Bacteria Prokaryotes Lack nucleus and membrane bound organelles Evolving on Earth for last 2.5 billion years Exist in variety of environments First organisms

How are bacteria classified? Previously only based on structure & physiology (Kingdom Monera) Currently rRNA sequences used to distinguish two different kingdoms

Two Kingdoms for bacteria Kingdom Archaebacteria – found in extreme environments Kingdom Eubacteria- bacteria you come in contact with every day

Kingdom Archaebacteria Found in extreme environments

Kingdom Archaebacteria Methanogens Anaerobic (Can’t live in O 2 ) Convert H 2 and CO 2 into Methane Swamps, sewage, guts of cows, termites Extreme Halophiles -salt loving salt beds Thermoacidophiles -live in hot, acidic environments Hydrothermal vents, hot springs

Kingdom Eubacteria Three Shapes Bacilli Cocci Spirilla

b Structure of Bacteria Capsule Cell Wall Cell Membrane Cytoplasm Capsules Ribosomes Pili DNA Flagella

Reproduction & Genetic Recombination Reproduces by binary fission Transformation-DNA from external environment Conjugation-Transfer of genetic info between 2 bacteria cells via the plasmid Transduction-virus carries DNA from one host bacterium to its next host

Useful Bacteria E. coli- lives in human intestinal tract Aids in break down of food different types of bacteria in your intestinal tract Food production- Yogurt, buttermilk, sour cream Streptococcus sanfranciscus Lactobacillus acidophilus Environmental Cleanup-oil spills Antibiotic production-Streptomycin

How do bacteria make you sick? Produce exotoxins – secreted proteins - causes dehydration Ex. Most bacterial infections Some release endotoxins when they die as cell wall breaks down Example typhoid fever and food poisoning

Bacteria and Disease Pathology is the study of disease Necrotizing fasciitis Staphylococcus infection

Antibiotics Antibiotics are drugs that combat bacteria by interfering with functions Penicillin-interferes w/ cell wall synthesis Tetracylcine-interferes with protein synthesis Erythromyocine-prevents protein Antibiotic Resistance-increase with increased use of antibiotics Steadily increasing since 1940’s Developed from some bacteria and molds, also chemically synthesized

Phylum Cyanobacteria Oldest bacteria Photosynthetic

Phylum Spirochetes Spiral shaped Aerobic bacteria = needs O 2 Ex. Syphilis, Lyme Disease

Phylum Gram-Positive Bacteria Source of some antibiotics Pathogenic- Ex. Strep throat

Phylum Proteobacteria Escherichia coli (E. coli) Largest & Most diverse group Some bacteria can convert chemicals in minerals into energy Some live in human intestinal tract