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Flashcards in Unit 3 Deck (117):
1

Salmonella enterica phage binds what to enter the host cell

OmpF and TolC efflux pumps

2

E. coli phage lambda uses what to enter the host cell

maltose porin

3

Ebola typically infects what kinds of cells

dendrites, but has broad tropism

4

papillomavirus typically infects what kinds of cells

epithelial cells only

5

enveloped viruses can enter animal cells by

fusion, endocytosis

6

nonenveloped viruses can enter animal cells by

endocytosis only

7

how are viroids pathogenic

changes DNA d. RNA pol to RNA d. RNA pol

8

where and how does Hepatitis B replicate

in nucleus of liver cells using RNA pol I, II, and III

9

PrPc

cellular prion protein; normally functioning helical protein in cell-to-cell communication in brain

10

PrPsc

scrapie prion protein; converted helical to pleated protein; extremely stable

11

mutation in prion protein

G to V at position 127 - highly resistant to Kuru

12

what provides resistance to prion infections

G127V and M129 - possible binding sites for prion

13

influenza classification

Family Orthomyxoviridae, Baltimore Class V

14

influenza basic structure

round, enveloped; matrix protein under envelope; genome of 8 segmented, non-identical (-) RNAs; cap, RNA pol., and capsid associated with each RNA

15

Influenza A hosts

wide host range, rapid mutation

16

Influenza B hosts

humans, seals, ferrets; slow mutation rate

17

Influenza C hosts

humans, dogs, pigs

18

Influenza C spikes

no HA or NA spikes; has HEF hemagglutinin esterase fusion protein

19

Influenza D host

bovine influenza virus

20

what codes for RNA pol in influenza viruses

PB1, PB2, PA

21

HA

hemagglutinin, involved in attachment to sialic acid

22

NA

neuraminidase, involved in egress

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MI

matrix protein

24

NS1 and NS2

involved in nuclear export of RNA

25

M2

ion channel

26

PB1, PB2, PA

RNA pol.

27

antigenic shift

or reassortment: if two viruses infect host at same time, genomes can be repackaged differently, making a hybrid virion

28

antigenic drift

small mutations (RNA d. RNA pol is prone) that lead to changes in resistance and host range

29

sialic acid-galactose bond in birds

alpha 2,3

30

sialic acid-galactose bond in humans

alpha 2,6 (upper resp. tract), alpha 2,3 (lower resp. tract)

31

sialic acid-galactose in pigs

both alpha 2,3 and 2,6 - mixing bowl of viruses

32

left to right organization of lytic/lysogenic genes

CIII - OL (containing left PL for CIII) - CI - OR (containing left PRM and right PR) - Cro - left PRE - CII

33

lysis expression

RecA produced, cleaves CI - no CI means exp. of Cro - Cro blocks left transcription of CI at PRM - allows transcription from promoters PL and PR - lysis

34

lysogenic expression

CII induces transcription of CI from PRE - CI blocks transcription from PL and PR and initiates transcription of CI from PRM to maintain lysogeny

35

CIII

promoter if PL located to the right of the CIII gene - CIII blocks degradation of CII by HflB protease, allows lysogeny

36

CI

allows transcription of CIII from PL and transcription of CII from PR; allows transcription of CI from PRM - allows for lysongeny

37

CII

induces transcription of CI from PRE

38

PL

promoter for CIII found in the OL region; transcribes to the left

39

PRM

promoter for CI found in the OR region; transcribes to the left

40

RecA

UV induced, cleaves CI - no CI present, no transcription from PL and PR - lysis

41

broad range tropism

can infect multiple cell type (ie ebola, dendrites and more)

42

narrow range tropism

specific host cell type (ie HPV only infect human epithelial cells)

43

influenza virus entry

endocytosis (host cell protease cleaves HA into HA1 and HA2), endosome fuses with lysosome, acidification causes conformational change, RNA leaves vesicle

44

tamiflu

neuraminidase inhibitor - prevents egress of virions, active against type A and B if used before or within two days of infection

45

HIV classification

genus lentivirus, family retroviridae, baltimore class VI

46

structure of HIV

icosahedral capsid surrounds entire genome, with matrix protein and envelope

47

HIV genome

2 non-identical strands of + ssRNA - genetically diploid

48

HIV carries which proteins

integrase, protease, reverse transcriptase

49

HIV spike structure

SU surface region (GP 120)
TM transmembrane region (GP41)

50

HIV binding to host cell

GP120 binds to T cell CD4 receptor, interacts with CCR5, conformational change opens spike, fusion peptides pull together, envelope and host membrane fuse

51

CCR5

chemokine co receptor, involved in chemotaxis, indicating where T cells should go

