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Campbell Biology

Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson

Chapter 19

Viruses - all with Video Answers

Educators

Chapter Questions

04:47

Problem 1

Which of the following characteristics, structures, or processes is common to both bacteria and viruses?
a. metabolism
b. ribosomes
c. genetic material composed of nucleic acid
d. cell division

Hiram Johnson
Hiram Johnson
Numerade Educator
03:32

Problem 2

Emerging viruses arise by
a. mutation of existing viruses.
b. the spread of existing viruses to new host species.
c. the spread of existing viruses more widely within their host species.
d. ail of the above.

Hiram Johnson
Hiram Johnson
Numerade Educator
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Problem 3

To cause a human pandemic, the H5N1 avian flu virus would have to
a. spread to primates such as chimpanzees.
b. develop into a virus with a different host range.
c. become capable of human-to-human transmission.
d. become much more pathogenic.

Xiao Zi Huang
Xiao Zi Huang
Numerade Educator
02:18

Problem 4

A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and $\mathrm{T} 4$ phage DNA. The new phages produced would have
a. T2 protein and T4 DNA.
b. T2 protein and T2 DNA.
c. T4 protein and T4 DNA.
d. T4 protein and T2 DNA.

MR
Michael Richmond
Numerade Educator
03:14

Problem 5

RNA viruses require their own supply of certain enzymes because
a. host cells rapidly destroy the viruses.
b. host cells lack enzymes that can replicate the viral genome.
c. these enzymes translate viral mRNA into proteins.
d. these enzymes penetrate host cell membranes.

Laura Anderson
Laura Anderson
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06:47

Problem 6

Redraw Figure 19.7 to show the replicative cycle of a virus with a single-stranded genome that can function as mRNA (a class IV virus).

Leah Lampen
Leah Lampen
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05:46

Problem 7

The success of some viruses lies in their ability to evolve rapidly within the host. Such a virus evades the host's defenses by mutating and producing many altered progeny viruses before the body can mount an attack. Thus, the viruses present late in infection differ from those that initially infected the body. Discuss this as an example of evolution in microcosm. Which viral lineages tend to predominate?

Leah Lampen
Leah Lampen
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01:48

Problem 8

When bacteria infect an animal, the number of bacteria in the body increases in an exponential fashion (graph A). After infection by a virulent animal virus with a lytic replicative cycle, there is no evidence of infection for a while. Then the number of viruses rises suddenly and subsequently increases in a series of steps (graph B). Explain the difference in the curves.

Alexander Cheng
Alexander Cheng
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02:11

Problem 9

While viruses are considered by most scientists to be nonliving, they do show some characteristics of life, including the correlation of structure and function. In a short essay $(100-150$ words), discuss how the structure of a virus correlates with its function.

Prashant Bana
Prashant Bana
Numerade Educator
03:28

Problem 10

Oseltamivir (Tamiflu)-an antiviral drug prescribed for influenza-acts to inhibit the enzyme neuraminidase. Explain how this drug could prevent infection in someone exposed to the flu or could shorten the course of flu in an infected patient (the two reasons for which it is prescribed).

Hiram Johnson
Hiram Johnson
Numerade Educator