Viral Characteristics and Vaccines Flashcards
1
Q
viruses: most common ____ of humans
A
infections
2
Q
viruses: obligate _____
A
intracellular parasites
3
Q
virion structure
A
- nucleic acid (RNA or DNA)
- capsid (structural shell/coat)
- plasma membrane* (stolen from the host)
4
Q
virus classification
A
- structure of viral capsule (capsid)
- genetic makeup*
- mode of replication
- specific host cell that virus invades
5
Q
viral genomes
A
- DNA virus (ss, ds)
- RNA virus (ss + sense or -sense, ds, retrovirus)
6
Q
steps of viral infection
A
1) attachment
2) penetration
3) uncoating
4) replication
5) assembly
6) release
7
Q
viral entry
A
- membrane fusion (enveloped virions)
- endocytosis (enveloped or naked virions)
- direct entry (naked virions)
- genetic injection (bacteriophages)
8
Q
cellular tropism
A
preferentially infect certain cell types
9
Q
tissue tropism
A
preferentially infect certain tissues
10
Q
host tropism
A
preferentially infect certain species
11
Q
cellular effects of viral infection
A
- inhibition of host cell (DNA, RNA, protein synthesis)
- disruption of lysosomal membranes
- promotion of apoptosis
- carcinogenesis
- promotion of secondary bacterial infections
12
Q
apoptosis
A
- derangement of cell metabolism triggers apoptotic pathway (many viruses suppress apoptosis)
- some viruses initiate apoptosis to facilitate infection (virions persist inside apoptotic bodies)
- apoptosis of the cell prior to virion assembly prevents spread of the infection
13
Q
outcomes of viral infection
A
- cell death
- latency
- carcinogenesis
- clearance
14
Q
viral pathogenicity depends on:
A
- host range
- cell tropism
- mechanism of replication
15
Q
common manifestations of viral infection
A
- rashes
- fever
- muscle aches
- respiratory involvement
- swollen lymph nodes
