Fundamentals of Virology Flashcards
1
Q
What was seen in Egyptian mummies in 3700 BC?
A
Poliomyelitis
2
Q
What did Pharaoh Ramesses V succumb to in 1196 BC?
A
Smallpox
3
Q
Edward Jenner inoculated James Phipps with what in 1796 to test vaccination against small pox?
A
Cowpox
4
Q
What year did Louis Pasteur prove the Germ Theory of Disease?
A
1860
5
Q
What year did Robert Koch publish his postulates on the cause of disease?
A
1890
6
Q
Who demonstrated Koch’s postulates in 1892 based on a filterable substance present on the sap of tobacco with mosaic disease?
A
Dmitri Ivanovsky
7
Q
Who independently replicated Dmitri Ivanovsky’s experiemnts in 1898?
A
Martinus Beijerinck
8
Q
Who discovered the cause of what in 1898? Include viral agent.
A
Freidrich Loeffler; Foot-and-mouth disease; Aphthovirus
9
Q
Who discovered that yellow fever is transmitted by a particular mosquito species in 1900?
A
Walter Reed
10
Q
Who are the two scientists that discovered the causative agent of poliomyelitis?
A
Karl Landsteiner and Erwin Popper
11
Q
What did Frederick Twort discover in 1915?
A
Bacteriophages
12
Q
Who discovered phage therapy in 1917?
A
Felix d’Herelle
13
Q
What did Max Theiler develop against yellow fever in 1937?
A
Attenuated 17D Strain Vaccine
14
Q
What are the two phases in the life cycle of a virus?
A
Transmission and Reproduction
15
Q
What do you call a fully developed, infectious viral particle made up of nucleic acid and a protein coat?
A
Virion
16
Q
What is the simplest virion?
A
Nucleocapsid (e.g. Picornaviridae)
17
Q
What are the structural units of the capsid?
A
Capsomeres
18
Q
What are the glycoprotein projections on the surface of the viral envelope?
A
Peplomers
19
Q
Describe the nomenclature system for viruses.
A
Order = -virales
Family = -viridae
Subfamily = -virinae
Genus = -virus
20
Q
What are the bases of virus classification?
A
- Symmetry of nucleocapsid
- Presence or absence of an envelope
- Type of nucleic acid
- Polarity of the viral genome
21
Q
What is a feature of the viral capsid in relation to drugs?
A
Allows small antiviral drugs like azidothymidine to enter
22
Q
What are the two types of viral capsid?
A
Helical and icosahedral
23
Q
Features of helical symmetry
A
- Capsid length is determined by nucleic acid size
- Capsomeres are bagel-shaped
- All possess an RNA genome
- Allows for a flexible nucleocapsid
24
Q
Features of icosahedral symmetry
A
- Has 20 faces and 12 vertices
- May have appendages at each vertex
- Found in DNA viruses except Pox Virus
25
Example of an enveloped helical virus
Influenzavirus
26
Example of a non-enveloped polyhedral/icosahedral virus
Mastadenovirus
27
Describe the structure of poxviruses.
Brick-shaped with ridges on external surface and a core and lateral bodies inside
28
Notable characteristics of the viral envelope
1. Susceptible to acids and lipid solvents
2. Difficult to crystalize
3. Disables viruses from infecting GI tract (due to bile)
4. Makes virus less stable than non-enveloped counterparts
5. May form multinucleated cells
29
Notable characteristics of naked viruses
1. Easy to spread
2. Protein capsid generally more stable in harsh conditions
3. Icosahedral symmetry
4. Exit host cell via lysis
5. Includes common GI viruses
30
Naked RNA viruses
1. Caliciviridae
2. Picornaviridae
3. Reoviridae
31
Naked DNA viruses
1. Adenoviridae
2. Papovaviridae
3. Parvoviridae
32
What do dsRNA viruses mostly infect?
Fungi
33
What do ssRNA viruses mostly infect?
Plants
34
What virus family has a large RNA genome?
