Term
T/F
Replication efficiency varies from a few to thousands of infectious viruses produced per cell. |
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Definition
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Term
t/f
Virus replication is never compatible with cell survival but often results in cell death. |
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Definition
| F. sometimes is compatible |
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Term
| Explain how viruses with different kinds of genomes accomplish gene expression and the production of new genomes |
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Definition
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Term
A cell is not resistant to a virus if there is no receptor
for the virus on the cell surface |
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Definition
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Term
Some viruses enter the cell via receptor-mediated endocytosis.
dont need to worry about crossing endosome membrane |
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Definition
| F do need to cross endosomal membrane after endocytosis |
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Term
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Definition
may involv:
Cellular and viral proteases may participate
For icosahedral DNA viruses, final genome release occurs at the nuclear envelope
Matrix/tegument proteins may also be released to function in the infected cell |
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Term
where does RNA virus replication process occur?
what are the exception? |
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Definition
cytoplasm
influenza and retroviruses |
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Term
where dose DNA viruss genome replicate ?
where does nucloecapsid assembly occur? |
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Definition
nucle
exception pox and hep B |
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Term
| positive strand RNA viruss uses ______ as mRNA |
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Definition
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Term
negative strand RNA must use __________
which is located in ______virion |
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Definition
| Rna dependent polymerasei s used in the virion, makes both mRNA and new genome (replicase) |
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Term
| genome replication of positive strand RNA viruses |
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Definition
Mrna, makes replicase protein.
- replciase makes negative starnd.
-negative starnd is copied ot make new positve starnd genomes |
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Term
| genome replication of negative strand RNA viruses |
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Definition
use positve strand intermediate.
-b/c it has a transcriptase, makes postive strand copies of genome |
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Term
| what happens after positve strands are made from negative RNA strand in genome replication? |
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Definition
| post starnds are copies to make new negative strand genome. so they can be packaged |
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Term
| Exceptional RNA viruses that dont use regular postive/negative strand replication? |
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Definition
Uncoated influenza
-Double-stranded RNA viruses replicate their genomes using a virion transcriptase/replicase that
-Retroviruses have a virion enzyme system that makes a double stranded DNA copy of the RNA genome
more details in lecture |
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Term
t/f
DNA viruses express genes in one phase |
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Definition
| phases, use temporal regulatory class, nad has early and late phases. |
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Term
what are the gene products used for during the
1. immediate early
2. early
3. late |
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Definition
1. control host regulatory genes
2. Genome replication
3. Virion assembly and packaging. |
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Term
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Definition
-Parvoviruses, polyomaviruses, and papillomaviruses
-hep B(similar to retrovirus
-pox:replicate completely in the cytoplasm and assemble in virus “factories”
Use own enzymes for all DNA and RNA synthesis |
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Term
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Definition
| using cell membrane to make envelope. |
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Term
| 3 other envelopment strategy besides budding |
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Definition
1. envelop in cytoplasmic membrane.
2. envelope in nuclear then cytoplasmic (herpes)
3. de novo via cytoplasmic fragment (POX) |
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Term
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Definition
| Cells that allow a complete viral life cycle including release of infectious virus are |
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Term
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Definition
| Cells that take up virus but do not allow the infection to be completed are |
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Term
T/F
all viruses kill infected cells |
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Definition
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Term
T/F
viral proteins can not inhibit host DNA, RAN and poretein synthesis |
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Definition
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Term
T/F
Viruses can disrupt cell membrane biosynthesis and structure |
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Definition
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Term
| Morphological changes that may occur (2 examples given) |
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Definition
1, polio:rounding monolayer damage
2. cytoplasmic eosinophil inclusion bodies |
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Term
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Definition
| Infection of non-permissive cells with no infectious virus production |
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Term
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Definition
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Term
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Definition
| no replication but some viral gene expression |
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Term
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Definition
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Term
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Definition
Oncogenic conversion caused directly by viral gene activities
Oncogenic conversion promoted by abnormal cell proliferation in tissues damaged by viral infection |
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Term
| How does the host fight back |
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Definition
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Term
| how does virus fight back |
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Definition
interferon inhibitors
anti-apototic proteins |
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Term
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Definition
Most RNA viruses replicate in the cytoplasm
The genome of positive strand viruses can be translated directly
The genome of negative strand viruses must be copied by a virion enzyme to make mRNA to initiate viral gene expression
The key component of replication intermediates is the strand with polarity opposite that of the genome that serves as a template for new genome synthesis |
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Term
| lecture sum 2 highightedd |
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Definition
Many viruses are cytocidal (kill cells)
Cytopathologies are characteristic of viral infection
-Intracellular host defenses must face virus gene products that have evolved to evade these defenses |
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