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Virology > Exam Uno > Flashcards

Exam Uno Flashcards

1
Q

viruses are smaller than bacteria so what size range do they typically fall into

A

20nm-300nm

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2
Q

all viruses have a protein coat called a ____ to protect genetic info, but not all of them have a lipid based ____.

A

capsid

envelope

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3
Q

what are the five stages of bacteriophage replication

A 
attachment
penetration
biosynthesis
maturation
release
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4
Q

what was the main result of the hershey-chase bacteriophage and bacteria experiment

A

DNA is the genetic material

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5
Q

what is an adenovirus?

retrovirus

A

has dsDNA genome

RNA is converted to dsDNA

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6
Q

viral infections are linked to about ____% of all cancers

A

12

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7
Q

oncolytic viruses are used to kill cancer cells by targeting rapidly growing cells

A

virotherapy

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8
Q

what is the virus name for smallpox varus

A

variola major

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9
Q

what does varus mean

A

mark on skin

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10
Q

dried scab or fluid from smallpox victim turned into powder and sniffed or rubbed into scratches

A

variolation

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11
Q

who invented the first “vaccine”, when and what does vacca mean

A

Edward Jenner
1796
cow

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12
Q

agents that can pass through filters that trap most known bacteria

A

virus

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13
Q

what was the first virus discovered

A

tobacco mosaic virus

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14
Q

what did dmitri ivanovski contribute to science

what was the year

A

found that when grinding up yellow leaves whatever the infectious material was passed through filter indicating it was not a bacteria
1892

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15
Q

what did martinus beijerinck contribute
what was the year
what term did he coin

A

showed that the filtered material could replicate so it was not a toxin
coined the term virus
1898

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16
Q

what did frederick loeffler and paul frosch demonstrate in 1898

A

a filterable agent caused foot and mouth disease in cattle

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17
Q

twort and d’herelle independently discovered what in what year
how did they explain it

A

that there were filterable agents that can destroy bacteria in 1915
twort thought it was due to an enzyme
d’herelle thought it could be useful in treating bacterial disease

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18
Q

what was the mode of transmission for polio

A

human feces

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19
Q

intestinal virus that damages lungs and is shed in feces

A

poliomyelitis

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20
Q

why did the March of Dimes began in 1938

A

to raise money for polio treatment and research

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21
Q

what was the epicenter of the flu outbreak in 2009

A

mexico

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22
Q

how did the flu spread

A

from pigs to humans

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23
Q

what is an R0 value

A

how many ppl can be affected from one person

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24
Q

what percent of deaths were due to ebola in West Africa in 2014-2016

A

39.5%

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25
Q

what percent of deaths were due to ebola in the democratic republic of the congo in 2018

A

66%

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26
Q

about how many viruses cause human disease

A

220

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27
Q

disease transmitted to humans via animals or insects directly

A

zoonosis

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28
Q

what are four causes for new viruses

A

global travel
world-wide animal distribution
changing animal populations to due human expansion
climate change

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29
Q

what are the two most common capsid shapes

A

polyhedral and helical

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30
Q

what is the most common polyhedral? how many sides does it have

A

icosahedral

20

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31
Q

what is 5-3-2 fold symmetry

A

there are 5 capsomeres at each vertex
3 capsomeres per face
2 fold around the edges

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32
Q

what structural proteins make up capsomeres

A

protomers

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33
Q

where does a virus get its cell membrane

A

via the infected cell like the plasma membrane, golgi membrane, nuclear membrane, er membrane

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34
Q

what is the nucleocapsid

does it include the envelope

A

capsid and nucleic acid/genomic info

no

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35
Q

all genes are on one piece of RNA/DNA

A

monopartite; nonsegmented

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36
Q

mutiple pieces of RNA/DNA that code for 1 protein

A

multipartite; segmented

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37
Q

giant DNA-containing virus

A

girus

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38
Q

subviral agents within other big viruses

A

virophages/ satellite virus

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39
Q

what are viruses named after (4)

