A. General Information Structure: 1.

A. General Information
1. Structure:
A. prokaryotic (no nucleus)
B. uni-cellular
C. cell walls,
D. genetic code = DNA , single circular chr.
2. Ecological Roles:
A. Decomposition
B. Nitrogen Fixation
3. Ubiquitous = they are everywhere
4. Most diverse habitats of all living organisms
5. 2 kingdoms:
Eubacteria and Archaebacteria
C. Structure
1. 2 types of Cell wall
– can be identified by Gram Stain reaction
a. Gram positive (positively purple)
THICK layer of peptidoglycan (protein)
in cell wall
Gram Positive Bacteria
b. Gram negative (pink) THIN layer of
petidoglycan in cell wall
Gram Negative Bacteria
Gram stain tells which antibiotics will
work against it
Gram Positive vs. Gram Negative Bacteria
2. Capsule – may or may not be present(have capsule = antibiotics do NOT work
as well)
Bacterial Capsule
3. Pili
a. Short hair-like projections
b. f(x)s=
1). attachment to host
2). conjugation (sexual reproduction)
Bacterium Diagram
4. Endospores
a. formed under STRESS (bad conditions)
b. Thick walled outside with DNA inside
c. Can grow after many years
(some 1300 yr. old anthrax spores grew)
Bacterial Endospore
5. Shapes
a. Coccus– spherical
cocci (plural)
b. Bacillus-rod-shaped
bacilli (plural)
c. Spirillum- spiral shaped
spirilli (plural)
6. Groupings of Bacteria
a. diplotwo
b. streptochain
c. staphylocluster / clump
Groupings of Bacteria
7. Bacterial Reproduction
a. Asexual- binary fission
 only 1 needed
 no genetic diversity
 good for rapid repopulation
Bacterial Binary fission
b. Sexual - conjugation
 takes two
 genetic diversity
 allows bacteria to transfer antibiotic
resistance between species
8. Classification of Bacteria
a. Gram Staining
b. Shape & Groupings
c. How they obtain ENERGY
1). Photosynthetic
eg. Anabena fixes nitrogen into the soil
2).Chemo – autotrophic (“eat”
 Some “eat” : NH3 (ammonia)
H2S (hydrogen sulfide)
Sulfide –eating bacteria
 Some make CH4 (methane)
3). Heterotrophic (“other” feeding) eat others
4). Aerobes - must have oxygen
5). Anaerobes - oxygen kills them
eg. Clostridium tetani
Clostridium botulinum (botulism)
6). Faculative anaerobes –
can live with or with out oxygen
9. Controlling Bacteria
a. Antibiotics
1). How do they work?
Rupture cell walls or prevent protein synthesis
2). Increases animal life expectancy
 Greatly reduces the infant mortality rate
 Fight diseases, save lives
b. Sterilization
1). Heat kills bacteria
2). Chemicals used to kill bacteria
c. Food Handling &Processing
1). Keep foods cold enough or hot enough to
prevent bacterial growth
(cook, steam, boil, freeze)
2). Can / preserve with:
salt, sugar, vinegar, & heat )
d. Irradiation for preservation
10. How are bacteria pathogens?
(disease causing agent)
a. Metabolise (eat) or lyse (blow up) host cells
(cell, tissue damage)
b. Secrete toxins (poisons)
c. Food poisoning examples
1). Salmonella - undercooked chicken, eggs
2). Staphylococcus aureus - wrestling mats
3). Clostridium botulinum - canned goods
4). Eschericia coli - undercooked beef
11. Helpful Bacteria
a. Food production eg. yogurt, cheese, pickles,
sauerkraut, wine, vinegar, olives
b. Industrial/ other uses
 Mining
 Oil spill clean up (bioremediation)
 Water purification
Water treatment plant
 Synthesis of drugs & other genetic
engineering e.g. insulin
 Snow making (helps tourism)
Snow making
c. Symbiosis
 Cellulose digesters in cattle guts
Cows grazing
 E. coli in human large intestine
E. coli in your gut helps digest food and make vitamins
 Nitrogen fixation on plant roots (legumes)
(plants need nitrogen to live! & all animals
need plants to live…)
12. Harmful bacteria
a. Pathogens e.g. strep, tetanus, bubonic plague,
anthrax, smallpox, Lyme disease
b. Food poisoning e.g. Salmonella, Staph,
Botulism, E. coli
13. Eubacteria (most of the bacteria we know)
14. Archaebacteria (the EXTREME BACTERIA)
a. Thermophiles – heat tolerant e.g.
Near undersea volcanic vents
Thermophilic Bacteria
Halophilic bacteria
b. Halophiles – salt tolerant
e.g. Great Salt Lake is 10-15% NaCl