Virus structure and taxonomy -- L1 Flashcards
Small, obligate, intracellular parasites
VIRUS
In their simplest form, viruses consist of what 2 things?
- nucleic acid
- protein
There are no _____ viruses
free living
Viruses can either be ____ or ____? but never both
DNA or RNA
Because viruses can be DNA or RNA they can be ____ or ____ stranded
single or double
usually viruses are haploid or diploid?
haploid meaning they only have one copy of the gene
What is a nucleocapsid composed of?
1) capsid – protein coat
2) viral nucleic acid
complete virus particle is called?
virion
What are some components of the structure of a virus?
nucleocapsid
± lipid envelope (host derived)
± matrix protein between nucleocapsid
envelope (‘packing material’)
What two types of proteins are seen in viruses?
1) structural
2) non-structural (enzymes)
Used to construct components of the virus
structural proteins
provides protection of viral nucleic acid
structural proteins
important in host immune response
structural protein
viral envelope derived from cell membranes?
lipids
most often as peplomers (spikes) extending outwards from the envelope
glycoproteins
used in nucleic acid and protein metabolism
non-structural (enzymes) proteins
causes shutdown of host cell function
non-structural (enzymes) proteins
What are the 2 types of capsid symmetry?
1) Icosahedral (cubic)
2) helical
virions self-assemble from where?
protein subunits
What are the 4 components of helical capsids?
1) peplomer
2) lipid envelope
3) matrix protein
4) helical nucleocapsid
a lipid bilayer formed when a virus particle buds through cellular membranes
envelope
Host derived virus envelopes have what specific component?
peplomers (spikes)
Enveloped virions are often _____ as the envelope is not rigid
pleomorphic
In formal virus taxonomy, the names of orders, families, subfamilies, genera and species are always printed in _____ and the first letters of
the names are _____.
italics;capitalized
What is an emerging infectious disease?
An existing disease that is rapidly increasing in incidence or geographic range.
What is the size range of viruses?
~17-300 nm
RBC diameter = 7000 nm
Bacteria = 1000 nm
Can viruses be seen on a light microscope?
No- its resolution is only ~300nm. Viruses are smaller than that. Need to use an electron microscope.
What are prions and viroids in relation to viruses?
Infectious agents simpler than viruses.
Viroids- infectious RNA
Prions- infectious proteins
-virales refers to the classification of _____.
Order
The word ending for the classification of family is…
-viridae
-virinae refers to the classification of ___.
Sub-family
T/F The ending of the Genus name is virus.
True. E.g. Lyssavirus
