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25 Cards in this Set

  • Front
  • Back
Do RNA viruses use DNA intermediates at any point in their life cycle?
No, they strictly use RNA.
Name a type of RNA virus that makes one large mRNA that is post translationally modifed to make different products.
Name two examples of viruses that make multiple mRNAs that each make a different protein product.
1. Coronaviruses
2. Rhabdoviruses
How is an RNA virus different from a retrovirus or a DNA virus?
RNA viruses package their own polymerases and enzymes. They do not use the host's polymerases.
What type of genome does Picornavirus have?
(+) ssRNA RNA
What type of capsid does picornavirus have?
A protein only capsid - no lipids
What is essential in Polio virus that enables its mRNA to be recognized by human translational machinery?
750bp 5' UTR
What is the receptor for polio virus? Rhinovirus?
1. CD155
2. ICAM-1
Will antibodies binding to Rhinovirus interfere with ICAMs binding to it?
Why do Rhinoviruses mutate often?
Mistake prone RNA polymerase.
What are two proteases used by poliovirus to cleave the large protein made by translation of its genome? What is the name of the RNA dependent polymerase used to make new RNA copies?
1. 2A Protease
2. 3C Protease - clips in many places
3. 3D'
What is unique about these proteases?
They are contained within the large protein from translation of the RNA genome. They cleave from within the protein.
What must be done before the RNA genome of picornavirus can be replicated?
Since it is a (+) ssRNA virus, it must first replicate a (-) ssRNA that acts as the template for replication.
What is a structural difference between picornavirus and alphavirus?
Alpha virus contains transmembranse glycoproteins that stud the lipid bilayer and picornavirus is naked.
What is the big difference in the RNA polymerase function between Alphavirus and Picornavirus?
Alpha virus first makes a complimentary copy of the (+) RNA. The RNA polymerase takes the (-) RNA that was made and starts another round of replication internally. The result is a short (+) RNA that only contains codes for structural proteins.
How does Alphavirus aquire the lipid bilayer membrane during assembly?
It aquires it through the process of budding through the host lipid bilayer.
What is a big difference between Flavivirus and Alphavirus?
While Flavivirus does also have a lipid bilayer envelope with glycoprotein studs, it aquires its bilayer from the ER or the GA.
What is the cellular receptor for West Nile Virus?
Alpha-v beta-3 integrin - highly conserved across species
What extra protein does Flavivirus have and what does it do?
1. M protein
2. Facilitates interaction between the nucleocapsid and the lipid-bilayer envelope.
Where does Coronavirus do its budding? What other virus is this like?
It does its budding from the ER or the GA like Flavivirus.
What is unique about the process of making viral proteins in coronavirus?
Each viral mRNA is coded for one gene and they all have the same 3' end.
What is the cellular receptor for SARS (coronavirus)?
What type of genome does Rhabdovirus have?
(-) ssRNA
How is the transcription of the Rhabdovirus different than the transcription of the coronavirus?
There are separate mRNA for each gene product like coronavirus, but unlike coronavirus the mRNA are not co-terminal.
How does rhabdovirus aquire its lipid bilayer membrane?
Through budding at the cell membrane