Today Pick up a handout Schedule Wrap up immunity Bacteria notes Start microscope lab

Bacteria - Kingdom Monera

Objectives Eubacteria vs. Archaebacteria Typical bacteria structure Bacterial classification How bacteria obtain genetic variation Uses and harmful effects of bacteria

History of Life

III. Kingdom Archaea “bacteria” Have no peptidoglycan in their cell wall more closely related to eukaryotes (ribosomes) Different lipid composition in plasma membranes Live in harsh climates Methanogens – oxygen-free environment like intestines, swamps, sewers (produce methane gas) Thermophiles – hot environments – undersea volcanic vents, hot springs Halophiles – salty environments – Great Salt Lake, Dead Sea Acidophiles – live in extreme pH

Bacterial Respiration Obligate aerobes – organisms that require a constant supply of oxygen in order to live. EX: Mycobacterium tuberculosis, the bacterium that causes tuberculosis. Obligate anaerobes – do not require oxygen; some may be killed by O2! EX: Clostridium botulinum, found in soil and can grown in canned food causing fatal food poisoning. Facultative anaerobes – can survive with or without O2. EX: E. coli, can live in the large intestines contaminated water.

Respiration Obligate Anaerobe Microaerophile Obligate Aerobe Facultative Anaerobe Aerotolerant

Eubacteria Prokaryotic (no nucleus) – larger than viruses Peptidoglycan in cell wall Can be decomposers

Other structures Capsule – outer layer made of polysaccharide or protein, used for adhesion Fimbriae – specialized pili for attachment Plasmid – extra circular pieces of DNA

Classified by Nutrition Movement Shape How they colonize (clusters, pairs, etc) Cell wall composition Production of endospores

Nutrition Photoautotrophic – photosynthetic, use sunlight for energy, CO2 for carbon (cyanobacteria, algae, plants) Chemoautotrophic – use inorganic compounds as electron donor for energy, uses CO2 for carbon (some prokaryotes) Photoheterotrophic – sunlight generates ATP, must get carbon from organic molecules (some prokaryotes) Chemoheterotroph – energy and carbon must come from organic compounds (most organisms including prokaryotes)

Bacillus - rods Coccus - round Sprillium - spirals

(Chains) (Clusters)

Gram Stain

Classified by Gram Stain Gram Positive 1 cell wall of glycoproteins & lipid Stains PURPLE because stain penetrates the single wall Gram Negative Has 2nd outer layer – prevents stain from penetrating (Purple stain washes off) New RED stain applied and sticks Resistant to antibiotics

Endospore – protects the cell against harsh environmental conditions, such as heat and drought. May allow the bacterium to survive for thousands of years.

Today Have out: Bacteria notes Lab Diagram Sheet

Objectives Eubacteria vs. Archaebacteria Typical bacteria structure Bacterial classification How bacteria obtain genetic variation Uses and harmful effects of bacteria

Genetic Diversity in Prokaryotes Rapid reproduction Binary Fission Mutation 1 in 10 million chance of a mutation in each gene This leads to 9 million mutations in the E. coli present in your intestine Genetic recombination Transformation – taking up of foreign DNA Transduction – From bacteriophages Conjugation

Growth & Reproduction Binary Fission – bacterium doubles in size, it replicates its DNA and divides in half.

Transformation

Transduction

Conjugation F (fertility) plasmid – has genes for creating sex pili R (resistance) plasmid – contains antibiotic resistance genes

Major groups of bacteria Cyanobacteria - photosynthetic Chemosynthetic bacteria – nitrifying Nitrogen-fixing bacteria – live in nodules on plant roots Spirochetes – coiled, move in corkscrew motion, internal flagella

Cyanobacteria – blue-green algae

Non-oxygenic photosynthesis Bacteriochlorophylls H2S provide electrons Only 1 photosystem (PSI) Cyclic photophosphorylation

Importance of Bacteria Nutrient cycles Decomposition Oxygen production Food – baking & beverages Clean up oil spills, rivers & streams Make drugs Aid in digestion

Bacteria & Disease Pathogen – bacteria that cause disease or a disease causing agent. Exotoxins – toxic proteins secreted by bacterial cells, includes some of the most potent poisons known. Clostridium botulinum – one gram of the exotoxin that causes botulism could kill 1,000,000 people! Staphylococcus aureus – harmless, found on skin; if it enters the body through a wound it can cause layers of skin to slough off, vomiting, severe diarrhea & deadly toxic shock syndrome.

Bacteria & Disease Endotoxins – are NOT secretions; but components of cell walls in bacteria: glycolipids, which are large molecular complexes of polysaccharides & lipids. All endotoxins induce the same general symptoms: fever, aches and sometimes a dangerous drop in blood pressure (shock). Salmonella – produces endotoxins that cause food poisoning & typhoid fever.

Antibiotics Antibiotics are drugs that combat bacteria by interfering with various cellular functions Some bacteria are antibiotic-resistant and destroy antibiotics, or prevent entry of the antibiotic into the cytoplasm.

Microscope Lab Columns Look at Name Diagram Visible structures Prokaryotic or Eukaryotic Autotrophic or Heterotrophic Look at Bacteria Bacilli, cocci, spirilla 2 other bacterial slides of your choice Protist Pick 5 of them