Structure of Bacteria by f0GA99A

VIEWS: 12 PAGES: 61

									   Bacteria
Structure and Function




                         1
Prokaryotes
• Most numerous
  organisms on
  Earth
  (unicellular)
• Include all
  bacteria
• Earliest fossils
  date 2.5 billion
  years old          2
Classification
   of Life
   (review)


              3
  Three Domains of
        Life
• Archaea –
 Archaebacteria -
 prokaryotes living in
 extreme habitats
• Bacteria-
  Eubacteria (including
  cyanobacteria)
• Eukarya – Protists,
  Fungi, Plants, &        4


  Animals
Bacterial
Kingdoms



            5
   Kingdom
Archaebacteria
  Ancient Bacteria



                     6
Kingdoms of Bacteria
 Archaebacteria:
  Found in harsh environments
   (extremely salty as well as
   extremely hot)
  Undersea volcanic vents,
   acidic hot springs, salty
   water
 They do not require oxygen
 Called the “Ancient
  Bacteria”
                            7
Archaebacteria




                 8
 Archaebacteria
How do they differ from
  Eubacteria?
• lack peptidoglycan in cell
  walls
• different lipids (fats) in
  their cell membrane
• different types of
  ribosomes
• Very different gene
  sequences (DNA)              9
Archaebacteria
• Subdivided into 3
  groups:

Methanogens
Thermoacidophiles
Extreme Halophiles

                      10
   Methanogens
• Live in anaerobic
  environments (no oxygen)
• Get energy by changing H2
  & CO2 to produce methane
  gas
• Found in swamps, sewage
  treatment plants, digestive
  tracts of animals
                          11
     Methanogens
• Break down
  cellulose in a
  cow’s
  stomach
• Produce
  marsh
  (methane)
  gas
                   12
Extreme Halophiles
• Live in very
  salty water
• Use salt to
  generate
  ATP (energy)
• Dead Sea,
  Great Salt
  Lake
  inhabitants
                     13
Thermoacidophiles or
   Thermophiles
 • Live in
   extremely hot
   environments
 • Found in
   volcanic vents,
   hot springs,
   cracks on ocean
   floor that leak
   acid
                       14
 Kingdom
Eubacteria
 True Bacteria



                 15
Kingdoms of Bacteria
 Eubacteria:
  Called the “True
   Bacteria
  Most bacteria are in
   this group
  Includes Producer and
   Consumer Eubacteria
                           16
Eubacteria




             17
 Producer
Eubacteria


             18
Eubacteria Producer:
   Cyanobacteria
 • Photosynthetic
 • Called blue-green bacteria
 • Contain phycocyanin (red-
   blue) pigments &
   chlorophyll
 • Important source of food
   for some organisms in
   ponds, lakes, and oceans
                          19
Cyanobacteria




                20
 Consumer
Eubacteria


             21
    Consumer Eubacteria:
  Grouped by Gram staining

• Treated with chemicals called stains
• Gram positive – stain purple because
  they have thicker cell walls (can be
  treated with antibiotics)
• Gram negative – stain pink because
  they have thinner cell walls (hard to
  treat with antibiotics)


                                      22
Bacterial
Structure


            23
 Bacterial Structure

• Microscopic prokaryotes
  (No nucleus or membrane-
  bound organelles)
• Unicellular
• Contain ribosomes
• Small rings of DNA called
  Plasmids
                          24
Bacterial Cell




                 25
    Protection

• Cell Wall made of
  Peptidoglycan
• May have a sticky
  coating called the
  Capsule for
  attachment to host or
  other bacteria      26
Sticky Bacterial
    Capsule




                   27
28
Bacterial Structure
• Most grow best at
  pH of 6.5 to 7.0
• Many act as
  decomposers -
  recycling nutrients
• Some cause disease
                        29
       Flagella
• Bacteria that
  are motile have
  appendages
  called flagella
• Attached by
  Basal Body
• A bacteria can
  have one or
  many flagella
                    30
      Flagella
• Made of Flagellin
• Used for Classification
• Monotrichous: 1 flagella
• Lophotrichous: tuft at
  one end
• Amphitrichous: tuft at
  both ends
• Peritrichous: all around
  bacteria                  31
Monotrichous    Lophotrichous




Amphitrichous   Peritrichous    32
         Pili
• Short protein appendages
• Smaller than flagella
• Adhere bacteria to
  surfaces
• Used in conjugation for
  Exchange of genetic
  information
• Aid Flotation by
  increasing buoyancy
                        33
Pili in Conjugation




                      34
Bacterial
 Shapes


            35
3 Basic Shapes Are
 Used to Classify
• Bacillus: Rod shaped
• Coccus: Spherical (round)
• Spirillum: Spiral shape




                            36
37
Bacillus - E. coli




                     38
Spirillum




            39
Grouping of Bacteria

  • Diplo- Groups of
    two
  • Strepto- chains
  • Staphylo- Grapelike
    clusters
                      40
41
Staphylococcus
   Bacterial




                 42
Diplococcus




              43
Streptococcus Causes
    Strep Throat




                       44
Review of Characteristics
     of Eubacteria…
• 3 basic shapes (coccus,
  bacillus, spirilla)
• Most are heterotrophic
  (can’t make their own food)
• May be aerobic or
  anaerobic
• Identified by Gram staining
                          45
 Nutrition,
Respiration,
    and
Reproduction

               46
Modes of Nutrition
• Saprobes – feed on dead
  organic matter
• Parasites – feed on a host
  cell
• Photoautotroph – use
  sunlight to make food
• Chemoautotroph – oxidize
  inorganic matter such as
  iron or sulfur to make food
                            47
Methods of Respiration
 • Obligate Aerobes – require
   O2 (tuberculosis bacteria)
 • Obligate Anaerobes – die if
   O2 is present (tetanus)
 • Facultative Anaerobes – don’t
   need O2, but aren’t killed by
   it (E. coli)

                             48
Bacterial Respiration
• Anaerobes
  carry on
  fermentation
• Aerobes
  carry on
  cellular
  respiration

                    49
    Reproduction
• Bacteria reproduce
  asexually by binary fission
• Single chromosome
  replicates & then cell
  divides
• Rapid
• All new cells identical
  (clones)                 50
Cellular organism copies it’s genetic information
  then splits into two identical daughter cells
                                              51
   Reproduction
• Bacteria reproduce
  sexually by Conjugation
• Form a tube between 2
  bacteria to exchange
  genetic material
• Held together by pili
• New cells NOT identical
                        52
Conjugation




              53
Useful
Bacteria



           54
   Useful Bacteria
• Medicines:
  Antibiotics &
  Vaccines to fight
  bad bacteria

• Degrade oil

• Decomposition of
  garbage and
  sewage              55
  Useful Bacteria
• Food
  Production:
  making
  yogurt,
  cheese,
  buttermilk,
  vinegar, and
  pickles.
                    56
 Useful Bacteria

Production of:
• Cleansers
• Adhesives
• Methane gas
  for fuel.

                   57
   Useful Bacteria

– Bacteria in the digestive
  systems of people and
  animals help break down
  food so that nutrients can be
  used and the waste disposed
  off. Good bacteria can fight
  of bad bacteria in the
  digestive system.
                              58
Pathenogenic
  Bacteria



               59
      Pathogens
• Called germs or microbes
• Cause disease
• May produce poisons or
  toxins




                             60
Harmful Bacteria
Cause:
• Lyme disease
• Rocky Mountain
  Spotted Fever
• Food Poisoning -
  Salmonella
• Meningitus
• Tuberculosis       61

								
To top