Prokaryotes

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Prokaryotes

• Kingdoms Eubacteria Archaebacteria

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Prokaryote Before nucleus

• Characteristics
• Unicellular
• 1-5 µm diameter
• Cell walls
• -Maintains shape
• -Provides protection
• -Prevents lysis in a hypotonic environment

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Prokaryotes
Eukaryotes
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Prokaryotes
Eukaryotes
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Bacteria

• Single-celled prokaryotes
• Two kingdoms of bacteria
• Archaebacteria
• Eubacteria

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Archaebacteria

• Methanogens Anaerobic bacteria (oxygen is a
  poison) Produce energy by converting H2 CO2
  into methane gas. Live in swamps marshes
• Extreme Halophiles Salt-loving" bacteria that
  use salt to generate ATP for energy.
• Thermoacidophiles Live in extremely acidic
  environments (pH less than 2) that have extremely
  high temperatures (up to 110o C). e.g.
  geothermal springs at Yellowstone National Park.

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Archaebacteria
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Eubacteria

• Contains the bacteria commonly referred to as
  germs.
• This kingdom contains most of the world's
  bacteria
• Eubacteria are classified by
• Shape
• Clustering
• Respiration

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Eubacteria Shape

• Coccus - round
• Bacillus - rod-shaped
• Spirillum - spiral-shaped

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Eubacteria Clustering

• Diplo - a prefix used with the shape name to
  indicate pairing of cells.
• Strepto - a prefix used with the shape name to
  indicate chains.
• Staphylo - a prefix used with the shape name to
  indicate clusters

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Streptococcal (Group A) Infections
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Susceptibility Resistance
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Eubacteria Respiration

• Obligate anaerobes - cannot survive in the
  presence of atmospheric oxygen.
• Facultative anaerobes - can live with or without
  atmospheric oxygen.
• Obligate aerobes - cannot survive without
  atmospheric oxygen.

MRSA Staphylococcus aureus
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The acronym MRSA stands for methicillin-resistant
Staphylococcus aureus
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Maggots Rid Patients Of Antibiotic-resistant
Infection, MRSA
ScienceDaily (May 5, 2007) University of
Manchester researchers are ridding diabetic
patients of the superbug MRSA - by treating their
foot ulcers with maggots.
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Gangrene
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Tetanus
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Necrotizing Fasciitis
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Leprosy
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Helicobacter pylori
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Lyme Disease
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Gram Staining
Many antibiotics have no effect on gram-negative
bacteria
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• Gram-positive. Gram-positive bacteria have a cell
  wall with a large amount of peptidoglycan that
  traps the violet dye in the cytoplasm. The
  alcohol rinse does not remove the violet dye,
  which masks the added red dye.
• Gram-negative. Gram-negative bacteria have less
  peptidoglycan, and it is located in a layer
  between the plasma membrane and an outer
  membrane. The violet dye is easily rinsed from
  the cytoplasm, and the cell appears pink or red
  after the red dye is added.

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• Using a technique called the Gram stain
• Scientists can classify many bacterial species
  into two groups based on cell wall composition,
  Gram-positive and Gram-negative

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Bad bacteria - toxic
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Toxins

• Substances that disrupts the metabolism of other
  organisms.
• Endotoxin - made up of lipids and carbohydrates
  associated with the outer membrane of
  gram-negative bacteria. These toxins are some of
  the strongest poisons known to man and cause
  violent reactions in host organisms.
• Exotoxin - proteins produced inside gram-positive
  bacteria cells and secreted into the environment.
  These toxins usually produce fever, weakness, and
  capillary damage.

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Parts of a bacteria cell

• Cell wall - some rigid and others flexible.
• Cell membrane - same as other cells.
• Cytoplasm - same as other cells.
• DNA - a single, circular chromosome (Plasmid)
  located in the cytoplasm. Bacteria do not have a
  nucleus.
• Capsule - a thick, gel-like, protective coating
  on some bacteria cells.
• Pili - short, hairlike protein structures on the
  surface of some bacteria that help them stick to
  host cells.
• Flagella - long protein structures that turn to
  propel some bacteria cells.

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• The cell wall of many prokaryotes
• Is covered by a capsule, a sticky layer of
  polysaccharide or protein

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• Fimbriae and pili
• allow bacteria to stick to their substrate or
  other individuals in a colony

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Taxis movement toward or away from a stimulus
chemotaxis movement toward chemical -
chemotaxis movement away from chemical
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Reproduction

• Asexual, by binary fission - the DNA replicates
  and then the cell pinches inward and splits in
  two.
• Conjugation - two cells exchange a portion of
  their DNA across a bridge formed between the
  cells. New material replaces old material in the
  cell. While this increases the genetic
  variability in the organisms, it is not true
  sexual reproduction.
• Endospores - during adverse conditions, the DNA
  is encased in a protective envelope. This
  endospore can lie dormant for years or until
  favorable conditions return.

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Binary Fission
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Conjugation
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Endospores
Can remain viable in harsh conditions for
centuries
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Prokaryotic Metabolism
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Antibiotics

• Drugs that fight bacteria by interfering with
  their cellular functions.
• PENICILLIN interferes with cell wall synthesis.
• TETRACYCLINE interferes with protein synthesis.
• Many antibiotics are derived from chemicals that
  bacteria or fungi produce.
• SULFA DRUGS - antibiotics that are synthesized in
  laboratories
• Many Antibiotics are able to affect a wide
  variety of organisms they are called BROAD
  SPECTRUM ANTIBIOTICS.

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Antibiotic Resistance

• When a population of bacteria is exposed to an
  Antibiotic, the most susceptible DIE. 
• A Few Mutant bacteria that are resistant to the
  Antibiotic may continue to grow.
• A Resistant Population then grows from these
  Mutant Bacteria through reproduction and genetic
  recombination.
• These new Population are Antibiotic-Resistant. 
  This has resulted from the Over Use of
  Antibiotics.  Many diseases that were once easy
  to treat are becoming more difficult to treat.

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USEFUL BACTERIA

• Used in Sewage Treatment, and as Decomposers,
  breaking down the remains of organic matter in
  dead plant and animal waste.  Recyclers,
  returning nutrients back to the environment.
• Food production.  Bacteria help us make
  buttermilk, sour cream, yogurt, cottage cheese,
  sauerkraut and pickles.
• Used in industrial chemical production.  They
  produce organic chemicals and fuels. Theyre used
  in the mining of minerals and their products are
  used as insecticides.
• Used to help clean up environmental disasters
  caused by humans, such as chemical and oil
  spills.

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• Prokaryotes are the principal agents in
  bioremediation
• The use of organisms to remove pollutants from
  the environment

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