A

diseases they cause
morphological characteristics
places isolated
discoverers

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40
Q

what are the 7 classes of virus

A
  1. dsDNA
  2. ssDNA
  3. dsRNA
  4. +ssRNA
  5. -ssRNA
  6. RNA reverse transcribing
  7. DNA reverse transcribing
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41
Q 
latin names for these terms:
order
family
subfamily
genus
subgenus
A
  • virales
  • viridae
  • virinae
  • virus
  • virus
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42
Q

polthetic class that has many but not all properties in common

A

species

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43
Q

having distinct properties or immune response

A

strain

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44
Q

altered genetic sequences

A

variant

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45
Q

what virus is described here:
enveloped +ssRNA
has spike proteins
helical nucleocapsid

A

corona

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46
Q

T/F:

SARS-CoV-2 binds to ACE-2 receptor

A

true

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47
Q

what does the +ssRNA code for in coronavirus

A

rna dependent rna polymerase

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48
Q

what is the role of replicase/RdRp

A

makes more genomic RNA that encodes viral proteins

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49
Q

the _______ protein binds genomic RNA

A

nucleocapsid

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50
Q

where does the envelope of the coronavirus come from? how does it leave the cell

A

ER-golgi membrane

exocytosis

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51
Q

what are the 3 serious human coronavirus infections

A

SARS-CoV
MERS
SARS-CoV-2

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52
Q

under which subfamily do SARS-CoV, MERS,

SARS-CoV-2 fall under

A

betacoronavirus

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53
Q

what is primary reservoir for coronavirus

what is the intermediate reservoir

A

bats

civet cats

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54
Q

the SARS-CoV outbreak took place from ____ to ____ and had a ____% mortality rate overall. The mortality rate for ppl over 60 was ___.

A

2002-2003
9
50

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55
Q

Were there asymptomatic SARS-CoV patients?

Is it still in circulation

A

no

nope

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56
Q

The first MERS-CoV outbreak occurred in ____ and has a mortality rate of ____%

A

2012

34

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57
Q

Where were most MERS-CoV cases?

How was it spread?

A

Saudi Arabia

camels

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58
Q

When did the SARS-CoV-2 outbreak start?

what was the mortality rate?

A

2019

2.4%

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59
Q

what are symptoms of SARS-CoV-2

A

increase in respiration rate

decrease in blood oxygen levels

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60
Q

what leads to severe disease after SARS-CoV-2 infection?
why?
what immune cells does it increase? decrease?

A

cytokine storm

it damages tissues due to increase in pro-inflammatory cytokines and reduced lymphocyte counts

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61
Q

when does the cytokine storm usually occur

what period/stage of disease is this

A

second week of disease

ambulatory period

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62
Q

when do viral rna levels drop

A

10 days-2 wks

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63
Q

what is the R naught for SARS-CoV-2

A

2.2

64
Q

What are a majority of coronavirus cases due to

A

asymptomatic or pre-symptomatic indiv

65
Q

there needs to be at least ____% previously infected or immunized to reduce spread of disease to gain herd immunity

A

70

66
Q

what are the phases of clinical trials

A

phase 1: check for safety (20-100)
phase 2: checking for efficacy (100-500)
phase 3: confirm results (1000-5000)
phase 4: FDA review

67
Q

proteins found in/on the virion

A

structural proteins

68
Q

proteins made from viral genes and aid replication but stay inside the infected cell

A

non-structural proteins

69
Q

what direction is DNA synthesized in

A

5’ to 3’

70
Q

which DNA strand has the same code as the RNA strand

A

coding

71
Q

gene produces separate RNAs and protein products

A

monocistronic

72
Q

one long mRNA produces polyprotein that gets cleaved into separate proteins

A

polycistronic

73
Q

what are the 3 ways for viral translation to occur

what do all 3 of these methods allow

A

7mGppp (5’ cap)/ kozak consensus sequence
cap-independent translation
leaky scanning

-for multiple viral proteins to be synthesized from a single mRNA

74
Q

what are 3 posttranslational protein processing methods

A

glycosylation
phosphorylation
cleavage

75
Q

what is a one step growth experiment study?

