1. Notes: Bacteria

2. General Characteristics
Microscopic, Exist everywhere
Unicellular
Prokaryotic (no nucleus or membrane bound organelles)
E. coli is a typical bacterium that lives in the human intestines.

3. Kingdom Archaebacteria
Found in extreme environments
Do not have peptidoglycan in cell walls
Instead have unique compounds in cell wall depending on species.
Examples:
Methanogens - in oxygen-free environments, like animals’ intestines - symbiosis
Halophiles – in concentrated saltwater
Thermoacidophiles – in hot, acidic waters of sulfur springs

4. Kingdom Eubacteria Ecologically diverse
Have peptidoglycan in cell walls.
Heterotrophs -
Decomposers
Parasites
Autotrophs -
Cyanobacteria: common in ponds, streams, and moist areas of land.

5. General Bacteria picture
Peptidoglycan
Cell Wall
Cell membrane
Ribosome
Pili
DNA
Flagellum

6. Basic Structure No membrane-bound organelles Small ribosomes
DNA - single circular chromosome
Cell wall (peptidoglycan)
Can be classified by shape & metabolism

7. Cell Shapes & Arrangements
Spheres: cocci (-us)
Rods: bacilli (-us)
Spiral: spirilla (-um)
Pairs: Diplo-
Cluster: Staphylo-
Chain: Strepto-

8. Name this bacterium
streptococcus

9. Metabolism Obligate aerobes require oxygen for cellular respiration
Obligate anaerobes no oxygen, produce energy thru glycolysis/fermentation
Facultative anaerobes can survive with or w/out oxygen

10. Growth & Reproduction Some divide every 20 min.
Pop. held in check by food availability & wastes produced

11. 1. Binary Fission
Asexual
Produces identical cells thru mitosis

12. 2. Conjugation
Sexual
Exchange genetic info new gene combos & bacteria diversity

13. Endospore Thick internal wall around DNA
Unfavorable growth conditions – heat, dry, no nutrients
Can remain dormant – years

14. Ecological Importance
Producers
Decomposers – recycle nutrients
Nitrogen fixers – ex. Soybeans
Sewage treatment

15. Human Importance Foods: Swiss cheese, pickles, yogurt
Medicines: antibiotics
Crops: nitrogen fixation, control pests
Digestion: E.coli

16. Antibiotics Kill bacteria by interfering w/metabolism Ex: penicillin,
streptomycin,
tetracycline, amoxicillin, zithromax, omnicef
Staphylococcus aureus & penicillium mold

17. How do bacteria make people sick?
1. Produce toxins that “poison” host cells
2. Bacterial cells crowd out healthy host cells.

18. Griffith’s Transformation Experiment
Pneumonia bacteria experiments
1928 – Fredrick Griffith
Had isolated 2 strains of bacteria
Smooth colonies – caused disease
Rough-edges colonies – no disease

19. 1

20. 2

21. 3

22. 4

23. Summary of Griffith’s Transformation
Mixing Rcells + heat-killed Scells causes a factor to transform the Rcells into Scells

24. Oswald Avery
Extracted “juice” from heat-killed S bacteria + enzymes to destroy proteins, lipids, carbs, & RNA  transformation still occurred
Extract + enzymes to destroy above & DNA  NO transformation
DNA = Factor causing transformation

25. Diseases Louis Pasteur Few kinds release toxins or damage cells
Ex: tuberculosis, botulism, strep throat & scarlet fever, tetanus, pneumonia, anthrax, meningitis

26. Controlling Bacteria Vaccines Antibiotics Sterilization Disinfectants,
Food Processing & Storage