Domain Bacteria and Domain Archaea Bacteria: Archaea BASIC CHARACTERISTIC of Both: Unicellular Heterotrophic or Autotrophic Prokaryotic

Eubacteria “True Bacteria” Archaea “Ancient” - extremophiles - Thermophiles, - Methanogens (salt) (anaerobic waste removal) (Hydrothermal vents) - Halophiles

How do Bacteria and Archaea differ?  Domain Bacteria  Structural:  Peptidoglycan in cell wall  Molecular:  Simple RNA polymerases Domain Archaea Structural: No peptidoglycan in cell wall. Molecular: Complex RNA polymerase

 Gram staining is used to identify bacteria. Gram-negative bacteria have a thin layer of peptidoglycan and stain red/pink. Gram-positive bacteria have a thicker peptidoglycan layer and stain purple. –Stains the peptidoglycan layer. –Gram-positive = Stain color - purple, Thick peptidoglycan cell wall –Gram-negative = Stain color - Pink, Thin peptidoglycan cell wall + outer membrane. E. coli B.subtilis

Why are some bacteria resistant to certain antibiotics? GRAM NEGATIVEGRAM POSITIVE

How bacterial resistance occurs!

 Basic Bacterial Structure flagellum pili cell wall Nucleic Acid cell membrane Ribosome Plasmid

Bacteria are Classified by Shape and Growth Pattern – Spirilla = spiral shaped – Bacillus = rod shaped – Coccus = spherical shaped - Diplo = pair - Strepto = chain - Staphylo = cluster

Test yourself…Classify these bacteria? Streptobacillus Diplococcus Streptococcus Spirillus

Genetic Variation in Bacteria Transformation – Bacterial picks up free DNA and adds it in to its own DNA. Conjugation –One bacteria transfers DNA to another. Mutation – Random change in a DNA sequence.

How are Bacteria helpful?  Benefit to Ecosystems  Decomposition (CO2)  Chemical Cycling  Fix nitrogen in the soil (air to soil)  Cyanobacteria (photosynthesis)  Bioremediation – The use of organisms to remove or neutralize pollutants from a contaminated site  Provide Nutrients:  Digestion of food in gut  Cheese, butter, yogurt, sauerkraut

How are bacteria harmful?  Pathogens: Cause Disease  Scarlet Fever - Streptococcus pyogenesStreptococcus pyogenes  Strep Throat – Streptococcus pyogenes  Bacterial Meningitis - Neisseria meningitidisNeisseria meningitidis  Lyme Disease - Borrelia burgdorferiBorrelia burgdorferi  Produce toxins  Botulism  Clostridium botulinum  The chemical used in botox  Food Spoilage  Antibiotic Resistance

What do we use to fight infection?  Antibiotics  Vaccines  Antiseptic

Antibiotics Vs Vaccines  Antibiotics only treat bacterial infections  Given after someone is infected  Prevents bacterial growth  Vaccines treat viral or bacterial diseases  Given prior to infection  Is made up of a small dose of the pathogen  Creates antibodies to fight future infections

Antibiotic Sensitivity  Antibiotic Sensitivity - the susceptibility of bacteria to antibiotic  To test antibiotic sensitivity -  Thin wafers containing an antibiotic are placed on an agar plate that is growing bacteria. The bacteria are can’t grow next to the antibiotic they are sensitive to.

 Zone of inhibition - area around antibiotic disc where bacterial growth is inhibited.  Antibiotic Resistance - No clear zone (indicate antibiotic resistance)  Antibiotic discs are identified by the letter on the top. AntibioticIdentifier Penicillin P ChloramphenicolC DoxycyclineD StreptomycinS CiprofloxacinCIP ControlCNTL

Zone of inhibition P D C CIP S CNTL 2cm 4 cm 5 cm 4 cm 1 cm

CIP S P CNTL D C 1 cm 2 cm 3 cm 4 cm 0 cm