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					BACTERIA
 p. 470-481
Prokaryotes
   ALL cells have:                                            Ribosome
       Cell membrane       Peptidoglycan
                                             Cell     Cell
                                             wall   membrane
       Cytoplasm
       DNA
       Ribosomes
   ALL prokaryotes have:
       Cell wall
   Prokaryotes MAY have:
       Flagellum – movement
       Capsule – protection,
        attachment
       Pili – attachment               Flagellum       DNA    Pili

       Sex pili – conjugation
        (exchange of DNA)
Cell Parts
            1




                2


8
7

    6

        5



    4

                    3
                              Bacteria

                are classified into the kingdoms of



                                                 Archae-
       Eubacteria
                                                 bacteria
   include a variety of                         live in harsh
    lifestyles such as                     environments such as


Living in       Infecting       Thick       Animal          Salty     Hot
   soil           large         mud        digestive        lakes   springs
               organisms                     tracts
Taxonomy

    Kingdom Eubacteria
        Cell wall with peptidoglycan (a carb)
        Gram stain + (purple)



    Kingdom Archaebacteria
        Cell wall with no peptidoglycan
        Gram stain – (red)
        Interestingly, the DNA is more similar to eukaryotes
         than other bacteria
Peptidoglycan
Shapes




   Corkscrews   Rods   Spheres
What are Bacteria Good For?
    Food!
        Cheese, yogurt, buttermilk, sour cream
        Pickles, sauerkraut, vinegar
    Digestion
        Many beneficial bacteria in your large intestine
    Purification
        Drinking water
        Sewage treatment
        Cleaning up oil spills
    Genetic engineering
        Transgenic organisms
        Producing drugs or other chemicals
Roles in the Ecosystem
   Decomposers
       Break down & recycle nutrients
   Nitrogen fixers
       Make atmospheric N available for plants
       Mutualism with certain plants (ex:
        legumes)
   Pathogens
       Some bacteria directly attack living
        cells/tissues
       Some bacteria produce toxins that
        make a person sick
Bacterial Growth
    Binary Fission
        Asexual reproduction (cell ÷ into 2)
        Some can ÷ every 20 min
        Some form chains, others clusters, others are
         random
    Conjugation – transfer of genetic material
     through sex pili
        Why? Increases genetic variation
    Some bacteria can form an endospore to go
     dormant until conditions become more
     favorable
Preventing Bacterial Growth

  Heat kills (boiling, canning food)
  Disinfectants kill (ex: bleach)
  Refrigeration – only slows growth
  Salt, vinegar, & sugar were used to preserve
   food before refrigeration

				
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posted:2/5/2013
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