Virus Research Guide
In your research you are expected to compare the structures of viruses to cells, describe viral
reproduction, and describe the roles of viruses in causing diseases such as human
immunodeficiency virus (HIV) and influenza.
Fundamental Questions
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What are the various types of viruses?
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How are viruses and cells similar?
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How are viruses different from cells?
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Why does a virus have to use a host cell to replicate?
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What are two ways that viruses can be replicated by host cells?
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How does a virus cause disease?
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What kinds of viruses are there?
Scope Vocabulary:
antibiotic, bacteriophage, capsid, chicken pox, genetic material, hepatitis C,
host, Human Immunodeficiency Virus (HIV), immunization, influenza, lysogenic
cycle, lytic cycle, measles, mumps, passive immunity, pathogen prion,
retrovirus, rubella, small pox, t-cell, toxin, vaccine, vector, virus
Key Concepts
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A virus is much smaller than a cell and consists of little more than a genome
surrounded by a protein coat; some viruses are enclosed in lipid envelopes. Like a
cell, a virus has a genome made of nucleic acids (DNA or RNA). All viral molecules
are synthesized by host cells and then coopted by the virus. A virus has specific
proteins on its outer surface that enable it to infect host cells. Viruses have neither
a cytoplasm nor any internal membrane-bound compartments or organelles.
Retroviruses have reverse transcriptase that allows them to transcribe their RNA
genomes into DNA.
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A virus is a non-living, obligate parasite that does not have its own metabolism,
lacks cellular structure, and is unable to synthesize new molecules or reproduce
outside of a host cell. A virus reproduces either by using the machinery of the host
cell to make copies of itself, which causes the host cell to burst (lytic cycle); or by
incorporating its genome into that of the host (lysogenic cycle).
•
Viruses infect cells and cause diseases like chicken pox, the common cold,
influenza, encephalitis, dengue fever, measles, small pox, and many more. The
disease symptoms depend, in part, on what type of cells the virus infects (blood
cells, nerve cells, respiratory cells, etc.). Some animal viruses can transform a
normal host cell into a cancerous one by incorporating their genomes into those of
the host in ways that disrupt the normal regulation of cellular growth. When a
virus infects a human, the immune system attempts to destroy it along with other
cells that are infected. The infected cells themselves often self-destruct, though
many viruses have mechanisms to block this defense mechanism. The powerful
host immune responses caused by viruses are actually responsible for many of the
disease symptoms.
•
Because viruses hide inside host cells, attempts to control virus infection usually
result in harm to the host. Treatments for virus infection include chemicals that
inhibit virus replication, like AZT which inhibits reverse transcriptase of the HIV
retrovirus that causes AIDS.
Virus Poster Guide
Your Poster will contain . . .
. . . a summary to describe the structure of a virus and how viral structures relate to the
structures of a cell.
. . . a graphic of the structure of a virus and how it compares to the structures of a cell.
. . . an explain of how viruses reproduce.
. . . a diagram that details the lytic and lysogenic cycles of viral reproduction.
. . . a summary describing how some diseases are caused by viruses.
ü The effect of HIV on the immune system.
ü Helper T-Cells
. . . an explanation of how vaccines help in preventing the spread of viruses while
antibiotics do not.