Viruses Flashcards
1
Q
viruses are
A
non cellular organisms with genetic element (nucleoprotein: RNA/DNA) that cannot replicate independently if there is no living (host) cell
2
Q
Structure of Viruses:
A
- Icosahedral: 20 faces, each an equilateral triangle
- Helical: protein binds around DNA/RNA in a helical fashion
- Complex: neither icosahedral or helical
3
Q
Viruses are obligate intracellular pathogens.
This means that
A
they can only replicate inside host cells
4
Q
most viruses have tissue tropism.
This is when
A
viruses have a specific host range and so infect a specific host cell type or tissue as they support the growth of the virus.
5
Q
Virus families can be classified according to:
A
- Virion shape / symmetry
- Presence / absence of envelope
- Genome structure
- Mode of replication
6
Q
Taxonomy of Viruses
A
- Order
- Family
- Genus
- Species
7
Q
A virion contains:
A
- spike projections
- lipid envelope
- protein caspid
- virion associated polymerase
- nucleic acid
(outer to inner)
8
Q
virus replication occurs as a cycle:
A
- attachment (to cell)
- uncoating
- replication of genomic nucleic acid
- protein synthesis
- virion assembly
- budding and release
- maturation
- attachment to new cell
9
Q
Host Range in virus
A
- Some viruses may only infect humans, e.g. smallpox, measles,
- Some may also infect other animals / birds
- Transmission of a novel virus to humans
- Co-infection of human and animal or bird strains in one
organism may lead to recombination and generation of
a new strain
