Download Viruses Answer Sheet

Viruses Answer Sheet
Virus ~ A virus is a parasite. A virus is a small, NONLIVING particle consisting of a core of
hereditary material surrounded by a protein coat.
 Explain virus reproduction ~ A virus invades and then reproduces inside a living cell.
Viruses have a major potential to impact the living world because they quickly reproduce and
cause new infections, often damaging the organism
Vaccine ~ Made from damaged virus particles that can’t cause disease anymore. Made from
weakened or killed form of the virus and prevent individuals from contacting the disease.
 There are no antibiotic medications to cure viral diseases, but viral diseases can be
prevented by vaccines
Viruses are spread: 1). Through the air, and 2). By contact with the infected person
Other than vaccines, ways to prevent viruses from spreading: cover your mouth when you
cough or sneeze, wash your hands often, and use sanitizer gels.
Classification
 Describe how viruses are classified: By their shape, the kind of hereditary material they
have, the kind of organism they infect, and their method of reproduction
 Explain two methods of naming viruses: The disease they cause or where they were
first found
 Identify 4 viruses and explain how each received it’s name: Rabies: named for the
disease it causes in animals; Adenovirus: named because it infects the adenoid tissue;
Bacteriophage infects bacteria; Tobacco-mosaic virus affects tobacco plants
Host cell ~ The living cell used by a virus
 Active virus
i.
Explain what an active virus is: an active virus causes the host cell to make new
viruses immediately
ii.
Bacteriophage – the process of a virus being ingested into the cell.
iii. List and describe the 4 steps that an active virus takes to reproduce inside a
bacterial cell
1. Attach: A specific virus attaches to the surface of a specific bacterial cell
2. Invade:The hereditary material of the virus injects itself into the bacterial cell.
3. Copy:The viral hereditary material takes control of the bacterial cell and the cell
begins to make new virus particles
4. Release: The cell bursts open and hundreds of new virus particles are released.
The new virus particles go on to infect other cells.
 Latent virus
i.
Explain what it means when a virus may appear to “hide” inside the host after
the virus enters the cell, the viruses genetic material becomes part of the host
cell’s genetic material. It does not immediately make new viruses or destroy the
cell; it appears to “hide” inside the host cell for many years.
ii.
Describe the 6 steps that occur in the reproductive cycle of a latent virus
1. The hereditary material of a virus injects itself into the cell
2. Virus becomes part of the bacterial cell’s chromosome
3. The bacterial cell divides
4. The virus leaves the chromosome and becomes active
5. New viruses are made
6. The bacterial cell breaks open and releases the virus…destroying the host
bacterial cell
iii.
Give an example of a latent virus
Cold sore is an example. Once you get the virus, you always have the virus. At times
the symptoms may not show (latent) but may become active.
Gene therapy ~ experimental method for determining helpful ways to use viruses.
 Gene therapy involves substituting correctly coded heredity material for a cell’s
incorrect heredity material
Explaining the graph: Viruses cannot survive as well at high temperatures, and therefore a
fever helps kill them