Chapter 18.1 Structure and Function Bacteria Chapter 18.1 Structure and Function

Earliest Prokaryotes (FYI) Most numerous organisms on Earth Include all bacteria Earliest fossils date 2.5 billion years old

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) Found in swamps, sewage treatment plants, digestive tracts of animals

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

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

Kingdom Eubacteria True Bacteria

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

Shapes Are Used to Classify Coccus: Spherical (round) Vibrio: Comma shaped with flagella Bacillus: Rod shaped Spirillum: Spiral shape Spirochete: wormlike spiral shape

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

Diplococcus

Streptococcus Causes Strep Throat

Staphylococcus Bacterial

Identified 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) Actinomycetes (make antibiotics) Clostridium (lockjaw bacteria) Streptococcus (strep throat) Staphylococcus (staph infections)

Gram Negative Rhizobacteria grow in root nodules of legumes (soybeans, peanuts) Fix N2 from air into usable ammonia

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

Bacteria in Nature

1. Decomposers– recycles 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

Brainpop movie http://glencoe.mcgraw-hill.com/sites/dl/free/0078759864/164155/00044676.html

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 1928. A fungus, Penicilium, contaminated a bacterial culture. Fungus produces a chemical that inhibited the bacteria penicillin.

4. Human uses b. digest petroleum in oil spills 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 oil Used to clean up oil spills

Useful Bacteria 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

5. 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