Virology Flashcards
Post midterm (31 cards)
Zika virus type and genome type
+ssRNA envelopped virus ; polyprotein made into ER membrane (for hydrophobic regions)
What’s Ribavirin? how does it work?
treatment for HCV. nucleoside analog that incorporates itself into rna genome intermediate during replication and causes hypermutations (can be lethal).
A and G analog that can bind to U or C
Hepatitus C Virus (HCV) viral type and genome type.
+ssRNA envelopped virus
whats the name of the treatments for Hep C Virus? how does it work?
Sofosbuvir inhibits RdRp by incorporating into growing HCV RNA molecule (causes chain termination) -> no RNA synthesis.
Ribavirin incorporates itself in RNA replication as nucleoside analog and causes mutations
Covid-19 viral type and genome type.
+ssRNA envelopped virus
how does Paxlovid work?
Paxlovid targets 3CL protease in COVID-19, which prevents the release of RdRp, thus preventing RNA synthesis
what causes programmed ribosomal frameshifting in COVID?
RNA Pseudoknot (secondary structure)
- ribosome is stalled, slips on poly U/A, shifts reading frame -1
- stop codon no longer encountered like the first reading frame, resulting in longer reading frame
What do you call CoV translation without frameshifting?
Canonical Translation
Why is frameshifting important in CoV?
needed to make RdRp
Remdesivir function
RdRp is target. causes chain termination during replication, preventing viral RNA synthesis in COVID-19 virus.
what are replication organelles
made of viral proteins and stolen ER membrane. occurs with COVID-29.
RdRp in there:
1. copies genome
2. makes shorter sub-genomic +ssRNA that encodes structural proteins like spike
Functions:
1. hides viral RNA from PRR
2. Crown-shaped pore allows ribonucleotide in and viral RNA out to be translated (or full length to be packaged in new viral particle)
purpose of neuraminidase in influenza
removes sialic acid from cell surface to allow progeny influenza virus to escape cell and spread
influenza A has ____ HA proteins and _____ NA proteins. their natural reservoir host are _____
18 ; 11 ; birds
does influenza A and B spillover?
A: yes into birds
B: no
how are influenza viruses divided?
genetically distinct HA and NA proteins (ex: H1N1, H3N2)
does influenza A or B cause pandemics?
A because spillover events possible
what are the two currently circulating Influenza B types
Victoria and Yamagata
what virus hasnt been found globally since april 2020? why?
Influenza B - Yamagata
because masking and social distancing, there was no opportunity for spread
antigenic shift vs antigenic drift in influenza
drift: caused by mutation to antigen so antibodies cant bind (mostly located on HA)
shift: from spillover events, caused my segmental genomic rearrangement or swapping of genetic material between another virus (because RdRp ERROR PRONE)
describe the influenza genome
8 segments of -ssRNA that each have their own RdRp
H2N2 pandemic of 1957 caused by ___
bird spillover event
_____ is responsible for 2009 H1N1 pandemic
antigenic shift: two influenza viruses rearranged genomes together when they infected the same cell, making an entirely new influenza virus
explain the process of making vaccines for influenza
isolate desired HA and NA segments. Remove dangerous parts of HA gene. fuse these in circular DNA (2 plasmids). add additional 6 plasmids. insert 8 plasmids into cell. harvest hybrid virus with correct HA/NA antigens. use to inoculate eggs.
icosahedral capsids are built from _____ types of protein subunits
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