The Amazing World of Bacteria

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The Amazing World of Bacteria
Bacteria on the point of a pin!!!
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Differences Between Bacteria and Viruses

• Bacteria are classified as living
• Bacteria are prokaryotic cells
• No Nucleus
• Bacteria can perform metabolic functions
• Replication
• Protein Synthesis
• Use and obtain own energy in various ways
• Move on their own

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Classification of Bacteria

• Bacteria are classified into 2 Kingdoms
• Eubacteria Peptidoglycan in cell wall
• Affected by antibiotics
• Archaebacteria Ancient Bacteria live in
  Extreme Environments no peptidoglycan in cell
  wall
• Not affected by antibiotics

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Prokaryotes are not all bad

• Many do cause disease, but others are symbiotic
  (E. coli in intestines), help with cycling
  nutrients (decomposers and carbon cycle)
• Are about 5,000 species known, could be as many
  as 4 million

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Typical Prokaryotic Structure
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Movement How do Bacteria move around?

• Flagella help propel the cell
• On outside of cell wall
• Scattered all over surface or concentrated at the
  ends
• Slime oozes from cell
• helps bacteria glide along

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Flagella
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Cell Wall

• 2 different types of cell walls found in bacteria
• Cell walls containing peptidoglycan on outside
  layer
• Cell walls containing outer lipid carbohydrate
  layer over peptidoglycan layer
• Antibiotics target only those bacteria mainly
  with peptidoglycan in cell wall
• Use Gram Stain
• Gram () means peptidoglycan in outer wall -
  purple
• Gram (-) means outer layer of lipid/carb covers
  peptidoglycan layer- pink/red
• Antibiotics only kill Gram () bacteria

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Mix of Gram() and (-) Bacteria
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Structure of Bacteria Groups, shape, and size
range

• Most are unicellular, but some may aggregate in
  groups of two or more
• Others are true colonies permanent groups of
  identical cells chains (strepto)
• clusters (staphalo)
• Differ in shape 3 most common
• spherical (coccus or cocci)
• rod-like (bacillus or bacilli)
• helical (spirillum or spirilla, spirochetes)
• Diameter ranges between 1-5 um largest is .75 mm
  in diameter

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Draw these shapes in your notes and know their
names!!!
Cocci
Bacillus
Spirillum
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Bacterial Modes of Nutrition Very Diverse

• Nutrition of prokaryotes how org obtains energy
  and a carbon source to build org molecules
• Are 4 categories
• 1. photoautotrophs use light to make food
• 2. chemoautotrophs need CO2 as carbon source,
  and get chemical energy from inorganic substances
• 3. photoheterotrophs use light to make
  energy, but need a carbon source to start with
• 4. chemoheterotrophs must eat other
  organisms to get food in chemical form (most
  bacteria are this type saprobes and parasites)

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Bacterial ReproductionBinary Fission

• Asexual Reproduction - No recombination of
  genetic material!
• Bacterial cell just splits in half and have two
  cells from the original

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Endospore Bacterial Protection Phase

• If growth conditions are not suitable for
  bacteria
• It grows a thick internal wall
• protects bacteria
• Can remain dormant indefinitely
• Can grow once conditions return to favorable

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Figure 27.10x Endospores
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Ecological Impact of Prokaryotes

• Recycling of 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
  -- pseudomonads
• Act as metabolic factories for human use
• -produce acetone, butanol
• -make vitamins, antibiotics
• -food flavorings (yogurt, cheese)
• -DNA technology produce hormones like insulin

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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

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Path of Transmission

• recreates the pattern by which a disease spreads
  among a population.
• (are looking for the original case the first
  organism who had the disease or that carried it
  but was unaffected!)
• Other names for the original case Index Case
• Patient Zero
• Typhoid Mary

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• At a party, Joe, Shawn, Martha, Alice, Rob,
  Peter, and Cathy have unprotected sex at some
  point during the evening. Two years later, all
  of them discover that they are HIV EXCEPT for
  Shawn, Peter, and CathyGiven the following
  sharing pattern, who was Patient Zero?
• Party goers First partner Second
  partnerJoe Martha AliceShawn Joe MarthaRo
  b Martha JoeCathy Shawn PeterMartha Joe
  RobAlice Shawn RobPeter Shawn Cathy