Exam Prep Viruses Chapter 16 4th Edition

Chapter 16

Viruses

True / False Questions

1. Viruses can infect plants and animals, but none known that infect bacteria.

True False

1. Many viruses are inhibited by antibiotics.

True False

Multiple Choice Questions

1. The host range of a virus is determined by
2. the type of genetic information the virus contains.
3. All of the answer choices are correct.
4. the shape of the virus.
5. specific receptors on cells it infects.
6. the particular life cycle of the virus.
7. A site in nature where a virus exists is its
8. capsid.
9. bacteriophage.
10. reservoir.
11. clade.
12. progenote.
13. Human influenza viruses are usually derived from influenza viruses that infect
14. horses and sheep.
15. cattle and water buffalo.
16. a variety of primates.
17. birds and pigs.
18. chimpanzees and gorillas.
19. Which of the following diseases is not caused by viruses?
20. smallpox
21. polio
22. warts
23. diabetes
24. influenza

Use the labeled arrows to answer questions related to these five viruses.

1. The virus structure indicated by the arrow labeled A is the
2. genetic material, DNA or RNA.
3. the bacteriophage.
4. the bacterial membrane.
5. the lipid-rich envelope.
6. the protein coat, or capsid.
7. The type of virus indicated by the arrow labeled B is a(n)
8. plant or animal virus.
9. plant virus.
10. bacteriophage.
11. animal virus.
12. plant virus or bacteriophage.
13. The virus structure indicated by the arrow labeled C is the
14. the bacteriophage.
15. genetic material, DNA or RNA.
16. the protein coat, or capsid.
17. the bacterial membrane.
18. the lipid-rich envelope.
19. Viruses are smaller than
20. human red blood cells.
21. All of the answer choices are correct.
22. single-celled eukaryotes.
23. plant cells.
24. bacterial cells.
25. The genetic information in viruses
26. is single-stranded DNA.
27. is single-stranded RNA.
28. can be DNA or RNA, and single- or double stranded.
29. is double-stranded RNA.
30. is double-stranded DNA.
31. A layer of membrane outside the protein coat of some viruses is called a(n)
32. capsomere.
33. capsid.
34. protein coat.
35. envelope.
36. plasmid.
37. Viruses that infect bacteria are
38. prions.
39. not known to exist.
40. composed of protein only.
41. bacteriophages.
42. also capable of causing disease in humans.
43. The shape of a virus is determined by its
44. envelope.
45. RNA.
46. DNA.
47. coat protein organization.
48. host.
49. The host range of a virus is
50. the geographical location in which the virus is found.
51. limited by availability of its needed nutritional resources.
52. always limited to one species.
53. the type of organisms or cells that a virus can infect.
54. the boundaries of the ecosystem in which it is found.
55. A viral species is found to infect host fishes in isolated mountain lakes. The host range is
56. the one or more infected species of fishes that exhibit the viral disease symptoms.
57. All of the answer choices are correct.
58. the specific sizes and shapes of the fish tissue cells that become infected by the viruses.
59. the mountainous area, in which the isolated lakes are found and mapped.
60. impossible to determine, because the isolated lakes don't allow tests for the infection of other fishes.
61. The correct sequence of the stages of viral replication is
62. attachment, penetration, assembly, synthesis, and then release.
63. penetration, attachment, synthesis, release, and then assembly.
64. attachment, penetration, synthesis, assembly, and then release.
65. attachment, synthesis, penetration, assembly, and then release.
66. penetration, attachment, assembly, synthesis, and then release.
67. The stage of viral replication in which viral nucleic acids and proteins are manufactured is
68. synthesis.
69. attachment.
70. release.
71. assembly.
72. penetration.
73. The stage of viral replication in which the virus binds a cell surface receptor is
74. release.
75. attachment.
76. assembly.
77. penetration.
78. synthesis.
79. The stage of viral replication in which the new viruses leave the host cell is
80. synthesis.
81. attachment.
82. penetration.
83. assembly.
84. release.
85. The type of viral infection in which a virus enters a host cell, immediately replicates, and causes the host cell to burst is a infection.
86. systematic
87. transgenic
88. lytic
89. lysogenic
90. rare form of viral
91. Treating a bacterial infection by inoculating the host with a bacterial virus is
92. None of the answer choices is correct.
93. radiation therapy.
94. phage therapy.
95. antibiotic therapy.
96. chemotherapy.

