Exam 5 - Virology 1 Flashcards
5
What type of parasite is a virus?
5
Viruses require ____ metabolic processes and ______ machinery.
5
Viruses are the smallest known _____ organism. They are _____ nm.
5
Viruses are an _______ encased in a protein shell.
5
What size are parvoviruses?
5
What size are poxviruses?
6
Who found that the Tobacco Mosaic disease could be transmitted with diseased plants ground up in water?
6
Who found that agent was capable of passing through filters that blocked bacteria (Chamberland filters)?
6
Who repeated Ivanovsky’s experiments but showed that agent could be diluted and regain its potency after growth in a new host?
7
What is the term for a single virus particle?
7
What is the term for a nucleic acid-protein assembly packaged within the virion that is a discrete substructure of the particle?
7
What is the term for a proteins hell surrounding the nucleic acid genome?
7
Capsids protect against variations in ___, ___, and ________ of the environment.
7
What is the term for the nucleic acid and surrounding protein shell?
7
What is the term for the viral protein layer associated with the virion membrane?
7
What is the term for the membrane surrounding the virus core?
8
What are the four types of viral RNA genomes?
8
What is a positive sense single-stranded RNA viral genome?
8
What is a negative sense single-stranded RNA viral genome?
8
What is Ambisense RNA?
8
What is segmented vs. non-segmented RNA?
8
What are reverse transcribing viruses?
9
What is an example of a segmented, negative sense ssRNA viral genome?
9
What is an example of a segmented dsRNA virus?
9
What is an example of a linear ssDNA virus?
What is an icosahedral viral structure?
10
Is a helical viral structure common? What about ovoid?
12
What is vital for transmission of a virus and its mechanism of infection?
12
What is the term for a host-cell derived lipid bilayer carrying viral glycoproteins that forms the outer layer of a virus particle?
12
What is a disadvantage of a viral envelope?
12
Do enveloped or non-enveloped viruses tend to be more stable?
12
How do most viruses acquire a membrane?
12
Viral envelope proteins are _____ targeted to the appropriate membrane.
14
What is the term for the cells, tissues, and species that a virus can productively infect?
14
The host range is an absolute measurement. What does this mean?
14
What two things determine host cell range?
14
What is the term for the capacity of a cell, tissue, or species to support virus replication?
14
What kind of measurement is viral susceptibility?
15
What are the 7 major steps for general virus replication?
16
Where do a majority of viral infections initiate?
16
What are 4 major sites for viral infection?
16
What are two non-epithelial sites where viral infections can occur?
18
What are three cellular targets / receptors for virion binding to host cells?
18
For virus binding, receptors may limit _____ AND _____.
19
What are two mechanisms of extracellular uptake?
20
During virus fusion and entry, what does receptor binding cause?
20
After fusion with the plasma membrane, what effect does pH change have on the envelope protein during endocytosis?
20
What are two mechanisms of penetration through the plasma membrane during virus entry?
21
Is viral uncoating a well understood process?
21
Viral uncoating is initiated by what two cellular signals?
21
Partial or complete viral uncoating can occur. What can partial uncoating be used in the formation of?
21
Uncoating may involve release of factors to initiate _____ and/or shut off ________.
22
Where does replication for RNA viruses typically occur?
22
What may replication in the cytoplasm for RNA viruses involve?
22
What are two roles of the specialized replication complexes for RNA viruses?
22
In replication of RNA viruses, there is replication of progeny genomic RNA molecules using viral _______.
22
Synthesis of viral proteins relies on ______.
23
RNA virus membrane replication complexes are a means to hide from the ______.
23
RNA virus membrane replication complexes are typically associated with the _____ or the ______.
25
What is the formula for genetic capacity?
25
RNA is _____. It has a maximum genome size of ______.
25
RNA viruses that do not enter the nucleus cannot utilize what?
25
Why is recognition of specific RNA viruses hard?
25
RNA viruses must usurp the _____ to synthesize viral proteins.
