Biology (Mader), 10th Edition

Chapter 33: Lymph Transport and Immunity

Antiviral Activity of Interferon

Why is it difficult to defend against viruses? Viral diseases can be very difficult to treat. Unlike bacteria, viruses have no metabolism to disrupt. The immune system can often identify whole viruses and destroy them. Once the virus has introduced DNA or RNA into a host cell, disruption of the viral life cycle is much more difficult. To a large extent, the replication of viruses is carried out by the cellular machinery of their hosts. Disrupting the duplication of viruses would often mean damaging the ability of the host to carry on its normal functions. Interferon and other antiviral drugs exploit portions of viral life cycles that are distinct from the host and prevent viruses from taking hold in cells. In effect, they are superficially equivalent to a vaccine against viruses at the level of individual cells.

View the animation below, then complete the quiz to test your knowledge of the concept.



1.

When interferon attaches to a cell
A)virus can not enter the cell
B)virus can enter the cell but can not replicate
C)virus can replicate within a cell but can not be released
D)viral replication takes place as usual
2.

When interferon from one cell attaches to a second cell
A)the recipient cell makes enzymes that prevent cell metabolism
B)the second cell now makes interferon and saves itself
C)the recipient cell is able to kill bacteria
D)the recipient cell makes enzymes that degrade mRNA and prevent viral protein synthesis
3.

Interferon
A)is produced as a specific response to a specific virus
B)is produced by one cell and used to warn nearby cells of the same type
C)is able to save the cell that makes it
D)induces production of mRNA in the recipient cell
E)kills all bacteria nonspecifically
4.

Interferon degrades mRNA and prevents synthesis of viral protein.
A)True
B)False
5.

Interferon is produced by an animal cell that is infected by a bacterium.
A)True
B)False
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