Exam Uno Flashcards
1
Q
viruses are smaller than bacteria so what size range do they typically fall into
A
20nm-300nm
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
3
Q
what are the five stages of bacteriophage replication
A
attachment penetration biosynthesis maturation release
4
Q
what was the main result of the hershey-chase bacteriophage and bacteria experiment
A
DNA is the genetic material
5
Q
what is an adenovirus?
retrovirus
A
has dsDNA genome
RNA is converted to dsDNA
6
Q
viral infections are linked to about ____% of all cancers
A
12
7
Q
oncolytic viruses are used to kill cancer cells by targeting rapidly growing cells
A
virotherapy
8
Q
what is the virus name for smallpox varus
A
variola major
9
Q
what does varus mean
A
mark on skin
10
Q
dried scab or fluid from smallpox victim turned into powder and sniffed or rubbed into scratches
A
variolation
11
Q
who invented the first “vaccine”, when and what does vacca mean
A
Edward Jenner
1796
cow
12
Q
agents that can pass through filters that trap most known bacteria
A
virus
13
Q
what was the first virus discovered
A
tobacco mosaic virus
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
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
16
Q
what did frederick loeffler and paul frosch demonstrate in 1898
A
a filterable agent caused foot and mouth disease in cattle
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
18
Q
what was the mode of transmission for polio
A
human feces
19
Q
intestinal virus that damages lungs and is shed in feces
A
poliomyelitis
20
Q
why did the March of Dimes began in 1938
A
to raise money for polio treatment and research
21
Q
what was the epicenter of the flu outbreak in 2009
A
mexico
22
Q
how did the flu spread
A
from pigs to humans
23
Q
what is an R0 value
A
how many ppl can be affected from one person
24
Q
what percent of deaths were due to ebola in West Africa in 2014-2016
A
39.5%
25
what percent of deaths were due to ebola in the democratic republic of the congo in 2018
66%
26
about how many viruses cause human disease
220
27
disease transmitted to humans via animals or insects directly
zoonosis
28
what are four causes for new viruses
global travel
world-wide animal distribution
changing animal populations to due human expansion
climate change
29
what are the two most common capsid shapes
polyhedral and helical
30
what is the most common polyhedral? how many sides does it have
icosahedral
| 20
31
what is 5-3-2 fold symmetry
there are 5 capsomeres at each vertex
3 capsomeres per face
2 fold around the edges
32
what structural proteins make up capsomeres
protomers
33
where does a virus get its cell membrane
via the infected cell like the plasma membrane, golgi membrane, nuclear membrane, er membrane
34
what is the nucleocapsid
| does it include the envelope
capsid and nucleic acid/genomic info
| no
35
all genes are on one piece of RNA/DNA
monopartite; nonsegmented
36
mutiple pieces of RNA/DNA that code for 1 protein
multipartite; segmented
37
giant DNA-containing virus
girus
38
subviral agents within other big viruses
virophages/ satellite virus
39
what are viruses named after (4)
diseases they cause
morphological characteristics
places isolated
discoverers
40
what are the 7 classes of virus
1. dsDNA
2. ssDNA
3. dsRNA
4. +ssRNA
5. -ssRNA
6. RNA reverse transcribing
7. DNA reverse transcribing
41
```
latin names for these terms:
order
family
subfamily
genus
subgenus
```
- virales
- viridae
- virinae
- virus
- virus
42
polthetic class that has many but not all properties in common
species
43
having distinct properties or immune response
strain
44
altered genetic sequences
variant
45
what virus is described here:
enveloped +ssRNA
has spike proteins
helical nucleocapsid
corona
46
T/F:
| SARS-CoV-2 binds to ACE-2 receptor
true
47
what does the +ssRNA code for in coronavirus
rna dependent rna polymerase
48
what is the role of replicase/RdRp
makes more genomic RNA that encodes viral proteins
49
the _______ protein binds genomic RNA
nucleocapsid
50
where does the envelope of the coronavirus come from? how does it leave the cell
ER-golgi membrane
| exocytosis
51
what are the 3 serious human coronavirus infections
SARS-CoV
MERS
SARS-CoV-2
52
under which subfamily do SARS-CoV, MERS,
| SARS-CoV-2 fall under
betacoronavirus
53
what is primary reservoir for coronavirus
| what is the intermediate reservoir
bats
| civet cats
54
the SARS-CoV outbreak took place from ____ to ____ and had a ____% mortality rate overall. The mortality rate for ppl over 60 was ___.
