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39 Cards in this Set
- Front
- Back
Viruses must be grown in what?
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Living cells
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What is the easiest type of virus to grow?
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Bacteriophage (complex virus)
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What method is used to count viruses on a solid medium?
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Plaque method
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What is the area of lysis within the solid medium called?
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Plaque
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What is a single plaque area called?
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Plaque-forming units (PFUs)
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Cultivation of some animal viruses requires what?
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Whole animals (mice, rabbits, guinea pigs, etc)
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Besides whole animals, what is another thing that is used to cultivate animal viruses?
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Chicken embryos (eggs)
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What is used to cultivate many vaccines like the Flu vaccine?
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Chicken embryos (eggs)
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What is the most common method of growing viruses today?
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Cell cultures
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What are 3 ways of cultivating viruses?
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1. Whole animals
2. Chicken embryos (eggs) 3. Cell cultures |
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What are 2 ways of identifying viruses?
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1. Serological test
2. Nucleic acid finger prints |
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Which test is used more often to identify viruses?
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Serological test
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Do viruses contain enzymes?
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No, viruses do not contain enzymes for energy production or protein synthesis
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True or False:
Some viruses are capable of protein synthesis |
False - No viruses are capable of protein synthesis
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In order for viruses to multiply, what must it do?
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Invade a host cell and redirect the hosts METABOLIC MACHINERY to produce viral enzymes and components.
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What are 2 types of reproduction that viruses exhibit?
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1. Lytic cycle
2. Lysogenic cycle |
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What happens during the lytic cycle?
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Phage causes the lysis and death of a host cell; virus injects nucleic acids within host, creates components, replicates, and lysis
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What happens during Lysogenic cycle?
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Phage injects nucleic acids within host and the acids are incorporated within the DNA (prophage) of the host.
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What is a prophage?
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When the viral nucleic acids combine with the host DNA.
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What is lysogeny?
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Infected host cell that contain prophages (inactive).
**prophages are viral nucleic acids that are incorporated into the host cell DNA |
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What can potentially be initiated to lysogenous cells?
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Lytic cycle
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What 2 components or factors can lead to the excision of the prophage and initiate the lytic cycle?
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1. Mutagens
2. Spontaneous events (recombination) |
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A lysogenic host cell can transfer bacterial genes through what?
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Transduction
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Besides the inevitable lytic cycle of lysogenic host cells, phage genes also assist in what for bacteria?
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Virulence
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What is "burst time"?
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Time from phage absorption to release (20 to 40 min).
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How long can burst time take?
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20 to 40 min
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What is "burst size"?
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The number of newly synthesized phages produced from a single infected cell (50 to 200 or more viral particles).
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How many phages can be produced during burst size?
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(50 to 200+)
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What bacteria is found on meat and poultry products that infected 2,500 people (500 deaths)?
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Listeria monocytogenes
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What is used to kill of Listeria monocytogenes within meat and poultry products?
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6 types of bacteriophages
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What is seen on meat and poultry packages when it has been treated with viral food additives to kill of Listeria monocytogenes?
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"Bacteriophage Preparation"
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What are animal viruses called?
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Retrovirus
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What is the family that Retroviruses belong to?
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Retroviridae
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What type of viruses are Retroviruses?
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Enveloped viruses with RNA genome
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When a Retrovirus enters an animal host cell and uncoats the nucleic components, what happens next?
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The "reverse transcriptase" performs reverse transcription from RNA to double helix DNA
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When a Retrovirus performs reverse transcription within the animal host cell, what happens next?
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Viral ds/ss DNA is incorporated into the host DNA with the help of the integrase enzyme
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What enzyme is used to help integrate viral DNA into host DNA?
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Integrase enzyme
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What enzyme from the Retrovirus is used within a host cell to perfrom revers transcription?
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Reverse transcriptase
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What are the steps to animal replication?
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1. Attachment
2. Penetration via endocytosis (phagocytosis) 3. Uncoating of capsid 4. Viral genome replication (RNA to ds/ss DNA) 5. Synthesis of both DNA 6. Release of viruses (lysis or budding) |