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Jason's Respiratory Block > Viruses > Flashcards

Flashcards in Viruses Deck (40):
1

How do viruses differ in their replication cycle?

Viruses have an eclipse/latent period then burst
Bacteria just linearly replicate from the get go

2

6 stages in viral replication

1. attachment
2. penetration
3. uncoating
4. genome replication, RNA synthesis, protein synthesis
5. assembly
6. RELEASE THE KRAKKEN!

3

Viral attachment to specific receptors on hosts does what?

limited the host species/type of cell

4

2 kinds of receptors for viruses to attach?

protein (ICAM-1 for rhinoviruses)
Carbohydrate (sialic acid for influenza)

5

HIV uses two receptors to attach: explain

on initial CD4
then CCR5 locks it in

6

2 ways to penetrate a cell as a virus:

1. fuse with host cell membrane
2. endocytosis

7

Do fusing with cell membrane viruses have envelopes?

yes

8

Do endocytosis viruses have envelopes?

Yes and they don't need them either.

9

HIV penetrates how?

Fusion of region gp41

10

What's an example of a virus that is endocytosed?

togavirus

11

DNA viruses replicate where? exception?

nucleus except for influenza(RNA)

12

RNA viruses replicate where? exception?

cytoplasm except for poxvirus(DNA)

13

What's vital for viral protein transcription initially?

mRNA

14

What are early viral proteins?

non structural

15

What are late viral proteins?

structural (capsids)

16

How does an RNA virus replicate?

needs RNA dependent DNA polymerase

17

Poliovirus is a plus sense ssRNA, how does it replicate?

goes right to translation to make proteins
auto cleavage of parts
one is a RNA polymerase to make more copies

18

What happens with a -ve sense ssRNA virus?

need to bring your own polymerases (BYOP)

19

Why would a retrovirus want to go back to DNA?

It needs to be DNA to insert itself in the host genome

20

2 viruses that need their own polymerase?

Pox
Hepadna

21

Translation is done how and by whom?

Host cell ribosomes in cytoplasm

22

when do you need virus coded proteases?

post-translational cleavage of viral polyproteins

23

What's glycosylation in viral replication?

envelope glycoproteins in RER and golgi get deposited on underside of cell surface

24

Why glycosylation?

for budding of enveloped viruses

25

T/F? All non-enveloped viruses are helical?

Nope. Icosahedral

26

Assembly of non-enveloped viruses happen 2 ways:

1. spontaneous assembly
2. proteolytic cleavage to induce assembly

27

Do non-enveloped viruses bud?

Nope.

28

Two viruses that bud?

Flu
Measles

29

Besides budding and lysing out, is there another way viruses can exit the cell?

Elementary Watson. some enveloped viruses use the golgi vesicles' secretary pathway

30

Example of a virus that uses the secretory pathway?

corona virus

31

4 virus induced changes in cells?

Oncogenic
lytic
chronic
latent

32

What' s the difference between chronic and latent viral infection?

Chronic is slow release, no cell death
latent is dormant, emerges later as lytic

33

What are cytopathic effects?

changes in virus infected cells you can SEE on light microscope

34

What are inclusion bodies re: viruses

viral proteins visible at site of virus assembly

35

The goal of a virus isn't to turn a cell cancerous, how does it happen?

The virus oncogenes are growth promoting genes that 'accidentally' lead to uncontrolled proliferation of infected cell

36

What kind of inhibition do cancer cells lack?

contact inhibition

37

3 ways viral genetics change?

mutation
recombination (DNA viruses)
reassortment (swapping of segments e.g.. flu/rota)

38

4 ways to halt viruses

1. antibodies
2. kill infected cell via CD8, NK
3. interferon
4. antiviral drugs

39

do antivirals work on classes of viruses?

NOPE. very specific

40

How does acyclovir work?

It's a nucleoside analog, it mimics guanosine, but missing a key component to extend DNA polymer, so in the infected cell, it uses the analogue and termination occurs cause it can't replicate