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Problem 1
Why do we classify viruses as obligatory intracellular parasites?
Problem 2
List the four properties that define a virus. What is a virion?
Problem 3
Describe the four morphological classes of viruses, then diagram and give an example of each.
Problem 4
Label the principal events of attachment, biosynthesis, entry, and maturation of a + stranded RNA virus. Draw in uncoating.
Problem 5
Compare biosynthesis of a + stranded RNA and a - stranded RNA virus.
Problem 6
Some antibiotics activate phage genes. MRSA releasing Panton-Valentine leukocidin is a toxin that can cause a life-threatening disease. Why can such a disease develop following antibiotic treatment?
Problem 7
Recall from Chapter 1 that Koch's postulates are used to determine the etiology of a
disease. Why is it difficult to determine the etiology of
a. a viral infection, such as influenza?
b. cancer?
Problem 8
Persistent viral infections such as (a) ________ might be caused by (b) ________ that are (c) ________.
Problem 9
Plant viruses can’t penetrate intact plant cells because (a) ________; therefore, they enter cells by (b) ________. Plant viruses can be cultured in (c) ________.
Problem 10
Identify the viral family that infects skin, mucosa, and nerve cells; causes infections that can recur because of latency; and has polyhedral geometry.
Problem 1
Place the following in the most likely order for biosynthesis of a bacteriophage: (1) phage lysozyme; (2) mRNA; (3) DNA; (4) viral proteins; (5) DNA polymerase.
a. 5, 4, 3, 2, 1
b. 1, 2, 3, 4, 5
c. 5, 3, 4, 2, 1
d. 3, 5, 2, 4, 1
e. 2, 5, 3, 4, 1
Problem 2
The molecule serving as mRNA can be incorporated in the newly synthesized virus capsids of all of the following except
a. + strand RNA picornaviruses.
b. + strand RNA togaviruses.
c. - strand RNA rhabdoviruses.
d. double-stranded RNA reoviruses.
e. Rotavirus.
Problem 3
A virus with RNA-dependent RNA polymerase
a. synthesizes DNA from an RNA template.
b. synthesizes double-stranded RNA from an RNA template.
c. synthesizes double-stranded RNA from a DNA template.
d. transcribes mRNA from DNA.
e. none of the above
Problem 4
Which of the following would be the first step in the biosynthesis of a virus with reverse transcriptase?
a. A complementary strand of RNA must be synthesized.
b. Double-stranded RNA must be synthesized.
c. A complementary strand of DNA must be synthesized from an RNA template.
d. A complementary strand of DNA must be synthesized from a DNA template.
e. None of the above
Problem 5
An example of lysogeny in animals could be
a. slow viral infections.
b. latent viral infections.
c. T-even bacteriophages.
d. infections resulting in cell death.
e. none of the above
Problem 6
The ability of a virus to infect an organism is regulated by
a. the host species.
b. the type of cells.
c. the availability of an attachment site.
d. cell factors necessary for viral replication.
e. all of the above
Problem 7
Which of the following statements is false?
a. Viruses contain DNA or RNA.
b. The nucleic acid of a virus is surrounded by a protein coat.
c. Viruses multiply inside living cells using viral mRNA, tRNA, and ribosomes.
d. Viruses cause the synthesis of specialized infectious elements.
e. Viruses multiply inside living cells.
Problem 8
Place the following in the order in which they are found in a host cell: (1) capsid proteins;
(2) infective phage particles; (3) phage nucleic acid.
a. 1, 2, 3
b. 3, 2, 1
c. 2, 1,3
d. 3, 1, 2
e. 1, 3, 2
Problem 9
Which of the following does not initiate DNA synthesis?
a. A double-stranded DNA virus (Poxviridae)
b. A DNA virus with reverse transcriptase (Hepadnaviridae)
c. An RNA virus with reverse transcriptase (Retroviridae)
d. A single-stranded RNA virus (Togaviridae)
e. None of the above
Problem 10
A viral species is not defined on the basis of the disease symptoms it causes. The best example of this is
a. polio.
b. rabies.
c. hepatitis.
d. chickenpox and shingles.
e. measles.