23. Viral DNA inserted into a chromosome of the host is a

1. phage.
2. reservoir.
3. progenote.
4. carrier.
5. prophage.
6. Human immunodeficiency virus (HIV) is classified as
7. a retrovirus.
8. a liver carcinogen.
9. a skin-touch transmissable virus.
10. responsive to antibiotics.
11. a general mammalian infectious virus.
12. The enzyme that HIV uses to copy its RNA into DNA is
13. RNA integrase.
14. transcriptase.
15. reverse transcriptase.
16. DNA polymerase.
17. RNA polymerase.
18. A patient receiving a protease inhibitor and AZT is probably being treated for an infection by a
19. retrovirus.
20. protozoan.
21. DNA virus.
22. bacterium.
23. fungus.
24. Our most effective weapon against viral infections is
25. vaccinations.
26. antibiotics.
27. sulfa drugs.
28. surgery.
29. gene therapy.
30. Tobacco mosaic virus is most commonly introduced into plants through small wounds caused by handling and by insects chewing on plant parts. What would prevent most viruses from easily entering plant cells?
31. the cell wall of the plant
32. the plasma membrane of the virus
33. the protein coat of the virus
34. the cell wall of the virus
35. the plasma membrane of the plant
36. An infectious RNA molecule is a
37. virion.
38. bacteriophage.
39. virus.
40. prion.
41. viroid.
42. An infectious protein is a
43. prion.
44. prophage.
45. viroid.
46. virus.
47. virion.
48. A reason given by scientists as to why viruses are not considered living organisms is that
49. viruses can be frozen and still survive.
50. viruses do not reproduce on their own.
51. viruses are all smaller than the smallest known cells.
52. viruses do not contain a nucleus.
53. viruses do not contain genetic information.
54. Viruses are not considered as alive, yet they share with living cells the ability to
55. evolve.
56. respond to stimuli.
57. metabolize food.
58. reproduce on their own.
59. produce cell membranes.
60. Hepatitis A and C contain an RNA genome, whereas hepatitis B contains a DNA genome. What is the most plausible conclusion you could draw about these strains of hepatitis?
61. They do not all share a common ancestor.
62. They all have the same rate of occurrence.
63. They all have the same symptoms.
64. They do not all affect the liver.
65. They all have the same mode of transmission.
66. Oral infections with herpes simplex virus 1 can lie dormant in nerve cells for years. When a patient becomes stressed, the virus enters the active stage and forms cold sores on the lips. When the virus is inactive, or dormant, it is in the stage.
67. latent
68. symptomatic
69. lytic
70. infective
71. replicative
72. The influenza virus contains an RNA genome. Every year a flu vaccine is designed to protect against three different strains of the influenza virus. Why do scientists make a new vaccine each year?
73. The virus develops resistance to the vaccine.
74. People change their habits each year and become susceptible to different strains of the virus.
75. The virus can rapidly mutate into new strains.
76. The common influenza virus can come from many species of animals, including cats and dogs.
77. Our bodies develop resistance to the vaccine and it becomes less effective.
78. Smallpox is an enveloped virus with a DNA genome. We have eliminated this once deadly virus through an aggressive worldwide vaccination program. Why might a vaccine be successful with smallpox, but not with HIV?
79. DNA genomes mutate less rapidly than RNA genomes.
80. Host cells have RNA in them, and thus do not raise antibodies against RNA.
81. RNA is more stable than DNA, and is less likely to be destroyed by the vaccine.
82. Viruses with DNA genomes must replicate inside a host cell.
83. Smallpox is an enveloped virus.

37. Rhinovirus is an RNA virus that causes the common cold and sinus infections. The virus does not contain an envelope. Which of the following is true of a rhinovirus?

