Virology Introduction (Exam 2) Flashcards
1
Q
viral genome
A
released inside the cytoplasm of the host cell
2
Q
what are genomes made up of?
A
DNA or RNA; not both, either or. single stranded (ss) or double stranded (ds)
3
Q
what do viruses need to survive?
A
a living cell to latch onto and leverage
4
Q
virus
A
Consists of a single nucleic acid surrounded by a protein coat and capable of replication only within the living cells of bacteria, animals, or plants. “obligate intracellular parasite”
5
Q
capsid
A
protein coat that surrounds viral nucleic acid. repeating subunits -capsomeres. helical or icosahedral symmetry.
6
Q
nucleocapsid
A
protein nucleic acid complex
6
Q
viroids
A
smallest known autonomously replicating molecule
7
Q
prions
A
infectious protein molecules; contain no definable nucleic acid
8
Q
viridae
A
family
9
Q
virinae
A
subgroup
10
Q
virus
A
genus
11
Q
parvoviridae
A
family
12
Q
parvovirinae
A
subgroup
13
Q
parvovirus
A
genus
14
Q
erythrovirus
A
genus
15
Q
how are viruses classified?
A
they are grouped into families, subgroups, and genera
16
Q
how are viruses grouped?
A
grouped into families according to
1. nucleic acid (ds/ss RNA, ds/ss DNA)
2. morphology of virion
3. strategy of viral replication
17
Q
reverse transcription
A
retroviruses use RNA as a template to make DNA - used by HIV
18
Q
Non-enveloped DNA viruses
A
Parvovirus - ss DNA
Papovavirus - ds DNA
Adenovirus - ds DNA
Iridovirus - ds DNA
19
Q
Enveloped DNA viruses
A
Hepadnavirus - partially ds DNA
Poxvirus - ds DNA
Herpesvirus - ds DNA
20
Q
Non-enveloped RNA viruses
A
Picornavirus - ss RNA
Reovirus - ds RNA
21
Q
Enveloped RNA viruses
A
all ss RNA
Rhabdovirus
Togavirus
Orthomyxovirus
Coronavirus
Bunyavirus
Arenavirus
Retrovirus
Paramyxovirus
22
Q
Difference between nonenveloped and enveloped viruses
A
enveloped viruses have a coating and spikes; nonenveloped do not
23
Q
components of the virion structure
A
(outside going in)
spike projections
lipid envelope
protein capsid
virion associated polymerase
nucleic acid
24
virion morphology
simple structure
repetitive structure
high level of redundancy
25
virus replication
replicate within a host cell while utilizing the host cell's nucleic acids
26
steps of virus replication
1. virus attachment and entry
2. uncoating of virion
3. migration of genome nucleic acid to nucleus
4. transcription
5. genome replication
6. translation of virus mRNAs
7. virion assembly
8. release of new virus particles
27
viral life cycle
attachment
penetration
un-coating
multiplication
assembly
release
28
virus cultivation
complex and includes:
chicken egg culture
cell culture
animal inoculation
29
what causes sickness?
pathogens; viruses, bacteria, parasites
30
adenovirus
cause of common cold
31
poxviridae
smallpox, cowpox, monkeypox
32
herpesviridae
cold sores (HHV-1)
genital herpes (HHV-2)
chickenpox (HHV-3 or varicella zoster)
33
papovaviridae
papillomavirus -warts
34
hepadnaviridae
cause of Hepatitis B
35
piconaviridae
causes polio
36
togaviridae
west nile encephalitis
37
rhabdoviridae
rabies
38
reoviridae
cause respiratory and intestinal tract infections
39
retroviridae
HIV
40
what is a viruses inner core?
nucleic acid surrounded by protein coat known as an envelope
41
size range of viruses
20-250 nanometers (nm)
42
how to diagnosis viral infections?
1. clinical syndrome
2. specimen
3. methodologies
- antigen detection
- nucleic acid detection
- antibody detection
- microscopic: viral induced cytopathology
43
elements of interaction
viral stain
inoculum size
route of exposure
susceptibility of host (pre-existing immunity)
immune status/age of host
44
result of interaction
no infection
abortive infection
asymptomatic infection
symptomatic infection
45
abortive infection
you get infected, fight the infection, but there is not tract of you ever having the infection
46
latent infections
infection is followed by symptom-less period, then reactivation, particles not detected until reactivation, symptoms of reactivation and initial disease may differ.
47
chronic infections
can be detected at all times, disease maybe present or absent during extended times or may develop late.