A

the virus replication cycle

76
Q

what are the steps to a one step growth experiment

A
  1. infect ALL cells
  2. monitor cells using inverted microscope
  3. collect infected cell lysate at various timepoints
  4. perform serial dilutions
  5. stain and analyze plaque assay
77
Q

how many viral particles should be used in one step growth experiment

A

5-10x # of plated cells

78
Q

what is the point at which a virus can’t be detected

A

eclipse

79
Q

why is there a time in which there are no detectable phage particles

A

because they were taken up, disassembled inside the infected cell

80
Q

what are the 6 key steps of the viral replication cycle

talk this card out

A
  1. adsorption
  2. entry
  3. uncoating
  4. replication and expression
  5. assembly
  6. release/maturation
81
Q

what 2 steps are integral to infection

A

prod. of nonstructural and structural proteins

replication of genome

82
Q

most dna viruses replicate in the ____ while rna viruses replicate in the ____

A

nucleus

cytoplasm

83
Q

t/f

+ssRNA gets translated immediately once it enters the cell

A

true

84
Q

t/f

-ssRNA gets translated immediately once it enters the cell

A

false; it needs RdRp to make a + sense strand

85
Q

dsRNA have RNA dependent RNA polymerase

A

yes

86
Q

which strand does RdRp translate in dsRNA virus

A

negative!

87
Q

what converts +ssRNA to dsDNA in a retrovirus

where does the dsDNA go and what does it do

A

reverse transcriptase

goes into the nucleus and integrates into the chromosome

88
Q

how do helical and small icosahedral viruses assemble?

large icosahedral?

A

self assemble due to attractive forces

rely on scaffolding proteins for capsids and pilot proteins for nucleic acids

89
Q

stage in life cycle when virus becomes infectious

A

maturation

90
Q

how does cleavage play a role in viral infectiousness

A

some viral proteins need to be cleaved to become icky

91
Q

what 3 way are viruses are released

A

lysis
budding
exocytosis

92
Q

antiviral used to treat chickenpox (Varicella Zoster virus) via chain termination
it’s a nucleoside analog of ____
phosphorylated by viral enzyme _____

A

acyclovir
guanosine
thymidine kinase

93
Q

antiviral used to treat HIV that leads to chain termination
analog of _____
it gets used by _____________ when making viral DNA

A

AZT
thymidine
reverse transcriptase

94
Q

what is the preferred route of entry for viruses

what are the 4 most common

A 
mucous membranes
respiratory tract
gastrointestinal tract
genital tract 
conjunctiva
95
Q

what are the 3 most common ways a virus spreads

A

aerosol
fecal-oral
sexual

96
Q

what immune defenses are in the respiratory tract

A

IgG
IgA
macrophages
mucous

97
Q

t/f

respiratory viruses can spread to other parts of the body

A

true

98
Q

rhinovirus causes about ____% of common colds

A

50

99
Q

what are 3 viruses that enter via the fecal-oral route

A

norovirus
poliovirus
hepatitis A

100
Q

____ viruses are more stable in water than ___ viruses

A

naked

enveloped

101
Q

how do viruses enter the skin

A

via a cut

102
Q

what is an iatrogenic induction

A

hospital caused virus

103
Q

how can iatrogenic induction occur

A

bone marrow/organ transplants

transfusion and blood products

104
Q

what are common skin entry methods

A

insects
animal bites
dirty needles

105
Q

what are the two types of viral infections

A

localized and systemic

106
Q

what are two examples of localized viral infections

A

rhinovirus

norovirus

107
Q

infection that spreads to other susceptible organs via the blood and lymphatic system/ nervous system

A

systemic viral infection

108
Q

what are three examples of a systemic viral infection

A

measles
rabies
chickenpox

109
Q

how do severe infections affect birth/pregnancy

A

spontaneous abortion
stillbirth
neonatal death
congenital malformations

110
Q

how does pregnancy affect viral susceptibility

A

few cytokines circulating
IgG moves across placenta
normal Ab production

111
Q

what are the four patterns of viral infections

A

acute
acute followed by persistent latent
chronic
slow

112
Q 
what is an example of each viral infection:
acute
acute followed by persistent latent
chronic
slow
A

cold
herpes 1/2
hepatitis b/c
hiv/prion disease

113
Q

where are human viruses usually shed from

A

their routes of entry

114
Q

what are 5 factors that affect virus survival

A 
pH
humidity
temp
viral composition
if found in organic matter
115
Q

what is the genome size range for:
RNA virus
DNA virus

A

6 kb-30 kb

3.2 kb- 250 kb

116
Q

what are ways viruses can be used in medicine

A

gene therapy and bacteriophage therapy

117
Q

what was the mortality rate for smallpox in adults?

