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31 Cards in this Set
- Front
- Back
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Do viruses have both DNA and RNA?
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No; contain a single type of nucleic acid, etither RNA or DNA
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What surrounds viruse's nucleic acid?
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protein coat
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What does it mean by obligatory intracellular parasites?
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absolutely require living host cells
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Are viruses sensitive to interferon?
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yes
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Do viruses have ribosomes?
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no
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What do you call those viruses that infect bacteria?
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bacteriophages or phages
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Viruses range from ___ to ___ nm in length.
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20-1000nm
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What is a capsid?
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protein coat that protects the nucleic acid of a virus
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What do you call the carbohydrate-protein complex that project from the surface of the envelope?
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spikes
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What is a virion?
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a complete, fully developed, infectious viral particle complsed of nucleic acid and surrounded by a protein coat.
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what are nonenveloped viruses?
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viruses whose capsids are not covered by an envelope
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These viruses resemble long rods that may be ridid or flexible.
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helical viruses
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Name an example of helical viruses
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Ebola virus
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What is an icosahedron?
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a regular polyhedron with 20 triangular faces and 12 corners.
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Name an example of polyhedral viruses
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poliovirus, adenovirus
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name an example of an enveloped viruses
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herpes simplex viruses
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Name an example of a complex viruses
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bacteriophage
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what is hemagglutination?
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clumping of red bood cells; certain viruses clumping of red blood cells is associated with spikes
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What is a viral species?
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a group of viruses sharing the same genetic information and ecological niche (host range)
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What characteristics are used in grouping of viruses?
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1. nucleic acid type, 2. strategy for replication, 3. morphology
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What are plaques?
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clearing area visible against a lawn of bacterial growth on the surface of the agar media
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What do you use plaque method?
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used for detecting and counting viruses
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what do viruses need to do in order to multiply?
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must invade a host cell and take over the host's metabolic machinery.
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List 3 techniques to identify viruses
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restriction fragment length polymorphisms, PCR, western blotting, serological methods.
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what kind of microscope is used in observing viruses?
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electron miroscopes
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what is the major difference between lytic and lysogenic cycle?
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lytic cycle ends with lysis of the host cell; lysogenic cycle host cell remains alive.
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What are five distinct stages of viral multiplication cycle?
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attachment, penetration, biosynthesis, maturation, release
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bacteriophage lambda uses what kind of multiplication cycle?
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lysogenic
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What is prophage?
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inserted phage DNA into bacterial chromosome by recombination
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what is pinocytosis?
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active cellular process by which nutrients and other molecules are brought into a cell.
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enveloped viruses can enter the host cell by an alternative method called?
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fusion; fuses with plasma membrane
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