Introduction to Viruses 2 Flashcards
(123 cards)
1
Q
vast majority of DNA viruses have
A
double stranded genome
2
Q
vast majority of RNA viruse have
A
single stranded genome
3
Q
parovirus is what kind of genome
A
single stranded DNA
4
Q
what is the only family that has single stranded DNA
A
parovirus
5
Q
where do DNA viruses replicate
A
where the majority of our DNA is: nucleus
6
Q
what is exception to DNA replication
A
Pox viruses - replicate in cytoplasm
7
Q
where do RNA viruses replicate
A
cytoplasm
8
Q
what is exception to RNA viruses replicate
A
orthomyxoviruses - replicates in nucleus
9
Q
what DNA families replicate in both nucleus and cytoplasm
A
retrovirus
hepadnavirus
10
Q
baltimore classification is classified based on
A
replication strategy
11
Q
ds DNA virus, how will it replicate?
A
nucleus
12
Q
exceptoin to route for DNA virus, how will it replicate?
A
poxvirus will replicate in the cytoplasm
13
Q
replication strategy for majority of double stranded DNA viruses
A
in nucleus
14
Q
in the nucleus the viral DNA genome is transcribed by
A
host RNA polymerase
15
Q
for large DNA viruses they will have what right away
A
immediate early and early gene products
16
Q
viral DNA polymerase - ds DNA
A
some viruses encode their own, host cells would only have it in S phase, they wouldn’t have sufficient to replicate their genome
17
Q
depending on cell virus affects it can utilize
A
host DNA polymerase
18
Q
for herpes virus they encode their own
A
viral DNA polymerase
19
Q
what needs to be packaged
A
enzymes that are required to get to mRNA stage
20
Q
regarding DNA polymerase, the virus just has to
A
encode it
21
Q
viral DNA polymerase will do what
A
replicate viral genome
22
Q
late proteins are
A
structural proteins of virus
23
Q
do DNA virus have to package DNA enzyme
A
no b/c the host cell can provide enzyme needed to get to mRNA
24
Q
what is exception to DNA replication
A
pox virus - they replicate in cytoplasm, so even though host cell has the enzyme needed to get to mRNA, it won’t be found in the cytoplasm, so they have to package RNA polymerase
25
pox virus has to package
RNA polymerase
26
RNA polymerase in pox virus is packaged
in virion itself
27
anything packaged also has to be
encoded
28
once there is mRNA what is made
early proteins
29
for pox viruses to replicate genome it has to encode
DNA polymerase
30
does pox virus package DNA polymerase
no - it is translated from first wave
31
list out steps of normal double stranded DNA proliferation
pg 33
32
list out steps of exception double stranded DNA replication
pg 34
33
once mRNA is made it can be translated
into any protein the Virus needs
34
single stranded DNA family are
paroviruses
35
exception to double stranded DNA
poxvirus
36
list steps for single stranded DNA viral replication
pg 36
37
once single stranded DNA is in host cell genome what happens
the host RNA polymerase will transcribe it
38
once mRNA of single stranded DNA is made it will
go to cytoplasm and make protein
39
paroviruses viruses infect what kind of cell
replicating cells
| erythrocytes
40
for ss DNA what will replicate the genome
host DNA polymerase will replicate genome
41
double stranded RNA virus family
riovirus (rotavirus is part of that family)
42
majority of rna virus replicate in
cytoplasm
43
ds RNA genome has to be transcribed into
mRNA
44
list steps of ds RNA replication
37
45
ds RNA has to package
RNA dependent RNA polymerase
46
the viral rna transcriptase used for ds RNA is
RNA dependent RNA polymerase
47
mRNA in ds RNA replication is translated into
proteins
48
mRNA is used to also make
viral RNA replicase
49
what is viral RNA replicase
RNA dependent RNA polymerase
50
new copies of genome are
encapsulated and released from the cell
51
positive sense RNA can be
directly translated into proteins
52
+ssRNA genome steps
pg 38
53
in +ssRNA does RNA dependent RNA polymerase need to be packaged
no
54
why doesn't +ssRNA need to package RNA dependent RNA polymerase
it's not needed to get to mRNA stage
55
-ssRNA virus what are examples
influenza, measles, rabies
56
influenza virus replicates in the
nucleus (this is exception!)
57
in influenz does the site of replication have anything to do with how it replicates
no b/c we don't have the rna dependent rna polymerase so it doesn't matter where it's replicated
58
list steps for -ssRNA replication
pg 39
59
in -ssRNA genome rna dependent rna polymerase
is packaged in virion
60
in replication cycle of -ssRNA there is intermediate called
replication form - ds RNA
61
complementary starnd to genome in -ssRNA is
mRNA
62
+sense RNA virus it can be
direclyt translated into proteins
63
-sense RNA virus
genome cannot be direclyt translated, need to make complementary strand
64
enzyme needed for -sense RNA
has to be packaged as part of the virus
65
HIV is what kind of virus
retrovirus
66
why is HIV not considered part of +sense?
