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23 Cards in this Set
- Front
- Back
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What is a capsomere?
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this is the small protein subunits, usually made of small proteins themselves, that then collect into groups to form a capsid
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what is a capsid?
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this is the protein covering surrounding a core of nucleic acids (and maybe some enzymes)
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What is the principle structural feature of viruses?
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proteins
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What are the two main proteins that have enzymatic functions, that viruses carry themselves?
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RNA dependent RNA polymerases
Reverse transcriptase for retroviruses |
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where are these enzymatic proteins in viruses located?
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usually they are part of the capsid
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What is a virion?
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this is the complete infectious virus particle
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what is an envelope? what makes it up?
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this is a membrane like outer covering of certain viruses.
this is made up of host membrane with some virus proteins |
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What are the spikes (peplomeres)
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these are virus proteins embedded in the envelope that project from the surface, often have enzymatic activities
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What is the processing for Negative (-) strand RNA viruses?
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they must first use viral RNA dependent RNA polymerase to create a positive + strand
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What is the central goal of all viruses?
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the replicate the virus at the expense of the host cell
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What are the 3 stages of animal cell virus replication?
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Attachment
a Latent Period burst or release of progeny virions (can either lyse the cell, or bud out over time) |
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What are the 5 stages of animal cell virus replication?
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attachment- to receptors @ cell surface, determines specificity
Penetration Uncoating Synthesis Maturation/Release |
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What are the 3 methods of penetration for viruses?
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Surface eclipse - direct fusion w/ membrane
membrane/membrane fusion (viral membrane gets added to host) Receptor-mediated endocytosis (Viroplexis) |
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Who directs the uncoating process?
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this is done by host cells that remove the capsid
(except for poxviruses!!) |
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What are the early and late genes used in virus synthesis?
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early- DNA synthesis
Late- Capsid proteins (virus builds itself from inside out) |
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What are the two methods of virus maturation/ release?
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Burst or budding
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Where does DNA virus replication and maturation occur?
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In the host nucleus
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What do viruses do to non dividing cells to ensure they will replicate their viral DNA?
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they disrupt p53 and Rb functions to push the host cell into S phase.
(SOME viruses are host independent for DNA replication, like POX) |
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Where does RNA virus replication and maturation occur?
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in host cell cytoplasm
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Whats the main problem with RNA viruses?
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RNA is unstable and must be replicated fast in cells
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What is the hallmark of retroviruses?
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reverse transcription and integration
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What is the synthesis order for retroviruses?
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RNA (ds)-> DNA (ss integrated into the host genome as provirus)-> RNA
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What four viruses have strong risk factors for cancers?
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HPV (16/18- oral/cervical cancer)
EBV (Burkitts lymphoma, nose cancer) Hep B/C (liver cancer) Herpies type 8 (kaposi's sarcoma) |