2002-2003
9
50
55
Were there asymptomatic SARS-CoV patients?
| Is it still in circulation
no
| nope
56
The first MERS-CoV outbreak occurred in ____ and has a mortality rate of ____%
2012
| 34
57
Where were most MERS-CoV cases?
| How was it spread?
Saudi Arabia
| camels
58
When did the SARS-CoV-2 outbreak start?
| what was the mortality rate?
2019
| 2.4%
59
what are symptoms of SARS-CoV-2
increase in respiration rate
| decrease in blood oxygen levels
60
what leads to severe disease after SARS-CoV-2 infection?
why?
what immune cells does it increase? decrease?
cytokine storm
| it damages tissues due to increase in pro-inflammatory cytokines and reduced lymphocyte counts
61
when does the cytokine storm usually occur
| what period/stage of disease is this
second week of disease
| ambulatory period
62
when do viral rna levels drop
10 days-2 wks
63
what is the R naught for SARS-CoV-2
2.2
64
What are a majority of coronavirus cases due to
asymptomatic or pre-symptomatic indiv
65
there needs to be at least ____% previously infected or immunized to reduce spread of disease to gain herd immunity
70
66
what are the phases of clinical trials
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
proteins found in/on the virion
structural proteins
68
proteins made from viral genes and aid replication but stay inside the infected cell
non-structural proteins
69
what direction is DNA synthesized in
5' to 3'
70
which DNA strand has the same code as the RNA strand
coding
71
gene produces separate RNAs and protein products
monocistronic
72
one long mRNA produces polyprotein that gets cleaved into separate proteins
polycistronic
73
what are the 3 ways for viral translation to occur
| what do all 3 of these methods allow
7mGppp (5' cap)/ kozak consensus sequence
cap-independent translation
leaky scanning
-for multiple viral proteins to be synthesized from a single mRNA
74
what are 3 posttranslational protein processing methods
glycosylation
phosphorylation
cleavage
75
what is a one step growth experiment study?
the virus replication cycle
76
what are the steps to a one step growth experiment
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
how many viral particles should be used in one step growth experiment
5-10x # of plated cells
78
what is the point at which a virus can't be detected
eclipse
79
why is there a time in which there are no detectable phage particles
because they were taken up, disassembled inside the infected cell
80
what are the 6 key steps of the viral replication cycle
| talk this card out
1. adsorption
2. entry
3. uncoating
4. replication and expression
5. assembly
6. release/maturation
81
what 2 steps are integral to infection
prod. of nonstructural and structural proteins
| replication of genome
82
most dna viruses replicate in the ____ while rna viruses replicate in the ____
nucleus
| cytoplasm
83
t/f
| +ssRNA gets translated immediately once it enters the cell
true
84
t/f
| -ssRNA gets translated immediately once it enters the cell
false; it needs RdRp to make a + sense strand
85
dsRNA have RNA dependent RNA polymerase
yes
86
which strand does RdRp translate in dsRNA virus
negative!
87
what converts +ssRNA to dsDNA in a retrovirus
| where does the dsDNA go and what does it do
reverse transcriptase
| goes into the nucleus and integrates into the chromosome
88
how do helical and small icosahedral viruses assemble?
| large icosahedral?
self assemble due to attractive forces
| rely on scaffolding proteins for capsids and pilot proteins for nucleic acids
89
stage in life cycle when virus becomes infectious
maturation
90
how does cleavage play a role in viral infectiousness
some viral proteins need to be cleaved to become icky
91
what 3 way are viruses are released
lysis
budding
exocytosis
92
antiviral used to treat chickenpox (Varicella Zoster virus) via chain termination
it's a nucleoside analog of ____
phosphorylated by viral enzyme _____
acyclovir
guanosine
thymidine kinase
93
antiviral used to treat HIV that leads to chain termination
analog of _____
it gets used by _____________ when making viral DNA
AZT
thymidine
reverse transcriptase
94
what is the preferred route of entry for viruses
| what are the 4 most common
```
mucous membranes
respiratory tract
gastrointestinal tract
genital tract
conjunctiva
```
95
what are the 3 most common ways a virus spreads
aerosol
fecal-oral
sexual
96
what immune defenses are in the respiratory tract
IgG
IgA
macrophages
mucous
97
t/f
| respiratory viruses can spread to other parts of the body
true
98
rhinovirus causes about ____% of common colds
50
99
what are 3 viruses that enter via the fecal-oral route
norovirus
poliovirus
hepatitis A
100
____ viruses are more stable in water than ___ viruses
naked
| enveloped
101
how do viruses enter the skin
via a cut
102
what is an iatrogenic induction
hospital caused virus
103
how can iatrogenic induction occur
bone marrow/organ transplants
| transfusion and blood products
104
what are common skin entry methods
insects
animal bites
dirty needles
105
what are the two types of viral infections
localized and systemic
106
what are two examples of localized viral infections
rhinovirus
| norovirus
107
infection that spreads to other susceptible organs via the blood and lymphatic system/ nervous system
systemic viral infection
108
what are three examples of a systemic viral infection
measles
rabies
chickenpox
109
how do severe infections affect birth/pregnancy
spontaneous abortion
stillbirth
neonatal death
congenital malformations
110
how does pregnancy affect viral susceptibility
few cytokines circulating
IgG moves across placenta
normal Ab production
111
what are the four patterns of viral infections
acute
acute followed by persistent latent
chronic
slow
112
```
what is an example of each viral infection:
acute
acute followed by persistent latent
chronic
slow
```
cold
herpes 1/2
hepatitis b/c
hiv/prion disease
113
where are human viruses usually shed from
their routes of entry
114
what are 5 factors that affect virus survival
```
pH
humidity
temp
viral composition
if found in organic matter
```
115
what is the genome size range for:
RNA virus
DNA virus
6 kb-30 kb
| 3.2 kb- 250 kb
116
what are ways viruses can be used in medicine
gene therapy and bacteriophage therapy
117
what was the mortality rate for smallpox in adults?
