Microbiol exam 2
Terms
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- porcelain filters used to filter( remove) bacteria
- charles chamberland
- some filtrates remained infectious???
- dmitri ivanovsky
-
"contagium vivium fluidium" contagious living fluid
Later coined the name virus(meaning poison or venom) - martinus beijerinck
- prior to 1930's : lack of technology needed to :
-
isolate
propagate
observe and analyze was not available -
crystallizied the first virus(TMV), consisted of protein and RNA
viruses first obsered with an electron microscope - wendell stanley
- certain inherited traits seem to be passed from parent to offspring as discrete hereditary : particles"
- mendel's particles: gregor mendel
- genetic material of some virus was DNA
- hershey and chase
-
contain a single type of nuclei acid , either DNA or RNA
contain a protein coat(capsid) around the nucleic acid
is antigenic/immunogenic (stimulates antibody production)
some virus have an envelop around the protein coat
mutiply insid - general characteristic and structure of viruses
- shapes:
-
helical/ spiral
icosahedral (20 sided polyhedron)
enveloped
complex - phage tail fibers attach to specific receptors on bacteria
- attachment/ adsorption
-
phage release enzyme->
Lysozyme: dissolves part of the bacteria cell wall
tail sheath contracts and drives phage core through the cell wall - penetration
- viral DNA takes over the machinery of the host cell and begin producing viral DNA and structural components
- biosynthesis
- phage DNA assembles into complete viruses
- maturation/ assembly
- phage lysozyme breakd down bacteria cell wall and mutiplied phages are released
- release/ lysis
- the time from adsorption to release
- burst time