microbiology ch 13 Flashcards
1
Q
These are obligatory intracellular parasites that require living host cells to multiply
A
Viruses
2
Q
Do viruses have a single type of nucleic acid, either DNA or RNA?
A
Yes
3
Q
Do viruses have a protein coat?
A
Yes
4
Q
Do viruses have ribosomes
A
No
5
Q
Do viruses have ATP-generating mechanisms?
A
No
6
Q
What is a virus’ host range?
A
The spectrum of host cells a virus can infect
7
Q
Can most viruses infect every type of cell in a host?
A
No
8
Q
What determines what cells viruses infect?
A
Specific host attachment sites and cellular factors
9
Q
What are bacteriophages?
A
Viruses that infect bacteria
10
Q
What is the range of virus size?
A
20 nm to 1000 nm
11
Q
This is the spectrum of host cells a virus can infect
A
Host range
12
Q
These are viruses that infect bacteria
A
Bacteriophages
13
Q
What is a virion?
A
A complete, fully developed viral particle
14
Q
What is a capsid?
A
A protein coat made of capsomere subunits
15
Q
What is a viral envelope?
A
Lipid, protein, and carbohydrate coating on some viruses
16
Q
This is a complete, fully developed viral particle
A
Virion
17
Q
This is a protein coat made of capsomere subunits
A
Capsid
18
Q
This is a lipid, protein, and carbohydrate coating on some viruses
A
Envelope
19
Q
These are projections on the outer surface of a virus
A
Spikes
20
Q
What shape are helical viruses?
A
Hollow and cylindrical
21
Q
What shape are polyhedral viruses?
A
Many-sided, icosahedrons
22
Q
What shapes are enveloped viruses?
A
Helical or polyhedral
23
Q
What shape are complex viruses?
A
Complicated structures
24
Q
These viruses are hollow and have a cylindrical capsid
A
Helical viruses
25
These viruses are many-sided icosahedrons
Polyhedral viruses
26
These viruses can be helical or polyhedral
Enveloped viruses
27
These viruses have complicated structures
Complex viruses
28
What do virus genus names end with?
-virus
29
What do virus family names end with?
-viridae
30
What do virus order names end with?
-ales
31
What is a viral species?
Group of viruses sharing the same genetic information and ecological niche (host range)
32
What type of names are used for virus species?
Descriptive common names
33
How are virus subspecies designated?
By a number
34
This taxonomic level of viruses ends in -virus
Genus
35
This taxonomic level of viruses ends in -viridae
Family
36
This taxonomic level of viruses ends in -ales
Order
37
This is a group of viruses sharing the same genetic information and ecological niche (host range)
Viral species
38
Descriptive common names are used for this taxonomic level of viruses
Species
39
These viruses are designated by a number
Subspecies
40
Must viruses be grown in living cells?
Yes
41
What are bacteriophages grown in?
Bacteria
42
What are plaques?
Clearings in bacteria on surface of agar
43
What is another term for plaques?
Plaque-forming units (PFU)
44
These must be grown in living cells
Viruses
45
These viruses are grown in bacteria
Bacteriophages
46
These are clearings on a lawn of bacteria on the surface of agar formed by bacteriophages
Plaques
47
These are also known as plaque-forming units
Plaques
48
Does each plaque correspond to a single virus?
Yes
49
What is the cytopathic effect (CPE)?
Deterioration of virally infected cells in culture
50
What are tissues treated with to separate cells in bacteriophage cultures?
Enzymes
51
How are virally infected cells detected?
Via their deterioration, or cytopathic effect (CPE)
52
What type of serological test can be done to identify viruses?
Western blotting reaction of the virus with antibodies
53
What 2 tests can be done to identify viruses using their nucleic acids?
Restriction Fragment Length Polymorphism (RFLP) and polymerase chain reaction (PCR)
54
What two things must happen for a virus to multiply?
It must invade a cell host and take over the host's metabolic machinery
55
What type of growth curve does viral multiplication show?
One-step growth curve
56
What is the early period in viral multiplication when growth is hidden and cannot be measured?
Eclipse period
57
What happens during the lytic cycle?
Phage causes lysis and death of the host cell
58
What 3 things happen during the lysogenic cycle?
Phage DNA is incorporated in the host DNA; phage conversion; specialized transduction
59
In this cycle, the phage causes lysis and death of the host cell
Lytic cycle
60
In this cycle, phage DNA is incorporated in the host DNA, and there is phage conversion and specialized transduction
Lysogenic cycle
61
What type of bacteriophages undergo the lytic cycle only?
Virulent bacteriophages
62
What type of bacteriophages can undergo both the lytic and lysogenic cycles?
Temperate bacteriophages
63
What happens during the attachment phase of the lytic cycle?
The phage attaches by the tail fibers to the host cell
64
What happens during the penetration phase of the lytic cycle?
