar.

19. Bacteriophages and animal viruses A. both may enter a host cell by endocytosis. B. both may enter a host cell by fusion. C. both involve entry of the entire nucleocapsid. D. differ because bacteriophages leave the capsid outside the cell, while animal virus entry involves the entry of the whole nucleocapsid.

D. differ because bacteriophages leave the capsid outside the cell, while animal virus entry involves the entry of the whole nucleocapsid.

39. If reasonably pure preparations of virus are available, the number of virus present may be determined by A. photocolorimetry. B. gas chromatography. C. light microscopy. D. electron microscopy.

D. electron microscopy.

18. When an enveloped virus adsorbs to the host cell with its protein spikes, the virions are taken into the cell by the process of A. penetration. B. production. C. fusion. D. endocytosis.

D. endocytosis

7. There are _______ families of RNA containing viruses that infect vertebrates. A. two B. five C. seven D. fourteen

D. fourteen

28. The best known chronic infection involves A. chickenpox. B. herpes. C. hepatitis A. D. hepatitis B.

D. hepatitis B.

17. Resistance of some animals to certain viral diseases is based on A. lack of spikes for attachment. B. phagocytosis of the virus by the host cell. C. the presence of the viral envelope. D. lack of specific receptors on the host cell.

D. lack of specific receptors on the host cell.

23. In the region of budding, the inside of the plasma membrane becomes coated with A. enzymes. B. carbohydrates. C. steroids. D. matrix proteins.

D. matrix proteins.

42. One group of animal viruses that are able to agglutinate red blood cells are the A. coronavirus. B. retrovirus. C. reovirus. D. myxovirus.

D. myxovirus.

12. An infection in which the virus is continually present in the body is referred to as A. acute . B. balanced. C. determinant. D. persistent.

D. persistent.

38. Normal tissue taken from animals and prepared immediately as media for viral growth is termed a(n) A. advantageous group. B. monolayer culture. C. plaque. D. primary culture.

D. primary culture.

48. Prions A. replicate by converting normal host proteins into prion proteins. B. responsible for "Mad Cow Disease" can cause a similar disease in humans. C. can be transmitted by consumption of dried or cooked prions. D. that cause spongiform encephalopathy have the same amino acids but different folding properties from PrPc. E. All of the above

E. All of the above

46. Plant viruses may be transmitted by A. worms. B. contaminated seeds. C. humans. D. insects. E. All of the choices are correct.

E. All of the choices are correct.

41. The concentration of virus that infects or kills 50% of the host cells is referred to as the A. LD50. B. ID50. C. ID100. D. LD100. E. LD50 AND ID50.

E. LD50 AND ID50.

8. Viruses are commonly referred to by their _________ name. A. locale B. genus C. disease D. species E. disease AND species

E. disease AND species

25. The enveloped viruses typically obtain their envelope A. from the host plasma membrane. B. as they exit the host. C. from a newly constructed viral-derived membrane. D. from the nuclear membrane. E. from the host plasma membrane AND as they exit the host.

E. from the host plasma membrane AND as they exit the host.

16. The receptors to which animal virus attachment proteins usually bind are A. proteins. B. carbohydrates. C. nucleic acid. D. lipids. E. glycoproteins.

E. glycoproteins.

30. The best-known examples of viruses that cause latent infections are A. polio. B. herpes. C. measles. D. chickenpox. E. herpes AND chickenpox.

E. herpes AND chickenpox.

34. Cells taken from a tumor A. may be used to grow viruses. B. can be cultivated in vitro indefinitely. C. may be used to grow bacteriophages. D. divide 50 times and then die. E. may be used to grow viruses AND can be cultivated in vitro indefinitely.

E. may be used to grow viruses AND can be cultivated in vitro indefinitely.

26. Carriers A. may have a persistent infection. B. may be a source of infection. C. usually show symptoms of the disease. D. have been cured of the infection. E. may have a persistent infection AND may be a source of infection.

E. may have a persistent infection AND may be a source of infection.

14. The lack of immunity to particular viruses appears to have resulted in epidemics, with dire consequences, of diseases such as A. hepatitis. B. polio. C. measles. D. smallpox. E. measles AND smallpox.

E. measles AND smallpox.

24. In the region of budding, the plasma membrane becomes involved with A. carbohydrates. B. spike proteins. C. matrix proteins. D. enzymes. E. spike proteins AND matrix proteins.

E. spike proteins AND matrix proteins.