Virology

Question 1

Zika virus type and genome type

Answer 1

+ssRNA envelopped virus ; polyprotein made into ER membrane (for hydrophobic regions)

Question 2

What’s Ribavirin? how does it work?

Answer 2

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

Question 3

Hepatitus C Virus (HCV) viral type and genome type.

Answer 3

+ssRNA envelopped virus

Question 4

whats the name of the treatments for Hep C Virus? how does it work?

Answer 4

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

Question 5

Covid-19 viral type and genome type.

Answer 5

+ssRNA envelopped virus

Question 6

how does Paxlovid work?

Answer 6

Paxlovid targets 3CL protease in COVID-19, which prevents the release of RdRp, thus preventing RNA synthesis

Question 7

what causes programmed ribosomal frameshifting in COVID?

Answer 7

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

Question 8

What do you call CoV translation without frameshifting?

Answer 8

Canonical Translation

Question 9

Why is frameshifting important in CoV?

Answer 9

needed to make RdRp

Question 10

Remdesivir function

Answer 10

RdRp is target. causes chain termination during replication, preventing viral RNA synthesis in COVID-19 virus.

Question 11

what are replication organelles

Answer 11

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)

Question 12

purpose of neuraminidase in influenza

Answer 12

removes sialic acid from cell surface to allow progeny influenza virus to escape cell and spread

Question 13

influenza A has ____ HA proteins and _____ NA proteins. their natural reservoir host are _____

Answer 13

18 ; 11 ; birds

Question 14

does influenza A and B spillover?

Answer 14

A: yes into birds
B: no

Question 15

how are influenza viruses divided?

Answer 15

genetically distinct HA and NA proteins (ex: H1N1, H3N2)

Question 16

does influenza A or B cause pandemics?

Answer 16

A because spillover events possible

Question 17

what are the two currently circulating Influenza B types

Answer 17

Victoria and Yamagata

Question 18

what virus hasnt been found globally since april 2020? why?

Answer 18

Influenza B - Yamagata

because masking and social distancing, there was no opportunity for spread

Question 19

antigenic shift vs antigenic drift in influenza

Answer 19

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)

Question 20

describe the influenza genome

Answer 20

8 segments of -ssRNA that each have their own RdRp

Question 21

H2N2 pandemic of 1957 caused by ___

Answer 21

bird spillover event

Question 22

_____ is responsible for 2009 H1N1 pandemic

Answer 22

antigenic shift: two influenza viruses rearranged genomes together when they infected the same cell, making an entirely new influenza virus

Question 23

explain the process of making vaccines for influenza

Answer 23

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.

Question 24

icosahedral capsids are built from _____ types of protein subunits

Answer 24

4

Question 25

2 ways envelopped virions escape cells, and 2 examples of each.;

Answer 25

1. budding into internal mem then exocytosis
   - coronavirus
   - herpes
2. budding straight from PM
   - influenza
   - HIV

Question 26

2 names of drugs that stop NA from working, keeping influenza stuck on cell surface (bound to sialic acid via HA).

Answer 26

1. Tamiflu
2. Relenza

Question 27

how do influenza virus genome segments know where to be incorporated into new virion?

Answer 27

has packing signal on end (As well as nucleoproteins and RdRp)

Question 28

where does herpesvirus first and second envelopes come from?

Answer 28

1st: nuclear enveloppe
2nd: Golgi

Question 29

site of covid assembly

Answer 29

ERGIC : ER-Golgi Intermediate Compartment

Question 30

how does Covid know which RNA to package into viral particles?

Answer 30

only full length +ssRNA has packaging signal