48
latent infections example
herpes simplex viruses 1 and 2 (HSV1 and HSV2) and shingles (zoster, chicken pox). after initial infection, virus replicates in neurons in non-infectious state. Virus activated to produce new disease symptoms
49
chronic infections example
hepatitis B aka serum hepatitis
after initial infection with or without disease symptoms, infectious virus is released from host with no symptoms
50
slow infections
agent gradually increases in amount over long period of time; two groups of infectious agents cause this infection (retroviruses which include HIV, prions); similar to the lysogenic cycle of gamma-phage
51
what are viruses capable of?
infecting all forms of life like vertebrates, prokaryotes, fungi, algae
52
most abundant form of life?
viruses, however, bacteriophages are extremely abundant, estimated 10^31 tailed bacteriophages
53
are all viruses bad?
no silly goose!
54
bacteriophages
viruses that infect harmful bacteria; hold promise as antibiotics; particularly in antibiotic resistant bacteria, immune reaction to phages remains a serious obstacle
55
phages
disrupt or kill biofilms made by bacteria
56
what is in a constant war?
bacteria and bacteriophages (viruses that only infect bacteria)
57
what has bacteria evolved to do?
remember bacteriophages that have encountered in the past so that they can more quickly destroy them in the future; they save a small segment of the bacteriophage's DNA in their own genome
58
Process of inserting the bacteriophage DNA?
once docked, the bacteriophage will insert its genome into the bacteria/ using a family of defensive proteins called Cas, the bacteria will cut a small segment of the bacteriophage's DNA and insert it into its own genome at a specific spot called the CRISPR Locus
59
what leads to discovery of promoters for eukaryotic RNA polymerases?
study of small DNA
60
what leads to discovery of many cellular oncogenes?
study of cancer producing viruses
61
what was discovered from studying mRNA from DNA viruses?
RNA splicing
62
what was discovered from studying phages and DNA viral replication?
Understanding of cellular DNA replication
63
benefit of studying tumor viruses?
clearer understanding of cancer
64
what can viruses be engineered to do?
carry exogenous genes that can be inserted in host's genome; referred to as vector virus which holds therapeutic agents; remains an issue
65
viral vector gene therapy for sickle cell disease
collection of blood forming stem cells - stem cells corrected by beta globin gene transfer from viral vectors - transplantation of corrected stem cells back to pt
66
cultivation of host
viruses multiple only inside host cell; cultivated in the lab in cell culture or tissue culture
67
quantitation
TEM direct count
68
methods of studying viruses
cultivation of host and quantitation
69
measurement of viruses
plaque forming assay
hemagglutination assay
70
plaque forming assay
initially done with bacteriophages and bacteria
71
hemagglutination assay
rapid and convenient, highest dilution showing max agglutination is titer of the virus
72
transmission of viruses
respiratory (influenza a virus)
fecal-oral (enterovirus)
blood-borne (hep b virus)
sexually (hiv)
animal or insect vectors (rabies)
73
virus tissue tropism
targeting of the virus to specific tissue and cell types
74
CD4+
cells infected by HIVC
75
CD155
acts as the receptor for poliovirus
76
in vivo disease
cell destruction, virus-induced changes to gene expression, immuno-pathogenic disease
77
acute virus infections
localized to specific site of body, development of viraemia with widespread infection of tissues
78
epstein barr virus
burkitt's lymphoma
79
human papillomavirus
benign warts, cervical carcinoma
80
human t cell leukemia virus (HTLV-1)
leukemia
81
hepatitis c virus
liver carcinoma
82
virus induced tumors
virus infects uninfected cell, integrated into cellular genome, causes changes in expression resulting in uncontrolled cell multiplication and tumor formation
83
cytopathic effect (CPE)
structural changes in host cells that are caused by viral infection
84
what virus causes AIDS?
HIV-1
85
what virus causes cervical carcinoma?
HPV types 16, 18, 31
86
what virus causes chickenpox?
varicella virus
87
what virus causes coldstores?
herpes simplex virus type 1
88
what viruses cause common cold?
adenovirus, coronavirus, rhinoviruses
89
what viruses cause diarrhea?
norwalk virus, rotaviruses
90
what virus cause genital herpes?
herpes simplex virus type 2
91
what viruses cause hemorrhagic fevers?
dengue virus, ebola and marburg viruses, lassa fever virus
92
what viruses cause hepatitis?
hep A, B, C virus
93
what virus causes influenza?
influenza A and B virus
94
what virus causes measles?
measles virus
95
what viruses cause mononucleosis?
epstein-barr virus, cytomegalovirus
96
what virus causes mumps?
mumps virus
97
what virus causes poliomyelitis?
poliovirus types 1 2 and 3
98
what virus causes rabies encephalitis?
rabies virus
99
what virus causes Severe acute respiratory syndrome
SARS coronavirus
100
what virus causes smallpox?
variola virus
101
what virus causes warts?
human papillomavirus types 1, 2, 4
102
what virus causes yellow fever?
yellow fever virus