| children
10-20%
| 70%
118
where did the variolation technique originate
china, india, middle east
119
what type of filter was used that led to the discovery of viruses
chamberland porcelain ultrafilters
120
what did scientists landsteiner and popper do
| what year
1908
| try to determine the cause of polio eventually infected monkeys
121
what year was the hershey chase experiment
1952
122
when was the first pandemic and what was the disease
influenza
| 1918
123
constantly present at some level
endemic
124
sudden spike beyond expected levels
epidemic
125
worldwide epidemic
pandemic
126
what was the time frame for the polio epidemic
1916-1940
127
what year did the H1N1 epidemic occur
| what was the animal vector
2009
| pigs!
128
what are some key viral properties
```
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
where do the measles and smallpox virus start in the body? where do they move
what does it cause
start in the respiratory tract and then enters the blood and lymphatic system
lesions and rashes
130
where does rabies initially replicate and where does it move
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
where does the chickenpox virus start and where does it move
starts in the upper respiratory tract then moved to the spleen and liver and skin via the blood and lymphatic system
132
what type of cell is latently infected by chickenpox
neurons
133
t/f
| viruses can only be transmitted during birth
false! they can be transmitted during, before, and after birth
134
what 2 viruses can lead to neonatal death, stillbirth or spontaneous abortion
smallpox
| CMV
135
what 2 viruses can lead to congenital malformations
zika
| rubella (german measles)
136
is it possible to shed a virus if you are asymptomatic
yes!
137
t/f
| viruses typically prefer warm temperatures
false
| they are chilly bois
138
what are some non-protein coding sequences
introns
non-coding rna genes
promoters and enhancers
139
t/f
| dna replication is semi-conservative
true
140
how do you tell the 5' end from the 3' end of dna
5' has triphosphates
| 3' has a free OH
141
what is leaky scanning
when does it happen
what does it allow
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
what are four ways the capsid can be removed
degradation
transport to locations that cause stress
alter capsid proteins during attachment
during the fusion process
143
where do enveloped viruses tend to assemble
near the plasma membrane
144
number of cycles takes to amplify past the baseline fluorescence threshold
Ct
145
detects corona virus specific transcripts
qRT-PCR
146
what does qRT-PCR measure
| what does faster accumulation mean
the amount of viral RNA transcripts
| more viral RNA present
147
which genes does qRT-PCR look for
N gene
RdRp gene
E gene
148
what are the three stages of qRT-PCR and what temperatures do they occur at
how many times do you repeat these stages
denaturing: 95 C
annealing: 60 C
elongation: 70 C
40
149
what are the four steps to qRT-PCR
isolate rna
dnase rxn
reverse transcription
qPCR
150
what Ct value typically indicates a positive test for qRT-PCR
<35
151
immunoassay used to detect specific viral protein
antigen testing
152
what is the protein typically tested for when doing antigen testing
N protein
153
what does a positive antigen test look like
visible control and test line
154
t/f
| antigen testing has a higher sensitivity rate compared to qRT-PCR and less accurate
false
| has lower sensitivity but is more accurate
155
when is peak viral load seen in COVID patients
onset of symptoms or 1st week
156
is receptor mediated endocytosis pH independent or dependent
pH dependent
157
is receptor mediated signaling pH independent or dependent
independent