although genome is +sense, it's not available for translation
67
list steps for +ssRNA with DNA intermediate
pg 41
68
reverse transcriptase
has three catalytic activities
69
what is first activity of reverse transcriptase
rna dependent DNA polymerase
| makes rna to make complimentary dna strand
70
second function of reverse transcriptase
dna dependent dna polymerase
| uses dna strand to make template to the strand
71
third function of reverse transcriptase
ribonuclease - degrades the rna strand
72
what happens at end of +ss RNA with DNA intermediate
stays in host cell nucleus, will not be transcribed unless cell is activated
73
what enzyme does HIV bring with it to process proteins into mature form
protease
74
viral proteins made in +ss RNA with DNA intermediate (HIV)
precurser proteins - have to be made into mature form
75
why is protease packaged (in viruses like HIV)
it is still working when virus is budding from cell
76
unless cell is activated, HIV will
be provirus in nculeus, will not be made or transcribed or infect new cells
77
HBV stands for
hepatitis B virus
78
partial dsDNA genome example
HBV
79
steps of partial dsDNA genome with RNA intermediate
pg 44
80
viral dna polymerase in HBV
reverse transcriptase
81
HBV uses what to make mRNA
host RNA polymerase
82
HBV has what kind of genome
Partially double-stranded DNA with RNA intermediate
83
why does HBV virus bring the enzyme with it
it doesn't need it, it could use host cell enzyme
reverse transcriptase is packaged and encoded is b/c its required for packaging genome (needs reverse transcriptase to package!)
84
look at chart on pg 48-49
look at virion for each and understand
85
depending on where virus assembles it determines where what are
inclusion bodies are
| inclusion bodies are deposits of protein falling out of solution b/c there's so much protein being made
86
virus that assemble in nucleus, what kind of inclusion bodies?
intranuclear inclusion bodies (herpes)
87
virus that assemble in cytoplasm there will be what kind of inclusion bodies
intracytoplasmid inclusion bodies
88
if there are inclusion bodies or not depends on what?
depends on level of protein production
89
naked viruses will do what for release
burst open cell
90
envelop virus will require what for release
envelope from membrane bound body in cell - almost always plasma membrane
91
when viruses are budding they will indictate where they will bud by doing what
inserting peplomers at that site
92
naked virus released by
lysis
93
envelop virus released by
budding
94
herpes virus aquires envelope in what process
2 step process
95
2 step process of herpes virus envelop aquirement
assembles in nucleus, when it buds out of nuclear membrane it aquires envelope from inner nuclear membrane. that envleop efuses with outer nuclear membrane and that first envelop eis lost. the final envelope is aquired by budding into the golgi and then continues to plasma membrane and outside of cell
96
secondary envelop of herpes virus aquired by
golgi
97
ex of segmented RNA genome
influenza virus (8 different segments)
98
what can happen w / segmented genomes
if a cell is infected with (ex: two strains of influenza A virus), it can mix and match its genomes
reassortment!
99
what is re-assortment used to do
used to generate influenza vaccines
100
virus 1 and virus 2 (types of influenza) the different influenza RNA gene segments can be (what is result)
reassorted b/w themselves, so there can be virus that have features of both 1 and 2
101
what would re-assortment be used for regarding vaccines
generate a live vaccine that is weakened (live attenuated vaccine)
102
if there virulent strain of flu, how would you make a vaccine to protect ppl against it
grow the vaccine up with a weakened strain of the flu in fertilized chick eggs and it will reassort its genome
at end select for virus that has weakened nature of the one strain but has antigens of the virulent strain
103
external proteins dictate what
tropoism of virus
104
another mixing that can happen b/w viruses besides reassortment?
mixing of surface proteins
105
describe what is mixed when viruses mix their surface proteins
peplomers of envelope virus
| or capsid proteins of naked virus
106
a cell that is affected with two different viruses may have altered
tropoism
107
what is ultimate result of a virus that mixes surface proteins
that virus that leaves could have different tropism and infect another type of cell. however, it will only affect the different cell once b/c its genome hasn't changed, so when it reproduces it will go back to what it could affect before
108
in mixing of surface proteins of two viruses, what is mixed regarding phenotype and genotype
changing of phenotype, genome doesn't change
109
laboratory diagnosis of viral disesase
detection of virus
direct detection of viral antigens
serological analysis
molecular analysis of genetic material
110
dhow is detection of virus usually done
culture of virus
| if virus has hemagglutin can detect certain properties
111
HAI
can be done for viruses that have hemagglutinin
112
determine amount of virus what assay used
viral plaque assay
113
viral plaque assay
grow cells that are susceptible to infection by virus of interest
prepare different dilutions of virus (b/c when starting off don't know how much you have)
incubate
virus infects cell
get cell lysis
sufficient cells lysed that you can see it
count plaques to know how much virus is there
114
basis of viral plaque assay
virus lysing the cell it infects
115
dilution factor is inverse of
dilution
116
everywhere a virus infects a cell the virus
will lead to cell death
117
area of cell death is called
plaque (viral plaque)
118
count number of plaques what will it tell you
tell you how much virus is there
119
to determine how much virus is there after you get the plaques, what do you do?
multiply number of plaques by dilution number
120
in plaque assay you always have to change the mL it was plated in to be
1 mL
121
for viral plaque assay you need to know number of plaques in
1 mL
122
five hours following infection with polio virus, what happens
all the proteins being made inside the cell are poliovirus proteins
the poliovirus hijacks the cell
123
live vaccine that is weakened is called
live attenuated vaccine