The phage lysozyme opens the cell wall and the tail sheath contracts to force the tail core and DNA into the cell
65
What happens during the biosynthesis phase of the lytic cycle?
Production of phage DNA and proteins
66
What happens during the maturation phase of the lytic cycle?
Assembly of phage particles
67
What happens during the release phase of the lytic cycle?
Phage lysozyme breaks the cell wall and assembled phages leave to infect other host cells
68
During this phase of the lytic cycle, the phage attaches to the host cell by the tail fibers
Attachment
69
During this phase of the lytic cycle, the phage's lysozyme opens the cell wall, and its tail sheath contracts to force the tail core and DNA into the cell
Penetration
70
During this phase of the lytic cycle, phage DNA and proteins are produced
Biosynthesis
71
During this phase of the lytic cycle, the phage lysozyme breaks the cell wall and assembled phages may go on to infect other host cells
Release
72
During this phase of the lytic cycle, viral components are assembled into virions
Maturation
73
What happens during lysogeny?
Phage remains latent
74
What is a prophage?
Inserted phage DNA
75
What happens when the host cell replicates its chromosome?
Prophage DNA is also replicated
76
What happens as a result of phage conversion?
The host cell exhibits new properties
77
What 2 things happen in specialized transduction?
Specific bacterial genes are transferred to another bacterium via a phage, and the genetic properties of the bacteria are changed
78
In this type of transduction, specific bacterial genes are transferred to another bacterium via a phage, changing the genetic properties of the bacteria
Specialized transduction
79
What happens during the attachment stage of animal virus multiplication?
Virus attaches to the cell membrane
80
What happens during the entry stage of animal virus multiplication?
Receptor-mediated endocytosis or fusion allows entry of the virus
81
What happens during the uncoating stage of animal virus multiplication?
Viral or host enzymes remove capsid proteins
82
What happens during the biosynthesis stage of animal virus multiplication?
Nucleic acids and proteins produced
83
What happens during the maturation stage of animal virus multiplication?
Nucleic acid and capsid proteins assemble
84
What happens to enveloped viruses during the release stage of animal virus multiplication?
Enveloped viruses bud out from cell membrane
85
What happens to nonenveloped viruses during the release stage of animal virus multiplication?
Nonenveloped viruses rupture plasma membrane
86
During this stage of animal virus multiplication, the virus uses plasma membrane proteins/glycoproteins to connect to plasma membrane
Attachment
87
During this stage of animal virus multiplication, the capsid goes inside the cell via receptor-mediated endocytosis or fusion
Entry
88
During this stage of animal virus multiplication, capsid proteins are removed enzymatically
Uncoating
89
During this stage of animal virus multiplication, nucleic acids and proteins are produced
Biosynthesis
90
During this stage of animal virus multiplication, nucleic acids and capsid proteins are assembled
Maturation
91
During this stage of animal virus multiplication, enveloped viruses will bud out, while nonenveloped viruses will rupture plasma membrane
Release
92
Where do DNA viruses replicate their DNA in the host cell?
Nucleus
93
Where do DNA viruses synthesize capsid in the host cell?
Cytoplasm
94
What do DNA viruses use to replicate their DNA in the nucleus of the host?
Viral enzymes
95
What are two diseases caused by Adenoviridae?
Respiratory infections (in humans), and tumors (in animals)
96
What does Poxviridae cause?
Skin lesions
97
What are two examples of viral groups in Poxviridae?
Vaccinia and smallpox viruses
98
These are nonenveloped, double-stranded DNA viruses that cause respiratory infections in humans and tumors in animals
Adenoviridae
99
These are enveloped, double-stranded DNA viruses that cause skin lesions
Poxviridae
100
What do HHV-1 and HHV-2-Simplexvirus cause?
Cold sores
101
What does HHV-3-Varicellovirus cause?
Chickenpox
102
What does HHV-4-Lymphocryptovirus cause?
Mononucleosis
103
What group of viruses does HHV-5-Cytomegalovirus and HHV-6 and HHV-7-Roseolovirus belong to?
Herpesviridae
104
What does HHV-8-Rhadinovirus cause?
Kaposi's sarcoma
105
These are enveloped, double-stranded DNA viruses that cause skin conditions and cancers
Herpesviridae
106
These viruses cause cold sores
HHV-1 and HHV-2-Simplexvirus
107
This virus causes chickenpox
HHV-3-Varicellovirus
108
This virus causes mononucleosis
HHV-4-Lymphocryptovirus
109
This virus causes Kaposi's sarcoma
HHV-8-Rhadinovirus
110
What does Papillomavirus cause?
Warts, cancer
111
This group of nonenveloped, double-stranded DNA viruses includes Papillomavirus, which causes warts and can transform cells to cause cancer
Papovaviridae
112
What group does the Hepatitis B virus belong to?