Coronavirus
35
What does a segmented virus genome provide?
Possibility of new gene combinations and, thus, rapid evolution
36
Types of terminal repeats
Direct and Inverted
37
What is the only single stranded DNA virus family?
Parvoviridae
38
What is the only non-enveloped DNA virus family?
Parvoviridae
39
What is the only virus family with a complex envelope?
Poxviridae
40
These virus families have dsDNA and are enveloped
1. Hepadnaviridae
2. Herpesviridae
41
These are non-enveloped virus families with circular DNA
1. Papillomaviridae
2. Polyomaviridae
42
This is a non-enveloped virus family with linear DNA
Adenoviridae
43
Which virus family does not replicate in the nucleus?
Poxviridae
44
What are the virus families with a DNA genome?
1. Adenoviridae
2. Hepadnaviridae
3. Herpesviridae
4. Parvoviridae
5. Poxviridae
6. Papovaviridae
1A, 2Hs, and 3Ps
45
What hepatitis virus has a DNA genome?
Hepatitis B
46
How many adenoviruses are there?
Fifty-two
47
What do members of Adenoviridae cause?
Respiratory infections, conjunctivitis and GIT infection
NOTE: Types 41 & 42 cannot be cultured.
48
What do members of Parvoviridae cause?
Fifth disease or erythema infectiosum
B19 is characteristic in children.
49
Enumerate members of Papovaviridae
1. Papilloma virus
2. Polyoma virus
3. Vacuolating viruses
50
What is the biggest virus family?
Poxviridae
51
Enumerate members of Poxviridae
1. Variola virus
2. Vaccinia virus
3. *Molluscum contagiosum*
52
Why don't Poxviridae viruses need to replicate in the nucleus?
They carry their own enzymes
NOTE: They still need the ribosomes in the cytoplasm.
53
Which genus causes smallpox?
*Variola*
54
Which genus was used to carry the vaccine for smallpox?
*Vaccinia*
55
Which is the only double stranded RNA virus family? Are they enveloped?
Reoviridae; No
56
Which RNA virus families have icosahedral symmetry?
1. Picornaviridae
2. Reoviridae
3. Retroviridae
4. Flaviviridae
5. Caliciviridae
6. Togaviridae
PRRFCT!
57
Which RNA virus families have helical symmetry?
1. Coronaviridae
2. Rhabdoviridae
3. Arenaviridae
4. Paramyxoviridae
5. Bunyaviridae
6. Filoviridae
7. Orthomyxoviridae
CRAP, may BF-O!
58
Which RNA virus families do not replicate in the cytoplasm?
Retroviridae and Orthomyxoviridae
59
What do RNA viruses need for replication?
RNA-dependent RNA polymerases
60
Segmented genome occurs in which viruses?
RNA viruses
61
Which virus families have a segmented genome?
1. Bunyaviridae
2. Orthomyxoviridae
3. Reoviridae
4. Arenaviridae
BORA!
62
Examples of viruses under Bunyaviridae
1. Rotta virus
2. Rift Valley virus
3. Sin Nombre virus
4. Hantaan virus
63
Which non-hemorrhagic Philippine virus found in pigs falls under Bunyaviridae?
Ebola reston
64
Examples of viruses under Arenaviridae
1. Lassa virus
2. Lymphocytic choriomeningitis virus
65
Examples of viruses under Togaviridae
1. Rubella
2. Chikungunya
3. Equine encephalitis viruses
66
Which common RNA virus is capable of antigenic shift?
Influenza A
67
Examples of viruses under Orthomyxoviridae
Influenza viruses
68
Examples of viruses under Flaviviridae
1. Yellow fever virus
2. Dengue virus
3. Japanese encephalitis virus
4. West Nile virus
5. Hepatitis C virus
69
In ELISA, what antibody should be targeted for higher specificity in distinguishing Japanese encephalitis and Dengue?
