VIROLOGY EXAM 2 Flashcards
Highly pathogenic H5N1 influenza A viruses are currently under close surveillance worldwide due to unusual die-offs of wild birds and an alarming rise in mammalian infections, although direct human-to-human transmission has not yet been documented. You decide to contribute to pandemic preparedness by creating a new vaccine for these viruses, similar to the seasonal influenza virus vaccines currently produced in eggs.
H5N1 section question #1:
Which of the following viral genome segments would you select from the circulating H5N1 strain to combine with the “standard parts” of thecurrent seasonal influenza vaccine production system? (select all correct answers):
a) PB2
b) PB1
c) PA
d) HA
e) NP
f) NA
g) M
h) NS
d) HA
f) NA
H5N1 section question #2:
Your new H5N1 vaccine directly interferes with a key step in viral infection. Which one?
a) Attachment
b) Penetration
c) Uncoating
d) Transcription
e) Translation
f) Genome
g) Replication
h) Assembly
i) Release
a) Attachment
H5N1 section question #3:
Meanwhile, while ygur vaccine strain grows in the embryonated chicken eggs, you decide to test whether existing anti-influenza virus drugs are effective against these H5N1 viruses. You test an M2 inhibitor (amantadine), an NA inhibitor (oseltamivir) and an RdRp inhibitor (baloxivir). Please match the inhibitor with the anticipated outcome.
Uncoating failure
i. Amantadine
ii. Oseltamivir
iii. Baloxivir
Release failure
i. Amantadine
ii. Oseltamivir
iii. Baloxivir
Transcription failure
i. Amantadine
ii. Oseltamivir
iii. Baloxivir
Uncoating failure
i. Amantadine
Release failure
ii. Oseltamivir
Transcription failure
iii. Baloxivir
Which virus does NOT enter the cell by fusion of a viral envelope with cellular membranes?
a) influenza virus
b) coronavirus
c) poliovirus
d) herpesvirus
e) Zika virus
c) poliovirus
Pattern recognition receptors: (select all correct answers)
a) permit viruses to enter the cell
b) bind to foreign viral nucleic acids
c) initiate antiviral immune responses
d) cut up viral polyproteins into individual proteins
b) bind to foreign viral nucleic acids
c) initiate antiviral immune responses
Virus capsids are _________, which means that they are strong enough to withstand the environment and protect the genome, but can be ‘unlocked’ and disassemble during entry into a new host cell.
metastable
Bacteriophage T4 injects _________ into the E. coli periplasm to degrade peptidoglycan.
a) lipopolysaccharide
b) dsDNA
c) tail fibers
d) lysozyme
e) DdDp
d) lysozyme
Influenza virus _________ protein helps newly-assembled influenza virions escape from the cell surface by degrading sialic acid sugars.
a) matrix
b) neuraminidase
c) non-structural
d) hemagglutinin
b) neuraminidase
Viral enzymes can not be structural proteins.
a) True
b) False
b) False
A virus with an RNA-dependent DNA polymerase (RdDp):
a) synthesizes DNA from an RNA template
b) synthesizes RNA from an RNA template
c) synthesizes RNA from an DNA template
d) synthesizes DNA from a DNA template
a) synthesizes DNA from an RNA template
____________ describes the process whereby the metastable capsid disassembles to release the viral genome.
uncoating
You’re working on a new emerging virus called ‘VirusX. Your job is to investigate the viral replication cycle. Fortunately, you have some information about the virus. It replicates in human cells, and biochemical analysis revealed that it has an RNA genome. Using __________
[light, electron, fluorescence, X-ray ] microscopy, you observe that it has a ‘bullet-shaped’ morphology with distinctive spiky projections.
You hypothesize that the spiky projections are the _________ [nucleocapsid, matrix, VAP, enzyme ].
Treatment of viruses with detergent renders them non-infectious, suggesting _____________ [helical, complex, enveloped, icosahedral ] morphology. You decide to conduct some infection experiments and test available antiviral drugs to learn more about how the virus replicates.
Treatment of infected cells with an RdRp inhibitor blocked viral replication. However, even though replication was blocked, some viral proteins still accumulated to high levels in infected cells and you observed the formation of cytoplasmic ‘viral factories’. This tells you that the viral genome is _____________
[dsRNA, ssDNA, dsDNA, (+)ssRNA, (-)ssRNA ].
Further analysis of the genome
reveals that it is segmented, with 4 RNA segments total. You reason that each genome segment must have a
5’ ___________ [promoter, enhancer, cap, ribosomal frameshifting site, polyA tail] and a 3’ ____________
[promoter, enhancer, cap, ribosomal frameshifting site, polyA tail].
Your supervisor is so impressed with your work that they give you more. You start studying another emerging RNA virus called ‘VirusY: Treatment of VirusY infected cells with RdRp inhibitor also blocked viral replication, but this time, no viral proteins or RNA products accumulated in infected cells. This tells you that the viral genome is _________ [dsRNA, ssDNA, dsDNA, (+)ssRNA, (-)ssRNA], and that it must enter the cell with a structural ___________ [protease, RdRp,
RdDp, ribosome].
1) electron
2) VAP
3) enveloped
4) (+)ssRNA
5) cap
6) polyA tail
7) (-)ssRNA
8) RdDp
Viruses break the central dogma of molecular biology via (select all correct answers):
a) RdDp
b) RdRp
c) DdDp
d) DdRp
a) RdDp
b) RdRp
Which of the following contribute to influenza virus antigenic shift? (select all correct answers):
a) the segmented genome.
b) co-infection of a host animal with an avian strain and a human strain.
c) mRNA splicing
d) cleavage of polyproteins
e) evasion of neutralizing antibodies
a) the segmented genome.
b) co-infection of a host animal with an avian strain and a human strain.
e) evasion of neutralizing antibodies
During enveloped virus entry, a ___________ is inserted into the host cell membrane, which eventually leads to mixing of viral and host membranes.
a) fusion peptide
b) nucleoprotein
c) tegument protein
d) matrix protein
a) fusion peptide
