Bacteria Chapter 18.1 Structure and Function

1. Prokaryotes  microorganisms, lack nucleus, single cell a. Monera  old kingdom b. divided into 2 domains: archaea and bacteria c. kingdoms  Eubacteria and Archaebacteria

2. Cell wall different in two domains Eubacteria cell walls have peptidoglycan Archebacteria  cell walls lack peptidoglycan, extreme environments, many anaerobic

Methanogens Live in anaerobic environments (no oxygen)Live in anaerobic environments (no oxygen) Found in swamps, sewage treatment plants, digestive tracts of animalsFound in swamps, sewage treatment plants, digestive tracts of animals

Extreme Halophiles Live in very salty waterLive in very salty water Use salt to generate ATP (energy)Use salt to generate ATP (energy) Dead Sea, Great Salt Lake inhabitantsDead Sea, Great Salt Lake inhabitants

Thermoacidophiles or Thermophiles Live in extremely hot environmentsLive in extremely hot environments Found in volcanic vents, hot springs, cracks on ocean floor that leak acidFound in volcanic vents, hot springs, cracks on ocean floor that leak acid

Kingdom Eubacteria True Bacteria

Characteristics 3 basic shapes (coccus, bacillus, spirilla)3 basic shapes (coccus, bacillus, spirilla) Most are heterotrophic (can’t make their own food)Most are heterotrophic (can’t make their own food) May be aerobic or anaerobicMay be aerobic or anaerobic Identified by Gram stainingIdentified by Gram staining

Shapes Are Used to Classify Coccus: Spherical (round)Coccus: Spherical (round) –Ex: Strep & Staph Bacillus: Rod shapedBacillus: Rod shaped –Ex: E. coli Spirillum: Spiral shapeSpirillum: Spiral shape –Ex: Spirochete: wormlike spiral shape Treponema pallidum (Syphilis)Treponema pallidum (Syphilis) Borelia burgdorferi (Lyme Diseae)Borelia burgdorferi (Lyme Diseae)

Identified by Arrangement Strepto  long chains Staphlo  grapelike clusters Diplo  pairs

Diplococcus Grape Cluster

Diplococcus

Streptococcus Causes Strep Throat

Staphylococcus Bacterial

Bacteria Can Be Identified by Gram Stains Gram stains  dyes used to stain cells –If pink  gram negative Thin layer of peptidoglycan Hard to treat with antibiotics –If violet  gram positive Thick layer of peptidoglycan Can be treated with antibiotics

Gram Positive Bacteria (FYI) Lactobacilli (makes yogurt & buttermilk) Lactobacilli (makes yogurt & buttermilk) Actinomycetes (make antibiotics) Actinomycetes (make antibiotics) Clostridium (lockjaw bacteria) Clostridium (lockjaw bacteria) Streptococcus (strep throat) Streptococcus (strep throat) Staphylococcus (staph infections) Staphylococcus (staph infections)

Gram Negative Rhizobacteria grow in root nodules of legumes (soybeans, peanuts)Rhizobacteria grow in root nodules of legumes (soybeans, peanuts) Fix N 2 from air into usable ammoniaFix N 2 from air into usable ammonia

Gram Negative Rickettsiae are parasitic bacteria carried by ticksRickettsiae are parasitic bacteria carried by ticks Cause Lyme disease & Rocky Mountain Spotted FeverCause Lyme disease & Rocky Mountain Spotted Fever

Bacteria in Action

1. Decomposers– recycle nutrients a. sewage treatment  breakdown complex substances

2. Nitrogen fixation a. bacteria grow on knobs, nodules, on roots of certain plants. Convert nitrogen gas into ammonia, a nitrogen form usable by plants b. Nitrogen needed for amino acids, amine group  NH2

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3. Diseases a. damage tissue: tuberculosis (lungs), strept throat, Pneumonia, typhoid, cholera, tooth decay b. release toxins c. treatment: vaccines and antibiotics –Antibiotics accidentally discovered by Fleming in A fungus, Penicilium, contaminated a bacterial culture. Fungus produces a chemical that inhibited the bacteria  penicillin.

4. Commercial Uses a. cheese, yogurt, buttermilk, sour cream, pickles, vinegar b. digest petroleum in oil spills c. synthesize drugs in bioengineering

Useful Bacteria Some bacteria can degrade oilSome bacteria can degrade oil Used to clean up oil spillsUsed to clean up oil spills

Useful Bacteria Other uses for bacteria include making yogurt, cheese, and buttermilk.Other uses for bacteria include making yogurt, cheese, and buttermilk.

Making cheese, 3.5 minutes video\cheese, Milking_the_Cow.wmv

Making cheese, 4 minutes video\cheese, churning.wmv

Controlling bacteria a. Sterilization  great heat or chemicals used to destroy bacteria b. Disinfectants  a chemical solution kills bacteria; used in hospitals, homes (bathrooms and kitchens) c. Refrigeration  bacteria are slowed down d. Canning (heat)  salt, vinegar, or sugar