Chapter 1 Flashcards
(83 cards)
1
Q
who is the father of virology?
A
dimitri ivanovsky
2
Q
Dimitri Ivanovsky did what?
A
- Russian biologist (botanist)
- Reported that the infectious component of tobacco mosaic disease could pass through a porcelain filter that removed bacteria and fungi (1892)
- “filter-passing”
- Did not isolate a virus particle
3
Q
who is martinus Beijerinck?
A
- Dutch microbiologist and botanist
infectious agent could replicate in plants, therefore not a toxin (1898) - Used the term
- Contagium vivum fluidim (infectious living liquid) to describe his findings
4
Q
who was Ernst Ruska?
A
- german physicist
- visualization of viruses didn’t occur till 1930s with the microscopy advent of electron microscopes
5
Q
how did yellow fever originate?
A
from africa, spread to the new world with slave trade
6
Q
what was the first human disease whose causative agent was identified as a virus?
A
yellow fever
7
Q
Jesse William Lazear preformed what two tests?
A
- Volunteers slept in clothes and beds of yellow fever patients (but had mosquito nets) (did not get sick)
- Volunteers stayed away from patients but were exposed to mosquitoes that fed on yellow fever patients
(all got sick)
8
Q
yellow fever was spread by?
A
insect vector
9
Q
you need____ and ___ cells to culture viruses
A
live and replicating
10
Q
what is a virus?
A
- A subcellular ‘organism’ with a parasitic life cycle
- Needs a host cell to replicate
- Has no metabolic activity outside of the host cell
11
Q
a virus’s infection may be lytic or latent meaning?
A
lytic (causing cell death)
latent (viral genome remains dormant in host cell)
12
Q
oncogenic
A
cancer causing
13
Q
what are the abilities that prove viruses to be alive
A
- Ability to replicate
- Evolve
- Contain nucleic acids
14
Q
what are the abilities that prove viruses not to be alive
A
- Energy production
- Respiration
- Response to negative environments
- Locomotion
- Growth
15
Q
virus particles bind to ____ cells
A
target
16
Q
viral genome replicates _____ the cell
A
within
17
Q
what is the viron?
A
- virus particle, a single infectious agent
- Made of nucleic acid genome (DNA or RNA) protected by a protein shell
18
Q
what is the capsid?
A
protein structure surrounding viral genome
19
Q
Capsomers
A
repeating protein subunits that form the capsid
20
Q
envelope
A
derived from host cell lipid bilayer, covers virus capsid
21
Q
Nucleoproteins
A
proteins that surround the viral genome (either structural or replicative proteins)
22
Q
Nucleocapsid
A
nucleic acids, structural, and replicative proteins
23
Q
what is a tegument?
A
Thick group of proteins underneath envelope
24
Q
enveloped virus:
A
- RNA genome
- Nucleoproteins
- Nucleocapsid
- Capsid
- Envelope
- Glycoproteins
25
non enveloped virus:
- DNA genome
- Nucleoproteins
- Capsid
- Nucleocapsid
26
what are the 4 standard morphological groups?
1. non enveloped /helical capsid
2. non enveloped/ icosahedral capsid
3. enveloped/ helical capsid
4. enveloped/icosahedral capsid
27
How is the capsid formed?
repeating protein subunits (capsomers)
28
capsids arent capable of self assembly (T F)
false, they are
29
what is the morphology of capsids?
helical or complex
30
describe icosahedral symmetry
symmetry is based on the presence of the correct axes of symmetry
- 2 fold axes of rotational symmetry about the face edge
- 3 fold axes of rotational symmetry about the face centre
- 5 fold axes of rotational symmetry about the face vertex
31
what is the symmetry of picornovirus?
dodecahedron
32
what is the symmetry of adenovirus?
hexameric
33
the picornavirus is a __________ capsid protein
4 (VP1 VP2 VP3 VP4)
34
the adenovirus is made up of __________ hexon subunits
| and ____________ proteins in total
20, 11
35
the poxvirus has a very _______ genome and expresses more than 100 proteins
large
36
`the flivovirus has a ____ nucleocapsid
helical
37
when was the last outbreak of smallpox?