52

reverse transcriptase

has RNA d. DNA pol. activity, RNAse H activity to break RNA-DNA hybrid and degrades RNA, and DNA d. DNA pol. activity

53

benefit of HIV having two copies of RNA genome

RT is very error prone, mutations may render a gene ineffective, still has back up

54

integrase

brings viral DNA into nucleus and integrates into host cell genome by trimming 2 nucleotides from each end of DNA to make sticky ends, then cleaves host DNA at integration site

55

HIV gag

NC protein, matrix, capsid protein

56

HIV pol

RT, integrase, protease

57

HIV env

GP41 and GP120

58

HIV vif

protects RT

59

HIV vpr

slows and stops T cell growth

60

HIV nef

degrades CD4 receptors to prevent superinfection and decreases expression of MHC (involved in immune recognition)

61

HIV vpu

degrades CD4, releases tetherin

62

HIV rev

involved in RNA export

63

HIV tat

transcription factor

64

HIV treatment PI

protease inhibitor - can't cleave long peptide into viral proteins, no new virions

65

HIV treatment NNRTI

non-nucleoside RT inhibitor, binds to and alter fxn on RT

66

HIV treatment NRTI

nucleoside RT inhibitor - looks like ATCG but doesn't act like one - no functional protein

67

HAART

highly active antiretroviral therapy

68

stage 1 HIV

acture stage - flu-like symptoms

69

seroconversion

antobodies produced - during acute stage

70

stage 2 HIV

asymptomatic, latent stage - free of major disease, integrated viral reproduction continues, low levels in blood, increased risk of secondary infxn

71

stage 3 HIV

chronic symptomatic stage, replication continues, CD4+ cells decrease

72

stage 4 HIV

AIDS: less than 200 CD4+ cells per mm cubed blood; HIV producing 10 billion new virions everyday, opportunistic infxn, HIV mutates, risk of TB and cancer

73

how is HIV transmitted

blood

74

zika classification

family flaviviridae baltimore class IV

75

zika structure

enveloped, icosahedral

76

zika host cell entry

binds to AXL RTK involved in signal transduction in developing cortex/retinal cells, glial cells, astrocytes

77

AXL

RTK that mediates zika viral entry - immune system suppressed

78

apoptotic mimicry

after zika entry by endocytosis, signals to immune cells that host cell is apoptotic - doesn't cause immune response

79

zika C

capsid protein

80

zika prM

protects E proteins during assembly

81

zika E

evnelope protein

82

zika NS ##

nonstructural proteins

83

zika exits how

exocytosis - prevents putting spikes on cell membrane so as to avoid immune response

84

sylvatic transmission

in nature, carried by mosquito to non-human primate host

85

suburbabn-urban transmission

carried by mosquito to human hosts

86

vertical transmission of zika

Theory of Antigenic Enhancement - Dengue fever causes immune response; zika causes similar immune response; virus hijacks IgG antibodies to cross placenta

87

polio virus classification

family picornaviridae, baltimore class IV

88

polio structure

non-enveloped, icosahedral

89

polio is an enterovirus

passes fecal-oral route, usually acquired by contaminated food/water

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polio host cell recognition

binds CD155, intracellular junctions between epithelial cells

91

polio infects what types of cells

motor neurons in brainstem, spinal cord, glial cells

92

polio host cell entry and exit

endocytosis entry, lysis exit

93

polio uncoating

happens same time as genome release and endocytosis - similar to bacteriophage

94

genome of polio

single ORF into about 10 proteins

95

polio VP 1, 2, 3, and 4

capsid proteins

96

disease

disturbance in normal functioning of organism

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infectious disease

caused by a microbe, can be transmitted host to host or species to species

98

zoonotic disease

transferred animal host to human host

99

pathogen

microbe associated with disease production

100

pathogenesis

mechanism microbe uses to cause disease

101

infection

replication of a pathogen in/on a host

102

primary pathogen

causes initial infection

103

secondary pathogen

causes secondary infection

104

opportunistic pathogen

part of normal flora, causes infection in case of immunocompromization or break in protective barrier (skin)

105

symptoms

subjective, difficult to quanitify

106

signs

objective, easily measurable

107

virulence

measure of degree of severity of disease

108

LD50

lethal dose 50; amount that must be added to kill 50% of the population (lower number is stronger toxin)

109

ID50

infectious dose 50

110

virulence factors

pathogen products that enhance ability to cause disease

111

virulence factor genes tend to be located

on gene islands (clusters) or plasmids

112

infection cycle

route from one individual to the next

113

horizontal infection cycle

one member of species to the next; may pass through fomite or vector

114

fomite

inanimate object

115

accidental host

not normally part of infectious cycle

116

reservoir

harbors the pathogen, can be both reservoir and vector

117

carrier

infected but asymptomatic; may still be be able to transmit microbe