Lecture 1: Viruses 1 Flashcards Preview

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Flashcards in Lecture 1: Viruses 1 Deck (55):
1

hookworm

99% of time no symptoms
hook on and feed on blood
big b4 sanitation...pretty much EVERYONE had them
they can crawl 4 feet, so latrine are really deep
enter through skin of feet, leave in feces
CAN cause anemia... its rare

2

hookworm and allergies

ppl with hookworm have fewer allergies...
because they used to be a part of the normal flora?
mast cells mointor worms and allergies...
hookworms could probably regulate activity of mast cells to make them less reactive

3

hookworms in the south pre Civi war

the hookworms of the African slaves weree different since Africans and Europeans had been genetically isolated
so hookworms were genetically different
these hookworms caused sudden anemia in Southern US

4

size of viruses

sub-microscopic... cant see with microscope

5

virus

infect eukaryotes

6

bacteriophage

"viruses" that infect bacteria

7

adenovirus

cold

8

rhinovirus

cold

9

chlamydia elementary body

NOT a virus

but its very small and cant live by itself

10

prions

proteins that cause diseases
NO NUCLEIC ACIDS (no genetic material)
but still infectious

11

are viruses living?

NO

12

WHY are viruses not living?

because they DON'T have RIBOSOMES
this means they can't complete the central dogma

13

REVIEW SLIDE 5!!

table about bacteria vs. viruses

14

Bacteria vs. Virus (and chlamydias)
INTRACELLULAR PARASITE?

Bact: NO
Chlamydia: YES
Virus: YES... MUST replicate inside cell

15

Bacteria vs. Virus (and chlamydias)
PLASMA MEMBRANE?

Bacteria: Yes
Chlamydia: Yes
Virus: NO... but some steal host membrane

16

Bacteria vs. Virus (and chlamydias)
BINARY FISSION?

Bacteria: Yes
Chlamydia: Yes
Virus: No

17

Bacteria vs. Virus (and chlamydias)
MOVE THROUGH BACTERIOLOGICAL FILTER?

Bacteria: No
Chlamydia: no/yes (EBs do)
Virus: No

18

Bacteria vs. Virus (and chlamydias)
Posses DNA AND RNA?

Bacteria: yes
Chlamydia: yes
Virus: NO! one or the other

19

Bacteria vs. Virus (and chlamydias)
ATP generating metabolism?

Bacteria: yes
Chlamydia:yes/no
Virus: no

20

Bacteria vs. Virus (and chlamydias)
Ribosomes?

Bacteria: yes
Chlamydia: yes
Virus: NO!

21

Bacteria vs. Virus (and chlamydias)
Sensitive to Antibiotics?

Bacteria: yes
Chlamydia: yes
Virus: no

22

Bacteria vs. Virus (and chlamydias)
Sensitive to Interferon (increased activity of proteosome)?

Bacteria: no
Chlamydia: no
Virus: YES

23

does the ability to use ATP mean something is livng/not living?

NO
its ribosome possession

24

Minimum requirements of viruses (for the most part)

-have genome (DNA or RNA)
-be able to replicate genome inside cell
-can transcribe and translate its genome
-can assemble into infectious units (virions)
-must be able to get out of the cell

25

virion

extracellular unit of virus
infectious unit
replicative form of virus inside cell

26

things LIFECYCLE require

cell
virion

27

ways virus can get out of cell

budding/eggressing: doesn't harm host cell
lytic: cell explodes

28

parts of the virus

- nucleic acid: DNA or RNA... these can be PAMPS if they're different from normal host cells!
- capsid
- envelopes and spikes

29

DNA types

single stranded (+)
double stranded (+).....can be reverse transcribed

30

RNA types

Single stranded (+/-)... reverse transcribed
Double stranded

31

"reverse transcribed" RNA

going from RNA to DNA to RNA

32

"reverse transcribed" DNA

going from DNA to RNA to DNA

33

+/- and ribosome ability to read mRNA

+ strand... can read mRNA directly
- strand... must make the complement (+ strand) so the ribosome can read the mRNA

34

capsid

protein coat that covers viral genome IN the virion
protein(s) for attaching to/entering cell
subunit=capsomere
shapes: helical, polyhedral, complex

35

capsomere

single subunit of capsid
made of proteins encoded with virus genome
may be one or more proteins

36

Best shape

Icosahedron
20 sides
triangle
really strong and has space inside for genome

37

Envelope

not all viruses are enveloped
envelope made of lipid, protein, carbohydrate
derived from HOST cell membranes
Purpose: protection from immune system bc it looks like self

38

Spikes

proteins/carbohydrate complex on virion surface
viral proteins that protrude through the envelope
purpose: adhesion, attachment

39

Lytic

causes bacteria to lyse so virus can get out

40

egress

mature virions get out of cell without killing
like secretion system from first exam

41

lysogenic

(pro)phage or provirus goes dormant and becomes part of the genome
not currently active

42

Bacterial Phage vs Virus

totally genetically distinct from eukaryotic viruses
evolved separately
same 4 genome types
same capsid, shapes, ways of escaping host cell
lots of separate evolution to icosahedron shape... EFFIECINCY of replication

43

escaping form Gram negative host bacteria cell

hard to get out because 2 membranes...
EGRESS... make a tube to escape
very similar to type 3 and 4 secretion/flagella

44

What came first: Flagella or virus

a) flagella may have gotten a genome and escaped
b) bacteria cell may have captured a virus

45

what is the evolutionary advantage of a bacteriophage

horizontal transfer of genetic material
since bacteria don't sexually reproduce

46

what drives viral evolution?

efficiency
ability to evade immune system

47

Lambda phage

necked virion
virion=no metabolism inside
pin that IDs the right host and pokes a hole in the host
50,000 base pairs (thats a lot)

48

How does the Lambda phage get the genetic info across the membrane without ATP?

SPRINGS
2 sets:
1) the sitting of the pin to poke the hole, nrg stored in sheets released
2) lack of water in capsid... water enters after poke and the DNA unwinds and enters cell

49

How does lambda phage find E. coli host?

recognized LamB protein on host surface
(molecular pattern recognition like our immune system does)

50

after sitting on host

sheath collapses, nrg release
rehydration of capsid with DNA
genome shoved into host cytosol

51

after getting in

biosynthesis... transcription by RNA POLYMERASE in bacteria cytosol
copies of genome and proteins made

52

while copies are being made

lambda phages self assemble
dont need ATP for assembly into cool shape

53

after self assembly

lambda phage leaves

54

the head protein of the lambda phage

requires ATP to dehydrate the capisd
dna get wound really tight in absence of water

55

lytic vs. lysogenic phages of lambda phage

lytic: phage lyses host cell after it uses it
lysogenic: integration into host genome. prophage replicates...
prophage release if cell stress occurs