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12 Cards in this Set
- Front
- Back
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What is a virus? |
An intracellular parasite made up of DNA or RNA surrounded by a capsid. |
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What is a capsid? |
the protein coat that surrounds the genetic material of a virus |
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What are the 2 (3) functions of the capsid of a virus? |
1) protects the nucleic acid genome during transit of virus from one cell to another 2) helps facilitate entry into host cell 3) In some cases, packages enzymes necessary for the early steps of the infection process |
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What are capsomeres? |
The many repeating, identical subunits that make up the capsid. If you visualize a virus as a cube, each face of the cube would be a capsomere. |
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What are capsomeres made of? |
Capsomeres are made of 5-6 individual protein molecules that are individually called Protomers. Each protomer may be similar to the other or may be a different protein. -If you visualize the virus as a cube, each face of the cube would be a capsomere and each point on the corners of the capsomere/faces would be a protomer. |
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What is a virion? |
The extracellular, inert form of a virus that is not in the process of infecting anything. |
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What are viruses that infect bacteria called? |
Bacteriophages (or simply, phages) |
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What are the 2 things a virus must do in order to replicate? |
1) Infect/deliver their genome into a host cell 2) Exploit the host machinery (ribosomes, host enzymes, etc) to produce new virions that can exit the cell to go and infect other cells. -In short, the replicative process of a virus is completely dependent on the host cell |
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What are the 2 processes by which a newly synthesized virus can exit its host cell? |
1) lysis of the host cell 2) budding |
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What is a nucleocapsid composed of? |
The genome of a virus together with its protein capsid. |
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What is the difference between an Enveloped virus and an Unenveloped virus? |
-Unenveloped viruses ("naked" viruses) simply have a nucleic acid genome surrounded by a protein capsid. -Enveloped viruses have an additional covering made of lipids that surrounds the protein capsid |
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True or false: the lipid covering on enveloped viruses is very similar in structure to the membrane seen in cell membranes. |
TRUE, in fact, this covering is usually acquired by the virus from the cytoplasmic membrane of the host as the virus exits the host cell. |
