BACTERIA

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BACTERIA

• prokaryotes

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Bacteria Structure

• DNA Plasmids
• Cytoplasm Ribosomes
• Cell Membrane
• Peptidoglycan cell wall
• Capsule
• Pili (conjugation)

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Prokaryotic (Bacteria) vs Eukaryotic Cells

• 1) No Internal compartmentalization
• lack nucleus, ER, golgi, mito, etc
• only ribosomes

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Bacteria vs. Eukaryotic Cells

• 2) Small (cell size)
• average 1 micrometer in diameter
• eukaryotes range from 10 micro to 1 mm

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Bacteria vs. Eukaryotic Cells

• 3) Unicellular
• no cell specialization
• 4) One Chromosome
• 5) Simple Flagella
• single protein fiber
• 6) Metabolic diversity
• obligative (an)aerobe, heterotrophic,
  photosynthetic, chemoautotrophic, etc

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Bacteria vs. Eukaryotic Cells

• 7) Cell Division
• Binary fission one cell pinches into two
• no mitosis

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Bacteria vs. Eukaryotic Cells

• 8) Genetic Exchange
• a) Transformation
• DNA fragments released by broken cells
• b) Conjugation
• hollow pili grow from one bacteria to another
  then plasmids are passed
• c) Transduction
• gene transfer by bacteriophage

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Bacterial Conjugation
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Two Domains of Bacteria

• Archaebacteria
• Ancient bacteria
• Found in hot, acidic, salty extreme conditions
• Eubacteria-
• True bacteria/ common bacteria (found in common
  places)
• Peptidoglycan in their cell wall (can be Gram
  stained or -)

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Archaeabacteria

• These prokaryotes are classified separately due
  to unusual lipids in their cell membranes
• Their cell walls do not contain the compound
  peptidoglycan (protein carbohydrate compound)
  found in eubacteria.
• Heterotrophs Autotrophs - often
  chemoautotrophic
• Ancestors of eukaryotes chloroplasts

Thermoacidophile
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Thermoacidophile
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Types of Archaea

• Methanogens
• create methane,
• live in sewage and animal intestines (cows)
• Halophiles
• live in Great Salt Lake and Dead Sea, salt lovers
  
• Thermoacidophiles
• live in hot springs,
• can survive in pH of 2 and temp of 230o F

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Domain Eubacteria

• Most successful group by numbers, mass, and
  habitats

How do we distinguish them?
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1) By Cell Wall (Gram staining technique)

• Gram Positive ()
• has a thick peptidoglycan cell wall around plasma
  membrane
• Gram Negative(-)
• has thin peptidoglycan cell wall around plasma
  membrane AND an outer membrane (lipopolysaccharide
  ) layer around that

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Gram Bacteria (purple positive)

• Thick layer of peptidoglycan
• no outer membranes
• Peptidoglycan retains dye
• crystal violet stain sticks to the cell wall?
  cell stains purplish
• alcohol will not rupture the wall- it does
  nothing to peptidoglycan
• appear purplish under microscope after staining
• may be killed by penicillin strains b/c they
  prevent the formation of the peptidoglycan wall

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Gram-negative bacteria (pink negative)

• Outer membrane of lipopolysaccharide surrounding
  thin central peptidoglycan layer so crystal
  violet will not stick
• alcohol breaks down outer lipopolysaccharide
  layer
• appears pinkish/red under microscope
• susceptible to tetracycline
• resistant to penicillin
• it cant get through the outer membrane

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Classification of Eubacteria

• 2) By shape and number
• cocci-spherical
• bacilli-rod shaped
• spirilla-spiral

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Classification of Monera

• 2 cont.) By shape and number
• diplo-pairs (diplococcus)
• staphylo-clusters (staphylococcus)
• strepto-chains (streptobacillus)

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Classification of Eubacteria

• 3) By methods of obtaining energy
• a) AUTOTROPHS
• Photosynthetic
• Chemoautotrophic
• b) HETEROTROPHS

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Classification of Eubacteria

• 4) By Types of Locomotion
• sliding over slimy surfaces
• twisting through fluid
• propelling with flagella
• non-motile
• (laser disk)

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Classification of Eubacteria

• 5) By adaptation
• -endospore (very resilient!)
• -toxin (disease-causers)

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Kingdom Eubacteria (not all Gram-positive!!!)

• Phylum Gram Positive (ex Staphylococcus)
• gram positive
• Phylum Proteobacteria (Escherichia coli)
• gram negative
• Phylum Spirochetes (Treponema pallidum-causes
  syphilis)
• Spirilla, gram negative, heterotrophic
• Phylum Cyanobacteria (Anabaena)
• aerobic, photosynthetic, autotrophic, gram
  negative

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More Kingdom Eubacteria

• Examples of bacteria
• Lactobacilli causes tooth decay in your mouth
• bacteria that makes milk into yogurt
  
• Streptococci bacteria that causes strep throat
• Syphilis is caused by this sprial shaped bacteria
  that moves by rotating like a corkscrew
• Bacteria previously called Blue-green algae
• bacteria found in your intestines
• Bacteria found in the roots of plants

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Helpful bacteria

• E. coli in
• our intestines helps with digestion
• oil eaters
• sewage eaters
• makers of yogurt, cheese, sour cream, etc.
• makers of beer and wine

• decomposers recycle nutrients of dead matter
• nitrogen fixers recycle nitrogen
• copper miners help get copper from the ground
• drug makers (insulin)