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when were viruses discovered ?
seen in 1935
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what is the basic structure of a virus?
nucleic acid , capsid , tail sheath , bacteriaphage
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why are viruses not living ?
- -cannot reproduce without a host cell
- -not made of cells
- -do not require energy
- -do not grow and develope
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why do some think that they are alive ?
they can evolve
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what are the possible shapes of viruses
- polyhedrial
- helical
- spherical
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viruses capsids allow them to -
attach only to specific cells
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What are some common viruses?
- -common cold
- -flu
- -polio
- -rabies
- -hpv
- -papiloma virus
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What is the lytic cycle?
-get in , take over, destroy the cell
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What are the steps in the lytic cycle ?
- 1. attachment ( attaches to the cell)
- 2. injection(DNA is incerted into the cell )
- 3. Take over(enzymes chop up the host)
- 4.Manufacture (cell produces viral capsid & DNA)
- 5. Assembly
- 6. Release (an enzyme opens cell membrane then virus comes out)
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What is the lysogenic cycle ?
you get it you have it forever
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What are the steps in the lysogenic cycle?
- 1. Attachment
- 2. injects
- 3.provirus fromation (viral DNA attaches to the host cell DNA * cell carries on normal functions
- 4.Host cell Reproduction ( copies virus DNA into all new daughter cells)
- 5. Activation(a trigger causes the virus DNA to activate)
- 6. Take over
- 7. Manufacture
- 8. Assembly
- 9. Release
ex : HIV, Herpes, Hepititus, Chicken Pox
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What are retroviruses ?
- RNA viruses
- * RNA-> DNA
- reverse transcriptase enzyme
ex: HIV
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How can you prevent viral infections ?
- Vaccination
- * produce memory cells
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Interferon -
produced by infected cells - signals uninfected cells to set up a protective barrier
* white blood cells
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What are the two kingdoms of bacteria?
- - archeabacteria
- - eubacteria
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What are the general characteristics of bacteria
prokaryotic / unicellular / cell walls
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Eubacteria -
- Cell wall
- peptidoglycan (protein / sugar)
- Modern Bacteria - infect us
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what is the structure of DNA ?
Flagella, cilia, cell membrane, pilus ( reproduction) cell wall, Capsule, Ribosomes, DNA (circular) plasmids (small pieces of DNA)
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What are some bacterial shapes?
- coccus (spherical)
- Bacillus ( rod shaped)
- Spyrilla ( spiral )
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Example of coccus bacteria
strepococcus, staphlococcus
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example of Bacillus
e-coli
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example of spyrilla
sphyilis
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what are the life processes?
movement , gas exchange, nutrition, reproduction
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what does obligate mean ?
must be ...
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what does faculative mean ?
perfer
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how do bacteria move?
contact transfer - cilia-flagella-gliding
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Types of Gas exchange...
- aerobic- requires oxygen
- anaerobic- doesnot require oxygen
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Bacterias nutrition
- photosynthetic autotroph - uses light and co2 for energy
- chemosynthetic autotrophs - nuses chemical and co2 for energy
- ex thermal vent bacteria
heterotrophic- eat things for energy
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types of reproduction :
- asexually - binary fission
- sexual - transfer of plasmids
- *conjugation
- *utalizes a pilus to transfer plasmids
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What are endospores?
- a protective "structure" cantaining DNA and a protein coat
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when are endospores produced?
when the bacteria is in harsh conditions- too hot or cold- too dry- no food
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whats is an autoclave ?
a pressure cooker to destroy bacteria - medical use
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What are the benefits of bacteria?
help digest food and produce vitamins-intestines- Decomposers- saprophites- Nitrogen Fixation , Food flavoring , antibiotics,transgenic bacteria
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Nitrogen Fixation
-soil bacteria that convert n2 to no3
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what are the characteristics of archae bacteria ?`
thrive in very harsh conditions- have cell walls made of psedomurine
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what is psedomurine
carbohydrate / protein
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methanogens
bacteia that lives in digestive systems of large mammals
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what are some harmful effects of bacteria?
- eat you
- toxins
- exotoxins
- endotoxins
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howdo you control bacteria?
wash well need food moisture appeophate tempretures
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