ch 16 Flashcards
True or false: viruses are part of the 3 domains
False
Are viruses living organisms and why?
they do not contain cells, metabolize or respond to stimuli
Do viruses contain genetic material and reproduce?
Yes
What are the 3 points of what viruses are?
- genes wrapped in protein coat (capsid)
- have either DNA or RNA
- Some have an envelope which is an outer layer derived from the host cell’s plasms membrane
Host Range
the kind of organisms or cells that a particular virus infects
Reservoir
the site where a virus exists in nature
Bacteriophage
a virus which infects bacteria
Lytic infection
reproductive pathway in which a virus infects a bacterium, immediately replicates, then causes the host cell to burst in order to release the replicated viruses
What are the 5 types of cells viruses can infect?
- Tobacco mosaic virus (filamentous; single-stranded DNA)
- T-even bacteriophage (spaceship; double-stranded DNA)
- Rotavirus (spherical; double-stranded RNA)
- Herpesvirus (icosahedral, enveloped; double-stranded DNA)
- Poxvirus (oval, enveloped; double-stranded DNA)
What type of organisms can viruses infect?
Plant, bacteria, and human host cells
Lysogenic Infection
reproductive pathway in which the virus is replicated along with the bacterial host cell’s chromosome; the cell lives and reproduces for limited time before it bursts and releases the virus
Prophage
the DNA of a lysogenic bacteriophage that is inserted into the host chromosome
Latent Infection
virus remains dormant in host cell indefinitely
Vaccine
“weakened” viruses which are used to help host build up immunity to more potent version of the virus
5 steps of viral replication
- virus attaches to host
- virus penetrates cell and releases its DNA
- host transcribes and translates viral DNA as if it were its own
- New viruses assemble
- Viruses leave the cell
Are antibiotics effective for killing viruses?
No, since they are non-living
Examples of viral infections
common cold, polio, warts, HIV, chicken pox, flu, herpes, and ebola
2 non-cellular infectious agents other than viruses
Viroids and Prions
Viroid
Smaller than a virus, naked strand of RNA, no protein coat
Prion
Plasma membrane proteins which has an abnormal shape and can cause disease, Prions cause brain cells to die which many times leads to madness, insomnia, dementia, and eventually death.
