Bacteria

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Bacteria
Once all bacteria were in kingdom Monera Now all
bacteria are split into 2 kingdoms -Kingdom
Archaebacteria -Kingdom Eubacteria
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Two Kingdoms of Bacteria

• Kingdom Archaebacteria
• Cell walls lack peptidoglycan, a carbohydrate
  found in the cell walls of eubacteria
• More like Eukaryotes than Eubacteria
• Live in harsh environments

• Kingdom Eubacteria
• Cell walls contain peptidoglycan
• Some eubacteria have a second, outer, membrane.
• Most Bacteria are Eubacteria

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Bacteria

• All bacteria are prokaryotes
• have no nucleus
• All bacteria are unicellular
• single celled
• All have cell walls

This is two cells colonizing not a two celled
organism
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Classifying Bacteria

• Prokaryotes are identified by their
• Shapes
• Size
• Groupings
• The ways they move
• Cell walls
• Colonization features
• Nutrition

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Bacteria Shapes
rod-like (bacillus or bacilli)
spherical (coccus or cocci)
helical (spirillum or spirilla)
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Bacteria Size

• Bacteria are small
• Diameter ranges between 1-5 um largest is .75 mm
  in diameter

Bacteria on the point of a pin
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Bacteria Groupings

• All bacteria are unicellular but some colonize
• Groupings can be in
• chains (strepto)
• clusters (staphalo)

Streptococcus
Staphylococcus
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The Ways They Move

• Movement
• Brownian movement- random movement
• Spirochetes have cork-screw movement
• Some secrete slimy threads and glide along

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Cell Wall of Eubacteria

• Eubacteria cell walls contain peptidoglycan, a
  carbohydrate.
• Some Eubacteria have a second, outer, membrane.
  This can be determined by Gram Staining

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Gram Staining

• Adds dye to bacteria way stains is indication
  of bacterial cell wall type
• Gram positive stains PURPLE has simple, thick
  cell wall
• Gram negative stains PINK has a protective
  outer cell membrane.
• Gram negatives are more resistant to
  antibiotics

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Figure 27.5x Gram-positive and gram-negative
bacteria
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Colonization Features

• Colonies will have certain features when a
  culture is grown on a petrie dish
• May be smooth, rough, various colors, etc.

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The Structure of a Eubacterium
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Bacteria Structures

• Flagella- whiplike structure on some cells that
  is used for movement
• Pili- surface appendages that hold on to
  substrates
• Endospore- type of spore formed when a bacterium
  produces a thick internal wall that encloses its
  DNA and a portion of its cytoplasm

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Bacterial Reproduction

• Binary Fission- type of asexual reproduction in
  which a prokaryote replicates its DNA, and
  divides in half, producing two identical daughter
  cells

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Bacterial Reproduction

• Conjugation- A form of sexual reproduction in
  some prokaryotes exchange genetic information

Pili for conjugation (sexual transfer of genetic
material)
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Nutritional Diversity

• Nutrition of prokaryote how org obtains energy
  and a carbon source to build organic molecules
• Categories
• Autotrophs
• a. photoautotrophs
• b. chemoautotrophs
• Heterotrophs
• c. photoheterotrophs
• d. chemoheterotrophs

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Photoautotrophs

• Photosynthetic
• Harness light energy to make organic compounds
  from CO2
• Ex. cyanobacteria

Energy From the sun
Photo autotroph
Make own organic molecules (ex. Sugars from CO2)
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Chemoautotrophs

• Need only CO2 as carbon source
• Break down inorganic substances (nonliving
  things) to get energy

Energy From the inorganic materials
Chemo autotroph
Make own organic molecules (ex. Sugars from CO2)
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Photoheterotrophs

• Use light to generate ATP but must get carbon in
  organic form

Energy From the sun
Photo heterotroph
Must eat or absorb organic molecules
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Chemoheterotrophs

• Must consume organic molecules for energy and
  carbon
• Very common in prokaryotes
• saprobes decomposers that absorb nutrients
  from dead organic matter
• parasites absorb nutrients from body fluids of
  living hosts

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Bacteria in Nature

• Nitrogen fixation- converting nitrogen gas in the
  atmosphere into a form that plants can use
• Can be done by only certain nitrogen fixing
  bacteria
• Many plants have symbiotic relationships with
  nitrogen fixing bacteria
• Rhizobium is a nitrogen fixing bacteria that
  symbiotic with the roots of soybean plant

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Ecological Impact of Prokaryotes

• recycle nutrients (decomposers)
• Symbiotic relationships interact with other
  orgs and form food webs
• Cause many diseases
• opportunisitic (normal residents, but cause
  disease when immune system is weak)
• Bioremediation use or orgs to remove pollutants
  from water, air, and soil
• Ex. Sewage treatment plants anaerobic prok
• Ex. Decompose petroleum compounds at oil spills
• Act as metabolic factories for human use
• -produce acetone, butanol
• -make vitamins, antibiotics
• -food flavorings (yogurt, cheese)
• -DNA technology produce hormones like insulin
• Flavors many foods cottage cheese, yogurt, sour
  cream, coffee, chocolate, butter, soy sauce

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Preventing Bacterial Infection

• Sterilization of surfaces (with antiseptics,
  heat, or steam)
• Cooling, freezing food
• Dehydrating food (salt curing)
• Use chemical preservatives (food or water
  chlorine)
• Radiation
• Pasteurization (heating liquids)
• Canning
• Washing hands
• Antibiotics are used only AFTER have infection
  present

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Antibodies vs. Antibiotics vs. Antiseptics

• Antibodies produced by white blood cells in the
  body (internal line of defense)
• Antibiotics kill bacteria using chemicals that
  are produced OUTSIDE of the body by other sources
  then
• introduced IN TO body as injection or ON TO
  site of infection as surface medication

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• Antiseptics Kill bacteria on OUTSIDE of body or
  on membranes that line areas leading to inside
  (ex. Mouth)
• Ex. Alcohol
• Listerine
• Iodine
• Hydrogen Peroxide
• Disinfectants act as surface antiseptics for
  non-living surfaces before bacteria even get to
  body
• Ex. Chlorox
• Lysol
• Ammonia