Virology Introduction Handout (1st Two Ppts) Flashcards
1
Q
3 reasons why viruses are beneficial
A
- biodiversity: transmit genetic material from one host to another
- residual immunity: post-infection, host can become immune to more virulent viruses
- some viruses eliminate harmful bacteria
2
Q
Properties of viruses
A
- obligate intracellular organisms
- lack organelles (i.e. mitochondria, golgi complex, ER, ribosomes)
- use host cell’s nucleus to replicate
- lack metabolic capabilities (i.e. protein synth & energy prod)
- diameter range is 20 nm to 250 nm
3
Q
Eclipse Period
A
- period where virus can’t be detected by standard testing
- is time between entry of virus into cell and production of new virus particles
4
Q
Smallest animal virus
A
Parvo
5
Q
Largest animal virus
A
Pox
6
Q
Nucleocapsid
A
- nucleic acid genome w/ protein coat
- can come in icosahedral, helical, or complex symmetry shapes
7
Q
All animal viruses contain what 2 items?
A
- DNA or RNA
- nucleocapsid (protein coat)
8
Q
Icosahedral shape
A
- pentagon w/ 20 facets
9
Q
Naked viruses
A
Lack an envelope
10
Q
Which virus only has a nucleocapsid
A
Adenovirus
11
Q
Which 2 viruses have a nucleocapsid and envelope
A
Flavivirus & paramyxovirus
12
Q
Virus
A
A general description of virus BEFORE it infects cell
13
Q
Virion
A
Mature infectious virus
14
Q
Viroid
A
Term used for plants
15
Q
Complete virion
A
- infectious and binds specifically to host cells
- ex. Poliovrus
16
Q
Virus symmetry
A
- recombinant attenuated virus gene sequence is inserted in capsid proteins -> makes recombinant virus a good candidate for blocking attachment of infectious virus
17
Q
What is the relationship between viral symmetry and infectiousness
A
They are independent of each other
18
Q
What 2 methods are used to determine viral taxonomy?
A
- PCR
- Negative staining EM
19
Q
PCR Testing
A
- amplification & sequencing of nucleic acids
- determines if DNA/RNA, family, density
20
Q
Negative staining EM
A
- Viruses are imbedded in electron dense dye & examined via EM
- Used to ID shape and size of viruses & can assign unknown viruses to a family
21
Q
9 taxonomic groups of viruses
A
- viral morphology
- nucleic acid morphology
- host they infect
- vector (if insect)
- location of viral replication (cytoplasm, nuclear, organelles)
- enveloped vs non-enveloped
- capsid symmetry
22
Q
Hierarchy of viral taxa
A
- order
- family
- subfamily
- genus
- species
