Flashcards
L23 - COVID
Flashcards do conjunto (31)
- 1give the virus type of COVIDenveloped +ssRNA
- 2how many types of viral glycoprotein are on COVIDjust 1 type
- 3what receptor does the spike protein bind tothe ACE 2 receptor
- 4what are the 2 regions of the spike proteinS1 and S2 regions
- 5where is ACE 2 foundAirway epithelia
- 6give the stages of receptor mediated endocytosis after the spike protein binds to ACE2- binding causes the virus to be taken into the endosome
- viral envelope fuses with the endosome releasing the viral RNA - 7what is the alternative pathway of COVID entry to the cellspike protein binding
makes a pore through which the virus enters - 8do many cells of the body express ACE2- yes including heart, eyes, liver, kidney, bladder, brain, prostate and testis etc
- just cant enter all of these cells tho - 9why does COVID only invade epithelail celsbecause the other cells dont have any of the 3 host proteases needed for COVID entry
- 10what are the 3 host proteases required for COVID entryFurin, Temperas 2, Cathepsin L
- 11where on/in the host cell are furin, TMPRS2 and cathepsin found- furin and TEMPRS2 are on surface membrane
- cathepsin found in lysosomes - 12which entry pathways are each of the follwoing proteins involved in: furin, TEMPRS2 and Capthesin- furin + capthesin involved in endocytosis pathway
- Furin + TMPRSS2 involved in direct fusion pathway - 13give the stages of receptor mediated endocytosis- spike protien binds to ACE2 causing endocytosis
- Furin cleaves Spike protein activating it
- further proteolysis by cathepsin allows fusion of envelope with endosome membrane to realse the RNA - 14give the stages of direct fusion with plasma membrane- spike binds to ACE2
- Spike cleaves by furin removing S1 from S2
- TMPRSS2 cleaves S2 site causing relase of fusion protiens allowing fusion with plasma membrane - 15give the lifecycle of COVID when inside the cell+ ssRNA is translated straight away into proteins including RDRP
- RDRP causes polymerisation of more viral RNA
- both processes cycle to produce many more viral proteins and ssRNA
- viral proteins and ssRNA packaged into new virus capsid which can be exocytosed - 16what cellular organelle is used to make transcriptase complex for viral vesicelsthe ER
- 17why does the virus need to make negative sense ssRNA from its positive sense RNA?to be used as a template to make more positive sense RNA from
- 18what enzyme is used to make - senseRNA from positive sense?RDRP
same enzyme used to make positive sense from negative sense - 19other than lack of proofreading why else do RNA viruses mutate so quicklytheyre much smaller which increases chance of good mutation and decreases chance of a bad mutation remaining in the gene pool
- 20why does a small virus have a lower chance of a bad mutation being passed on?because such a small genome so if a mutation is shit itll probably shut the whole virus down and wont show up
(unlike in larger viruses which would make a new but shit virus) - 21do host cells make RNA dependant RNA polymerasno which is why the virus encodes for RDRP on their gene
- 22give a few reasons why RNA genomes ar eprone to mutation- RDRP has much lower accuracy than DNA polymerase
- no proofreading
- bases in ssRNA are not paired which leaves them exposed allowing for alterations of the bases - 23why does covid have a lower mutation rate than other RNA viruses- is a larger virus
- encodes exonuclease enzymes (NSP14) which gives the RNA polymerase a degree of proofreading - 24how does NSP14 affect RT inhibitors?decreases efficiency of nucleoside RTI's because the NSP14 proofreading will remove the nuceloside and inactivate the treatment
- 25how does COVID mutate through recombinationrecombining genes with other virus in the same cell increases genetic diversity
- 26what has a low mutation rate meant for COVID varientshaven't been many different subtypes/ varients compared to what youd see in other viruses
- 27what mutation was found on the alpha strain which increased transmittion but also immune responsehigher number of spike proteins on surface
- increases binding to host cells but also to immune cells and antibody - 28what mechanism is used by the virus to reduce immune cell/ antibody binding to the spike proteincan change the conform between active and inactive conforms to hide the binding site
- 29give some effects of mutations which affected the S1/S2 furin cleavage sitesincreased positive charges of the spike
increased tissue tropism
increased S1/S2 cleavage - 30what does mutation which antagonises interferon in the host cell domeans the inate immunity doesnt function as well
- 31which of the strains has the best resmonse by vaccinesthe alpha strain - we remain immune to that strain
Informações
- Descrição
- Year 2 I&I. FlashCards sobre L23 - COVID, criado por Jack Rowe em 02-01-2023.
- Criado por
- Jack Rowe
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