Lecture 11: Viruses and Tree of Life Flashcards
1
Q
what is life?
A
- organized
- able to replicate itself
2
Q
virus structure
A
- protein coat (capsid)
- DNA or RNA
- no cytosol
- no plasma membrane
3
Q
capsid/protein coat
A
-contains core that contains nucleotides
4
Q
viral hereditary material
A
- DNA or RNA but never both
- circular or linear genetic material
- single or double stranded
- need a host cell in order to replicate
5
Q
virions
A
-individual virus particles
6
Q
helical shapes
A
- circular, spherical
- plant and flu viruses (influenza)
7
Q
icosahedral shapes
A
- geometric solid
- maximizes internal capacity
8
Q
binal
A
-have both icosahedral and helical shapes
9
Q
basics of viral replication
A
- virus enters cell
- cell strips off virus outer coat of protein
- nucleic acid in virus released
- nucleic acid gets into cells chemical manufacturing system
- cell switches to making new viruses
- cell sometimes destroyed in the process
10
Q
bacteriophage
A
- very small
- virus that infects bacteria
11
Q
why do some scientists argue that viruses are not alive? why do others disagree?
A
- bc they need a host to replicate, they’re not traditional cells
- others bc they are highly organized, they have the same kind of genetic storage as living things, they figured out how to replicate, they mutate, and evolve (even evolved from LIVING things)
12
Q
TSE
A
- aka transmissible spongiform encephalopathies
- virus that causes cavities in the brain
- can get it from being injected with infected tissues, transplant of infected tissues, or eating infected tissue
13
Q
TSE examples
A
-types: scrapie, bovine spongiform encephalopathies (mad cow disease), chronic wasting disease, creutafeldt-jakob disease
14
Q
prions
A
- prions don’t contain DNA (we know this b/c we hit them with radiation that would kill DNA but they’re fine)
- they’re misfolded protein
15
Q
why were prions originally called slow viruses?
A
-the time between infection and detection is very long
