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27 Cards in this Set
- Front
- Back
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Rod shaped= Bacilli
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-some bacilli have adapted to survival during unfavorable conditions by forming dormant or resting cells called endospores which are resistant to severe physical and chemical stresses
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Endospores
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-simply constructed of a central core of DNA that is surrounded by an impenetrable layer. They can remain viable for millions of years and are capable of causing some serious diseases
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Spherical shaped
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can be found as single cocci, chains or clumps
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Diploids
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pairs of spherical shaped bacteria
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Spiral shaped
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-actually are a form of rod shaped bacteria
-the size varies greatly |
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Internal=surrounded by a cell membrane
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-acts as a barrier and holds in proteins and other parts of the cytoplasm
-allows for transport of energy and materials across it via a concentration gradient |
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External=cell wall
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-composed of peptidoglycan(as opposed to cellulose in plant cells)
-2 types gram positive-have a thick cell wall gram negative-have a thin cell wall and most bacteria fall into this category -important in antibiotic use as antibiotics affect the ability to produce a cell wall |
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Flagella
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-used for motility and are driven by energy
-can be found alone, at each end, in clusters at the poles or all over the cell |
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Pill(sing. pilus)
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-used for transferring genertic material between cells
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Fimbriae
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-fine filaments of protein that aid in the attachment to other cells
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Methods of Movement
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-flagella
-bacterial gliding -twitching motility -changes in buoyancy |
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Flagella
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-rotates and driven by energy at the base
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Bacterial gliding
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-exact mechanism by which this happens is currently unknown although there are theories that include ejection of slime and movement of pili
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Twitching motility
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-special pili are used as a hook that is extended repeatedly and used to pull the bacterium along
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Changes of buoyancy
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-can reproduce internal gas vesicles that they use to regulate buoyancy in the water to find food and light
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Archaebacteria
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-live in environment without oxygen
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Eubacteria
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-live in an environment with oxygen
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Bacteria can also be grouped according to their type of respiration
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-obligate aerobes
-obligate anaerobes -facultative anaerobes |
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Obligate aerobes
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-must have oxygen to survive
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Obligate anaerobes
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-can only grow in the absence of oxygen
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Facultative anaerobes
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-prefer environments with oxygen but can live in environments without oxygen
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Nutrition
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-autotrophs
-heterotrophs -chemotrophs |
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autotrophs
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-make their own food
-photosynthesis: use of light for energy -chemosythetic: use of chemical substances for energy |
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heterotrophs
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-obtain food from other sources
-saprophytic -parasitic -symbiotic |
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saprophytic
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obtain raw materials from dead and decomposing matter
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chemotrophs
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-perform fermentation
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Modes of Bacterial disease transmission
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-direct contact
-airbone droplets -bacterial toxins in food |