children

A

10-20%

70%

118
Q

where did the variolation technique originate

A

china, india, middle east

119
Q

what type of filter was used that led to the discovery of viruses

A

chamberland porcelain ultrafilters

120
Q

what did scientists landsteiner and popper do

what year

A

1908

try to determine the cause of polio eventually infected monkeys

121
Q

what year was the hershey chase experiment

A

1952

122
Q

when was the first pandemic and what was the disease

A

influenza

1918

123
Q

constantly present at some level

A

endemic

124
Q

sudden spike beyond expected levels

A

epidemic

125
Q

worldwide epidemic

A

pandemic

126
Q

what was the time frame for the polio epidemic

A

1916-1940

127
Q

what year did the H1N1 epidemic occur

what was the animal vector

A

2009

pigs!

128
Q

what are some key viral properties

A 
capsid made up of repeating capsomers
all have a capsid to protect genome
need proteins/glycoproteins on surface for binding
self assembly and disassembly
small genome and proteins
129
Q

where do the measles and smallpox virus start in the body? where do they move
what does it cause

A

start in the respiratory tract and then enters the blood and lymphatic system
lesions and rashes

130
Q

where does rabies initially replicate and where does it move

A

initially in muscle cells where the person was bitten and then moves to the peripheral nervous system, to the central nervous system to the brain

131
Q

where does the chickenpox virus start and where does it move

A

starts in the upper respiratory tract then moved to the spleen and liver and skin via the blood and lymphatic system

132
Q

what type of cell is latently infected by chickenpox

A

neurons

133
Q

t/f

viruses can only be transmitted during birth

A

false! they can be transmitted during, before, and after birth

134
Q

what 2 viruses can lead to neonatal death, stillbirth or spontaneous abortion

A

smallpox

CMV

135
Q

what 2 viruses can lead to congenital malformations

A

zika

rubella (german measles)

136
Q

is it possible to shed a virus if you are asymptomatic

A

yes!

137
Q

t/f

viruses typically prefer warm temperatures

A

false

they are chilly bois

138
Q

what are some non-protein coding sequences

A

introns
non-coding rna genes
promoters and enhancers

139
Q

t/f

dna replication is semi-conservative

A

true

140
Q

how do you tell the 5’ end from the 3’ end of dna

A

5’ has triphosphates

3’ has a free OH

141
Q

what is leaky scanning
when does it happen
what does it allow

A

when the ribosome bypasses the first AUG to initiate translation downstream
when there’s a lack of Kozak sequence near the first AUG
allows for multiple proteins to be synth from 1 viral RNA

142
Q

what are four ways the capsid can be removed

A

degradation
transport to locations that cause stress
alter capsid proteins during attachment
during the fusion process

143
Q

where do enveloped viruses tend to assemble

A

near the plasma membrane

144
Q

number of cycles takes to amplify past the baseline fluorescence threshold

A

Ct

145
Q

detects corona virus specific transcripts

A

qRT-PCR

146
Q

what does qRT-PCR measure

what does faster accumulation mean

A

the amount of viral RNA transcripts

more viral RNA present

147
Q

which genes does qRT-PCR look for

A

N gene
RdRp gene
E gene

148
Q

what are the three stages of qRT-PCR and what temperatures do they occur at
how many times do you repeat these stages

A

denaturing: 95 C
annealing: 60 C
elongation: 70 C
40

149
Q

what are the four steps to qRT-PCR

A

isolate rna
dnase rxn
reverse transcription
qPCR

150
Q

what Ct value typically indicates a positive test for qRT-PCR

A

<35

151
Q

immunoassay used to detect specific viral protein

A

antigen testing

152
Q

what is the protein typically tested for when doing antigen testing

A

N protein

153
Q

what does a positive antigen test look like

A

visible control and test line

154
Q

t/f

antigen testing has a higher sensitivity rate compared to qRT-PCR and less accurate

A

false

has lower sensitivity but is more accurate

155
Q

when is peak viral load seen in COVID patients

A

onset of symptoms or 1st week

156
Q

is receptor mediated endocytosis pH independent or dependent

A

pH dependent

157
Q

is receptor mediated signaling pH independent or dependent

A

independent

Virology (5 decks)

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