1997
38
*what did jesse lazear determine was the vector of yellow fever?
mosquitos
39
the virus envelope is derived from the __________ _________
host membrane
40
viral glycoproteins are ________
hydrophilic
41
lipids cannot be inserted into the envelope (T F)
false (they can)
42
lipids cannot be inserted into the envelope (T F)
false (they can)
43
the viral genome has eirther _____or _____
DNA or RNA but not both
44
can the viral genome be single or double stranded?
yes
45
viruses are the only known form of life that can have a genome made of RNA (T F)
T
46
the genome size is related to the ________ of the virus
complexity
47
____ has one of the largest genomes that can infect humans?
poxvirus
48
_________ has the smallest genome infecting humans
parvovirus
49
_________ has the smallest genome infecting humans
parvovirus
50
viruses use ________ to maximize functionality from limited genome sequence
frameshifting
51
each amino acid is encoded by 3 bases called a ____
codon
52
what is RNA splicing?
cut and joins viral mRNA to produce different proteins from one original RNA molecule
53
even in the largest virus genome _______ codes for proteins
90%
54
DNA viruses are replicated by _____ processes or _____ processes
cellular or simple
55
DNA viruses form replication centers in what 2 places?
cytoplasm or nucleus
56
what do host DNA polymerases do?
check the sequence
57
for RNA viruses replication usually involves _____ cell machinery
host
58
are RNA viruses proofread?
no
59
RNA viruses have a ______ mutation rate
high
60
RNA viruses have a _______ genome to decrease the mutation rate
segemnted
61
what is antigenic drift and which viruses use it?
RNA viruses use to confer immune escape advantage
62
*A larger genome means more complex virus ( T F)
T
63
HIV is one of the most rapidly ________ viruses
changing
64
is HIV segmented
non segmented
65
is HIV segmented
non segmented
66
HIV has a ____ genome
diploid
67
what are the 4 hypothesis for HIV mutation rates?
1. reverse transcriptase is a low fidelity polymerase, each genome copy will be different from its parental template
2. Reverse transcriptase jumping from one genome to the other could introduce errors
3. Multiple HIV particles infecting the same cell, genomes could reassort
4. Recombination during DNa integration and excision, recombination rate would be high
68
what is the result of HIV mutation rates?
incredible immune invasion capabilities
69
what is the result of HIV mutation rates?
incredible immune invasion capabilities
70
does every ifnection cause disease?
no
71
describe the effect infection causing disease?
mostly observed in viruses who have jumped to new host
| - some symptoms cause imune response, ex. ebola
72
what is asymptomatic ?
no symptoms or flare ups
| - latent HSV 1
73
what is asymptomatic ?
no symptoms or flare ups
| - latent HSV 1
74
describe how viruses modulate the host cell?
- take over protein synthesis machinery
- have mechanisms to maike host cell recognize viral mRNA
- control the immune response
75
what are the types of virus infection?
- transforming
- latent
- acute
- chronic
76
describe a lytic infection:
- cell lysis following production of viral particles
| - rapid cell death
77
what causes cell lysis?
- viral enzymes
- indirect damage of producing so many viral particles
- breakdown of membrane integrity
78
describe persistent or chronic infections:
Infections that produce small amounts of virus over a long period of time because the immune system doesnt recognize viral antigens
ex. hep B hep C
79
describe a latent infection
viral genome is present but not active within the cell, only a small portion of viral genome is active
80
there is __ RNA LAT involved in the reactivation of HSV 1
3
81
what is a provirus?
the genetic material of a virus is incorporated into and able to replicate as part of the genome of a host cell
82
what is oncogenesis?
- loss of regulation of cell growth
- Changes to cell appearance and structure
- Abnormal chromosome numbers (aneuploidy)
- Altered transcription and production of growth factors
- Uninhibited cell growth
83
what is retroviridae?
viruses can insert their genome into the hosts causing mutations