25
dsDNA is a huge signal for _____.
25
Packaging of RNA virus must be _____.
25
RNA structure provides specificity.
-Recruits _____
-Promotes _____
-_____ signals
26
What are 4 mechanisms that RNA viruses use to increase genetic capacity?
28
Where does DNA replication typically occur?
28
DNA virus replication may or may not use host machinery depending whether the virus carries a _____. _______ proteins are usually present.
28
Synthesis of viral proteins may be regulated ______ for DNA viruses. This relies on ______.
29
During what stage of mitosis is DNA synthesis the most efficient? Why is this?
29
What is an example of a DNA virus that is limited to infecting mitotically active cells?
29
What is an example of a DNA virus that drives cellular proliferation?
29
Some DNA viruses inhibit ______.
29
What are two viruses that inhibit cellular DNA synthesis?
30
In assembly, the genome is typically incorporated as the ____ is assembled.
30
RNA viruses are assembled in the _____ while DNA viruses are assembled in the ______.
30
Where does assembly of enveloped viruses typically occur?
31
What are the 3 general steps of budding/release in replication?
31
What two things are happening in the lytic step of budding/release during replication?
32
HIV and many other viruses usurp the _______ vesicular budding pathway.
33
When does HIV maturation occur? Is the signal known or unknown?
33
What are three viruses that are limited to human only?
33
What are arboviruses transmitted by?
33
Humans are typically ______ of arboviruses.
36
Viral infectiom begins at the _____ and primary infection. Some viruses replicate locally and others enter the circulation and infect other tissues. This is known as ______.
36
It is likely that the majority of virus infections cause _____.
36
Resolution of Infection: The combined action of ____, ____, and _____ frequently results in lifelong immunity.
37
What are three things that the route of transmission of viruses depends on?
38
What is an example of a non-enveloped virus?
38
Enveloped viruses must remain ____.
38
Most enveloped viruses are labile to ____ and ______.
39
What are three environmental factors that affect transmission?
41
What is the percentage for the asymptomatic carrier population for the flu?
42
The adaptive immune response may _____ or ______ clinical disease.
42
Viremia, which is the spread to secondary target tissue, may produce _______. There will be initial acute signs, apparent recovery, and then secondary disease.
43
What are two examples of acute infections that may resolve due to immunity or natural course in a few days to weeks?
43
What are the two types of persistent infections?
43
Are latent infections detectable in tissue samples?
43
Are chronic viral infections detectable in tissue samples?
44
What are 4 examples of viruses that can result in oncolytic transformation of cells?
44
How does viral infection affect cell growth and survival and tolerance for DNA mutation?
44
What are two reasons why viral infection promotes cell growth and increases the tolerance for DNA mutations?
45
What are two things serological tests are used for?
45
What are two examples of serological tests?
45
What do PCR or RT-PCR tests detect?
45
What do PCR tests use to detect viral genomes?
46
What are the best targets of treatment for viral diseases?
46
What are three examples of unique viral enzymes that are targets of viral treatment?
46
What are 3 immune modulating drugs used in the treatment of viral diseases?
46
Besides immuen modulating drugs, what are two other forms of treatment for viral diseases?
47
Vaccines typically do not completely block infection, but they prevent disease by:
- ______
- ______
- _______
48
What are three types of vaccines?
48
Are prophylactic vaccines active or passive?
48
Are post exposure vaccines active or passive?
48
Are therapeutic vaccines active or passive?
48
What do therapeutic vaccines do?
49
Whole killed particles (inactive), empty virus-like particles (no nucleic acid), and su-virion, subunit, or individual antigens/proteins have _____ only.
49
Live-attenuated vaccines product __________ immunity to multiple targets.
49
mRNA vaccines are delivered via _____.
49
mRNA vacciens produce _______ immunity.
49
Do mRNA vaccines have a single or multiple targets?
49
What do viral vectors use to express antigenic proteins of pathogenic virus?
49
Viral vectors produce _________ immunity.
