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VIROLOGY FINAL EXAM Questions with Correct Answer1.
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VIROLOGY FINAL EXAM Questions with CorrectAnswers
1. In the Ebola virus life cycle, viral protein 35 (VP35) and viral protein
24 (VP24) using a coordinated approach to "not only diminishes the
interferon alarm, but also inhibits the alarm response after it is heard."
How do VP35 and VP24 do this? Correct Answer-VP35 inhibition of a
and b interferon
VP35 disrupted the RIG-I pathway by preventing IRF-3 phosphorylation
(interferon signaling cascade)
inhibits PACT, RIG1, and MDA5
decreases interferon production and stops PACT from slowing
transcription in antiviral state
VP24 STAT-1 pathway = antiviral state
VP24 binds to karyopherin STAT-1 being blocked no gene expression
VP24 also binds to unphosphorylated STAT-1 no gene expression
ANTIGEN PRESENTATION AND INHIBITION OF INTERFERON
2. A. What are some of the factors that contribute to zoonotic spillover
from bats to humans? Correct Answer-habitat destruction, eaten by
people, many spp worldwide, can multiply intermediate host, climate
change expands their range, they shed viruses when stressed after
storms/pregnant, when pop increases, close contact, epidemic, pop
decreases, cycle begins. can spread to other species, volant- fly and drop
feces/urine, infect animals that humans are in contact with cattle and
horses. large range
,2. B. Name four viruses from which humans suffer that are carried by
bats Correct Answer-SARS, Rabies, MERS, ebola
3. What does this figure above (Figure 3A) from the article by Vähä-
Koskela et al. show? And given this data and the other details from the
paper, does this mean that adeno-poxvirus combination therapy is killing
the cancer? Correct Answer-this figure shows that the control (saline
solution) does not decrease tumor burden. with adenovirus or vaccinia
virus alone, there was decrease in tumor burden, but the highest decrease
was seen with a combination of adenovirus and vaccinia virus therapy,
meaning yes this combo does kill cancer
4. A. What three enzyme activities are necessary for retrovirus
integration into the host genome? Correct Answer-Reverse
Transcriptase- enzyme used to generate complementary DNA (cDNA)
from an RNA template, a process termed reverse transcription
Protease- as virus leaves cell- cleavage of proteins- cleaves at Gag and
Gag-pol precursors
Integrase-
4. B. Where does integration preferentially occur? Correct Answer-IN
THE NUCLEUS? IN WHICH GENE? Integration preferentially occurs
in active genes. Being incorporated into active genes allows for the viral
genome to be expressed. Therefore, it allows the integrated DNA to
create more viruses which can then infect more cells, and spread the
virus.
, 4. C. Why is the site of integration important for retrovirus replication?
Correct Answer-if it is integrated in a gene that is not often replicated, it
is limited to the gene where it is integrated... if it integrates in
heterochromatin, that isn't transcribed so it wouldn't be replicated
4. D. What are the reasons why HIV has 2 copies of +RNA in its
genome? Correct Answer-~it needs both copies to reverse transcribe
~very high mutation rate in retroviruses- 2 copies better insures viability
4. E. How does the method of cell entry of HIV differ from that of
Influenza A? Correct Answer-HIV binds, surface and transmembrane
proteins bind to the CD4 receptor/co-receptor. NEEDS 2 RECEPTORS
viral and cell envelopes fuse, viral core is deposited into cytoplasm
Flu A binds to sialic acid receptor- globular heads of HA bind, receptor
complex is endocytosed (fueses with membrane and entire endosome
enters), acidification of the endosome causes conformational change,
genome is released
low ph trigger
4. F. How is the behavior of hemagglutinin similar to that of the HIV
envelope protein? Correct Answer-Influenza's HA proteins and HIV's
surface and transmembrane proteins are both recognized by a receptor.
because they both mutatate rapidly, the receptor can switch BOTH
HAVE FUSION PROTEINS
5. A. Viruses, such as Vaccinia virus have been demonstrated to infect
other cells at rates that are faster than regular kinetics. Using what was
learned from Doceul et al, how is this possible? Correct Answer-the
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