Hepadnaviridae
113
This group of enveloped, double-stranded DNA viruses includes the Hepatitis B virus and can use reverse transcriptase to make DNA from RNA
Hepadnaviridae
114
What enzyme do RNA viruses use to multiply in the host cell's cytoplasm?
RNA-dependent RNA polymerase
115
This type of viral RNA can directly serve as mRNA for protein synthesis
ssRNA + (sense) strand
116
This type of viral RNA must be transcribed to a + strand to serve as mRNA for protein synthesis
ssRNA - (antisense) strand
117
What is dsRNA?
Double-stranded RNA
118
What does the Rhinovirus cause?
Common cold
119
This group of nonenveloped, single-stranded RNA, + strand viruses includes the Enterovirus, Rhinovirus, and Hepatitis A virus
Picornaviridae
120
What are two enteroviruses?
Poliovirus and Coxsackievirus
121
What transmit Alphavirus?
Arthropods
122
What does the Rubivirus cause?
Rubella
123
This group of enveloped, single-stranded RNA, + strand viruses include Alphavirus and Rubivirus
Togaviridae
124
What does the Lyssavirus cause?
Rabies
125
This group of enveloped, single-stranded RNA, - strand viruses includes the Lyssavirus and causes numerous animal diseases
Rhabdoviridae
126
What is another name for the respiratory enteric orphan virus?
Reovirus
127
What 2 conditions does the Rotavirus cause?
Mild respiratory infections and gastroenteritis
128
This group of nonenveloped, double-stranded RNA viruses includes the Reovirus and Rotavirus
Reoviridae
129
What do single-stranded RNA viruses use to produce viral DNA?
Reverse transcriptase
130
What does viral DNA do to the host chromosome?
Integrate into it as a provirus
131
What two types of viruses are included in Retroviridae?
Lentivirus (HIV) and Oncoviruses
132
These viruses use reverse transcriptase to produce DNA from the viral genome
Single-stranded RNA viruses
133
How is a provirus formed?
When viral DNA integrates into the host chromosome
134
This group of viruses includes Lentivirus and Oncoviruses
Retroviridae
135
Are cancers caused by viruses contagious?
No
136
What are the two main types of solid tumors?
Sarcoma and adenocarcinoma
137
What do oncolytic viruses do?
Selectively infect and kill tumor cells
138
What kind of tissue does sarcoma affect?
Connective tissue
139
What kind of tissue do adenocarcinomas affect?
Glandular epithelial tissue
140
These viruses selectively infect and kill tumor cells
Oncolytic viruses
141
What do oncogenes do?
Transform normal cells into cancerous cells
142
What do oncogenic viruses (oncoviruses) do?
Become integrated into the host cell's DNA and induce tumors
143
What is the percentage of cancers known to be virus-induced?
10%
144
Where does a transformed cell harbor a tumor-specific transplantation antigen (TSTA)?
On the surface
145
Where does a transformed cell harbor a T antigen?
In the nucleus
146
These transform normal cells into cancerous cells
Oncogenes
147
These become integrated into the host cell's DNA and induce tumors
Oncogenic viruses (oncoviruses)
148
A transformed cell harbors this on its surface
Tumor-specific transplantation antigen (TSTA)
149
A transformed cell harbors this in the nucleus
T antigen
150
This group of viruses uses reverse transcriptase and includes human T-cell lymphotrophic virus-1 and -2, as well as the hepatitis C virus
Retroviridae
151
What do human t-cell lymphotrophic virus-1 (HTLV-1) and -2 (HTLV-2) cause?
Adult T cell leukemia and lymphoma
152
What does a latent virus do?
Remains in an asymptomatic host cell for long periods
153
What causes a latent virus to reactivate?
Changes in immunity
154
What are two examples of conditions caused by latent viruses?
Cold sores and shingles
155
What does a persistent viral infection do?
Occurs gradually over a long period
156
Are persistent viral infections generally fatal?
Yes
157
This type of virus remains in an asymptomatic host cell for long periods, and may reactivate due to changes in immunity
Latent virus
158
This type of viral infection occurs gradually over a long period and is generally fatal
Persistent viral infection
159
How are two ways plant viruses enter cells?
Through wounds or insects
160
Is it easier for viruses to enter plant cells than animal cells?
No
161
What are viroids?
Short pieces of naked RNA
162
What is an example of a plant disease caused by viroids?
Potato spindle tuber disease
163
What are virusoids?
Viroids enclosed in a protein coat
164
When are virusoids able to cause disease in a plant?
When plant cell is coinfected with a virus
165
This generally protects plant cells from viruses
Cell wall
166
These are short pieces of naked RNA, and are the cause of potato spindle tuber disease
Viroids
167
These are viroids enclosed in a protein coat and only cause disease when a plant cell is coinfected with a virus
Virusoids
