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?
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?
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.
Persistent viral infections such as (a) ________ might be caused by (b) ________ that are (c) ________.
Plant viruses can’t penetrate intact plant cells because (a) ________; therefore, they enter cells by (b) ________. Plant viruses can be cultured in (c) ________.
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
In an agglutination test, eight serial dilutions to determine antibody titer were set up: Tube 1 contained a 1:2 dilution; tube 2, a 1:4, and so on. If tube 5 is the last tube showing agglutination, what is the antibody titer?
a. 5
b. 1:5
c. 32
d. 1:32