IgM
70
Examples of viruses under Filoviridae
Ebola viruses
71
Examples of viruses under Picornaviridae
1. Polio virus
2. Coxsackie virus
3. Echo virus
4. Hepatitis A virus
5. Rhinovirus
6. Foot and Mouth virus
72
Examples of viruses under Paramyxoviridae
1. Parainfluenza viruses 1 - 4
2. Measles virus
3. Mumps virus
4. RSV
73
Examples of viruses under Retroviridae
1. Human T-lymphotropic Virus (HTLV)
2. HIV
74
Examples of viruses under Reoviridae
Rotaviruses (common in GI tract)
75
Examples of viruses under Rhabdoviridae
1. Rabies virus
2. Vesicular stomatitis
76
Examples of viruses under Coronaviridae
SARS virus
77
Examples of viruses under Caliciviridae
1. Noroviruses (infects GI tract)
2. Hepatitis E
78
Which viruses are pleiomorphic?
Filoviridae and Paramyxoviridae
79
How long does the eclipse phase of viral growth usually last?
10 - 12 hours
80
What are the stages of virus replication in animals?
1. Adsorption
2. Penetration
3. Uncoating
4. Duplication/Synthesis
5. Assembly
6. Release
81
What surface receptor do viruses normally latch onto?
Glycoproteins (i.e. G120 protein)
82
Differentiate penetration via endocytosis, translocation and fusion
Fusion = Enveloped
Translocation = Naked
Endocytosis = Both
83
Where can uncoating of viruses occur?
ER (sometimes)
84
Why is fusion of the virus with the host cell possible?
Because viral envelope is derived from the host, so membrane properties are quite similar
85
What do polyviruses do when penetrating the host cell?
Passive transfer of nucleic acid
86
Describe the Baltimore Classification of VIruses
I - dsDNA viruses
II - ssDNA viruses
III - dsRNA viruses
IV - ssRNA viruses, (+) sense
V - ssRNA viruses, (-) sense
VI - "diploid" ssRNA viruses w/ dsDNA intermediate
VII - dsDNA viruses w/ ssRNA intermediate
87
What are examples of positive sense ssRNA viruses?
Polio virus and Hepatitis A virus
88
What are the products of class IVa and IVb viruses?
IVa - polyproteins
IVb - subgenomic proteins
89
What is the exception for class V viruses?
Ortho (or influenza viruses) that have capping as the intermediate nuclear step
90
What do class V viruses bring with them?
RNA-dependent RNA polymerases
91
What are the three enzymes utilized by Retroviridae in reverse transcription?
1. Reverse transcriptase
2. Integrase
3. Protease
92
How is dsDNA synthesized in class VII viruses?
(+) strand - mRNA
(-) strand - reverse transcriptase
93
How is dsDNA replicated in viruses?
Virus uses host's DNA-dependent RNA polymerase to produce RNA-dependent RNA polymerase, which is transported into the nucleus from the cytoplasm.
94
Which viruses must synthesize their own DNA-dependent DNA polymerase?
1. Adenovirus
2. Herpesvirus
3. Poxvirus
95
Examples of dsRNA viruses
Rotavirus and Colorado Tick Fever Virus
96
Mechanism of RNA replication in dsRNA viruses
Parent RNA -\> Transcriptase -\> Positive mRNA -\> Negative mRNA
97
Replication is _________ in dsRNA viruses
Conservative
98
Reverse transcriptase is also known as...
RNA-dependent DNA polymerase
99
In latent RNA viruses, what happens to the replicated DNA?
It may embed itself in the host genome and remain latent.
100
What are the two main stages of virion release?
Budding and Lysis
101
Which viruses exhibit lysis as their mechanism of releasing newly produced virions?
Naked and complex viruses
102
Which viruses exhibit budding or exocytosis as their mechanism of releasing newly produced virions?
Enveloped viruses
103
Majority of antiviral drugs are for what family of viruses?
Herpesviridae
104
Which virus is self-limiting and produces paralysis in only 1 - 2% of the affected population?
Polio virus
105
