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30 Cards in this Set
- Front
- Back
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Classified by ____________________ or by type of ________________________
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host range, nucleic acid
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Host-range barrier: _____________________ a virus infects is (usually) narrow and specific
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type of organism
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Host range barrier:
Determined by receptors on both _________________ and ___________ cells |
host, viral
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bacterial viruses=_______
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bacteriophage
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Viral envelope is made of
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carbohydrate, lipids, protein
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The three types of viral shapes are
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polyhedral, helical, and complex
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- binding of virus to specific molecules on host cell
– capsid/genome enters host cell – the viral nucleic acid is released from the capsid – viral components are produced – new viral particles are constructed – assembled viruses are released |
Adsorption
Penetration Uncoating Synthesis Assembly Release Budding or lysis |
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Name the two surface proteins of the influenza virus
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Hemagglutinin (HA):
Neuraminidase (NA): |
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RNA viruses generally are replicated and assembled in the cytoplasm.
-RNA contain the message for translation. -RNA must be converted into positive-sense message. |
Positive sense
Negative Sense |
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Function of Hemagglutinin (HA)
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binds to sialic acid receptors on host cells
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Function of Neuraminidase (NA):
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assists in release of virions
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The influenza virus has a ____ genome
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RNA
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Antigenic drift
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Mutations in H or N
Avoid antibodies Frequent but minor changes RNA genetic material has higher mutational rate |
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Antigenic shift
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Occurs infrequently
Change H or N protein gene Recombination animal/human genome segment Many mammalian strains—avian, porcine, human Pig serves as mutual host |
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Most common influenza type
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A
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Which influenza type affects avians?
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Type A
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Give two examples of persistant infections
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Measels, herpes simplex
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Latent vs persistant viral infections
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Latent viral infections
Virus remains in asymptomatic host cell for long periods Periods of outbreaks Persistent viral infections Disease process occurs over a long period generally fatal Cervical cancer (HPV) |
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Give 4 examples of oncoviruses
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Cervical cancer: Human papilloma virus (HPV)
HTLV-I and –II HHV-4 (Epstein-Barr): Burkitt’s lymphoma, nasopharyngeal cancinoma HHV-8: Kaposi’s sarcoma |
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Give 4 oncogenic changes
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Increase rate of cell growth
Loss of contact inhibition Chromosomal alterations such as change in number or breakage Changes to surface molecules |
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Give the definition of transformation
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acquisition of properties distinct from uninfected (or non-cancerous) cells
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-Important disease of plants
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Viroids
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-Proteinaceous infectious particle
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Prion
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-Subviral particles that can propagate only in the presence of another virus
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Satellite virus
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Give three methods of detection for virus identification
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Cytopathic effects
Serological effects Detection of viral nucleic acids |
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Bacteriophage Life Cycles
Lytic cycle: |
Phage causes lysis and death of host cell
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Bacteriophage Life Cycles
Lysogenic cycle: |
Prophage DNA incorporated in host DNA
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Lytic Cycle of T-even Phage
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Attachment
attachment of host cell receptor site to tail fibers of phage Penetration injection of DNA into cell Biosynthesis new viral components synthesized Maturation viral components assembled into virions Release lysis of cell and release of virions |
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Give 3 examples of animal prior diseases
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BSE: “mad cow disease”
Scrapie Chronic wasting disease |
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Give 2 examples of human prion diseases
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Kuru: transmissible
Creutzfeldt-Jakob |