1. It does not contain genetic material.
2. It does not contain protein.
3. It does not contain lipid.
4. It does not contain protein or genetic material.
5. It does not contain lipid or protein.
6. Poliomyelitis is an RNA virus that can invade the nervous system and cause paralysis within a matter of hours. The nearly complete elimination of polio worldwide is due to
7. antibiotics.
8. improved water quality.
9. vaccination.
10. quarantine.
11. mosquito control.
12. Viruses always lack which of the following?
13. organelles
14. an envelope
15. a protein coat
16. genetic material
17. None of the answer choices is correct.
18. What is the genetic material found in HIV?
19. RNA
20. protein
21. carbohydrate
22. lipid
23. DNA
24. In studies designed to determine the origin of HIV, how did the researchers first know that Marilyn the chimp may be infected with HIV?
25. She had been used in HIV research.
26. She had tested positive for antibodies against HIV.
27. She had HIV DNA in her tissues.
28. She had symptoms of HIV infection, or AIDS.
29. She had HIV RNA in her blood.

1. Based on the figure, which of the following is true of HIV?
2. It uses reverse transcriptase from the cell to make DNA.
3. It replicates in the nucleus of cells.
4. It contains DNA as its genetic material.
5. It is an enveloped virus.
6. It lyses cells when it is released.
7. The human immunodeficiency virus (HIV) only affects a specific class of cells in the immune system called helper T cells, and not other types of T cells. Which is the best explanation for this observation?
8. Only helper T cells have the correct receptor on their cell surface.
9. HIV can only be released from helper T cells.
10. Only helper T cells have reverse transcriptase.
11. HIV can only replicate inside of helper T cells.
12. The helper T cells are not necessary for the immune system to fight viral infections.
13. Based on the figure from the section on HIV replication, why could researchers use PCR to amplify viral DNA from the chimp Marilyn's tissues?
14. PCR can amplify any genetic material.
15. HIV uses DNA as its genetic material.
16. PCR uses a reverse transcriptase and can thus detect RNA.
17. HIV is converted to DNA and integrated into a cell's chromosome.
18. Some of the HIV will be stuck to the outside of a cell.

1. SIV causes symptomless infections in monkeys and apes, yet causes AIDS-like disease in chimpanzees. HIV is closely related to SIV and causes AIDS in humans. Which of the following is the best explanation for these observations?
2. The effects of viruses on different species is random.
3. Chimpanzees and humans have a more recent common ancestor.
4. SIV is most likely latent in chimpanzees.
5. Monkeys, apes, and chimpanzees are all genetically very similar.
6. SIV is most likely lytic in apes and monkeys.
7. Based on the figure, which of the following statements is most likely accurate?
8. HIV arose more than once.
9. HIV and SIV are not genetically related.
10. The SIV strains will all have more sequence similarity with each other than with any of the HIV groups.
11. SIV only arose once.
12. HIV groups M, N, and O will be more similar to each other than to SIV.
13. Why has it been difficult to generate drugs to treat AIDS?
14. HIV mutates rapidly among infected humans.
15. People with HIV infections die very rapidly, before the drugs have a chance to cure them.
16. HIV does not cause AIDS.
17. HIV does not use any enzymes that can be targeted by drugs.
18. The only way to kill a virus is with a vaccine, not with drugs.
19. If a person is treated with a single anti-HIV drug, they often end up with a resistant strain. How does this occur?
20. The HIV wants to avoid the drug, so it becomes resistant.
21. The drug causes mutations in the HIV, making them resistant to the drug.
22. All of the answer choices are correct.
23. The drugs kill all sensitive viruses, leaving only the preexisting resistant viruses.
24. The drugs weaken the immune system, making a patient more susceptible to infection with resistant strains of HIV.
25. The structure of the anti-HIV drug azidothymidine (AZT) includes a phosphate group, a sugar group, and a nitrogen base, in the form of a nucleotide. Given its structure, how do you think it blocks viral replication?
26. It inhibits host T cells from replicating.
27. It blocks RNA synthesis by an enzyme.
28. It prevents HIV from entering the cell.
29. It blocks host cell DNA synthesis by an enzyme.
30. It inhibits the assembly of new viruses in the cell.
31. Drugs like aziodothymidine (AZT) work against HIV infections by inhibiting
32. the cleaving of proteins needed to make the protein coat of a virus.
33. host cells from reproducing.
34. viral DNA from inserting into the host chromosome.
35. viruses from entering a host cell.
36. reverse transcriptase.
37. What type of cell does HIV infect?
38. helper T cells
39. B cells
40. red blood cells
41. phagocytic cells
42. All of the answer choices are correct.