PCB4522 COVID-19 Extra Credit
3 days
how long does COVID-19 live on polypropylene plastic?
exoN (nsp 13)
which viral protein serves a proofreading function that protects the large genome of SARS-CoV from excessive mutations? (this protein has two activities. its other function is to add a 5'-cap to newly synthesized viral RNAs)
1
transmembrane domain that is embedded in viral envelop
false
true or false: one commonality between COVID-19 and a flu virus is that both of them must enter the nucleus to take control of the cell
nsp1
the ______ protein(s) binds the 40S ribosome of the host and cleaves the 5'-end of host mRNAs, which removes the CAP and results in their degradation. it does not cut the viral RNAs because the virus has methylated the CAP of its own RNAs to mark them as viral
S
the __________ protein attaches to the host ACE2 receptor and then promotes fusion of the host membrane with the envelop of the viral particle
16
the first viral protein that is expressed in the infected cell is actually a series of multiple proteins translated together as a polyprotein. the polyprotein is cleaved into functional proteins by a viral-encoded protease. question: how many proteins are derived from the original polyprotein?
1- this enables each of the coding regions to be translated, and 2-RNA recombination resulting from the "jump and copy" mechanism of the RdRP facilitates error correction by RNA recombination
what are two reasons that SARS-CoV uses subgenomic RNAs?
5
ACE2 receptor binding domain of the spike
2
ACE2 receptor on the outer surface of the human cell
true
S, E, M, and N are four structural proteins that are encoded by the subgenomic RNAs of the COVID-19 virus
2
cut site 1 (releases the top portion of the spike S1)
3
cut site 2 (releases the red region which activates the stem to unfold)
membrane (M) and spike (S) proteins
during replication of the virus, which structural protein encoded by the virus embeds itself into the host membranes of the ER and golgi complex and causes a region to bleb out to form the envelop of the viral particle?
8
fusion domain that becomes embedded into the host membrane when the stem unfolds
4
glycan sugar moieties that decorate the spike protein to hide it from the immune system
4
human protease that cuts at two sites within the spike protein to release the head portion (S1) and activate the unfolding of the stem
it dissolves the lipid membrane envelope of the virus
in order to get rid of the virus on your skin, why is soap important?
nsp1-16
in the genomic map below of SAR-COV-2, which proteins are translated from the original positive-strand RNA that is packaged in the viral particle?
7
region that is released by cut 2
1
spike portion of spike protein (S1)
3
stem portion of spike protein (S2)
6
stem region, which in this image is folded on itself
nsp11 and nsp12
the RNA dependent RNA polymerase and viral helicase are encoded by which of the following nonstructural proteins (nsp's)?
true
the RNA viruses like to attach to the ACE2 receptors in our cells, which are found in large amounts inside our lungs
true
the function of the nsp1 protein is slow down expression of host mRNAs so that viral RNAs are favored. it does this by binding to the 40S ribosome and then cutting the CAP off the host mRNAs as they arrive for translation
false
the only known tissue where the SARS-CoV-2 virus can replicate is in lung epithelial cells
true
the r-naught (Ro) value is not intrinsic to the virus, it depends on environmental conditions and the behavior of a culture or society
the nsp's encode enzymatic activities that prepare the way for replication processes which is an early step in the cycle. it makes sense that these proteins are synthesized first, because they are needed prior to assembly of the viral particle
what is the best evolutionary rationale for having the nsp's translated first before the structural proteins?
the spikes have affinity for the ACE2 protein found in the membrane of the host lung epithelial cells. the spikes allow the viral particle to initially attach to the host membrane and then promote the fusion of the viral envelope with the host cellular membrane
what is the main function of the protein spikes?
5-6 days
what is the median incubation period for COVID-19?
fever
what is the most common symptom of COVID-19?
it causes a very robust immune response throughout the lungs that causes inflammation of the alveoli. this inhibits gas exchange and causes the alveoli to fill with fluid
how does COVID-19 actually kill you?
true
the three S protein subunits form prominent "spikes" on the surface of the virus. one of the subunits has affinity for the ACE2 receptor, which is embedded in the membrane of host cells. these crownlike spikes give coronaviruses their name.
endoplasmic reticulum and the golgi bodies of the host cell
what is the origin of the membrane envelope of the viral particle?
RNA dependent RNA polymerase (RdRP)
which SARS-CoV protein has homology to the palm, thumb, and fingers domains of DNA polymerase?
envelope of the viral particle
which of the following is not encoded in the viral RNA?
nsp7 and nsp8
which pair of nsp's form a primase to assist the RdRp?
nucleocapsid protein (N)
which protein protects the viral RNA, keeping it stable inside the virus?
nsp13 and nsp15
which two proteins encoded by SAR-COV-2 are translated from the positive strand RNA and are involved in adding or modifying the CAP on viral RNAs?
