9/11/13 Flashcards
What is an exception to the rule that viruses contain either RNA or DNA
Poxvirus has both
What is an exception to the rule that viruses are smaller than bacteria
Mimivirus
This virus can cause disease in diverse species, which is an exception to the virus rules
Influenza A
Type of virus that is resistant to detergent ans solvent based disinfectants
Naked virus
Where does the envelope come from for enveloped viruses?
From the host plasma membrane or vesicles
What are the three shapes for viruses?
Icosahedral, helical, plemorphic
Viral entry in to a cell is always mediated by
receptors that are essential to the cell
Naked viruses enter the cell via this process
endocytosis
Naked viruses leave the cell by which process
cell lysis
Enveloped viruses leave the cell by which process
budding
How do enveloped viruses enter the cell?
Fusion with the plasma membrane or vesicles which then releases the capsids
Newly released viruses sometimes require steps for maturation, which almost always involves this
final protein cleavage
An area of the cell monolayer in tissue culture that is devoid of cells because a virus has killed them
viral plaques
This requires a conformational change in the capsid
uncoating
What are the two ways that a virus can change the conformation of its capsid for uncoatin
- Low pH
2. docking of the virus to specific cellular protein
What are the two virus specific nucleic acid polymerases
RNA dependent DNA polymerase, RNA dependent RNA polymerase
What are the stages for DNA virus gene expression
Immediate early, early (viral DdDp), and late (structural proteins for virions)
Where do DNA viruses generally replicate, and what is the exception to this rule
nucleus, Poxvirus
Which type of virus tricks the ribosome into translating the viral genes
+ss RNA
This type of virus requires RdRp to be packaged with it
-ssRNA
Where do RNA viruses generally replicate, and what are the exception to this rule
Cytoplasm, Orthomyxoviruses and retroviruses
What sequences in the viral genome enables the transcription of viral DNA during retrovirus replication
Long terminal receptors
The use of both strands to code genes in double stranded genomes, splicing mRNA in multiple ways, using different reading frames of the same DNA, using helper virus are strategies used by viruses to do what?
Genome maximization
