I. General characteristics
A. Most are single celled (there are multicellular cyanobacteria)
B. Heterotrophic and autotrophic
A. Page 431 figure 21-4 (Curtis)
1. Not all bacteria have flagella or capsules (slime layers)
A. Domain Archaea
1. Chemoautotrophs - thermoacidophiles (love hot and acid), methogens, extreme
halophiles (love salt).
B. Domain Eubacteria
1. Cyanobacteria and most other bacteria.
C. Eubacteria are classified according to shape, arrangement and chemical activity.
1. There are three basic shapes & three different arrangements. Page 429 (Curtis)
a) Coccus (i) = spherical shape
(1) single cocci, diplococci, streptococci and staphylococci
b) Bacillus (i) = rod shaped
(1) single bacillus, diplobacillus and streptobacilli.
(a) Strep throat is caused by a streptobacillus.
c) Spirillum (a)
A. Many forms have flagella for movement.
B. Many have a sticky capsule (slime layer) that allows them to attach to their food.
A. Some produce toxins
B. Most are protected by numbers.
VI. Feeding and digestion
A. Bacteria secrete enzymes that digest their food and then they absorb the food back into
B. Is this intra- or extracellular digestion?
VII. Classified according to living arrangements.
A. saprophytic organisms
1. live on dead things
2. Know the difference between a saprophyte and scavenger
1. Parasitic organisms
a) Neisseria gonorrhea
2. Mutaulistic organisms
a) Many of the digestive tract bacteria produce some of the B vitamins and
3. Commensalistic organisms
a) The bacteria living on your skin.
VIII. Growth requirements for bacteria
A. Proper temperature
1. they like it warm, optimum range is between 26-38ºC
2. But some forms live at below 0ºC and as high as 95ºC.
B. Must have moisture
C. They grow best in the dark.
1. UV light kills bacteria
D. Must have food (Type of food depends on organism)
IX. Circulation & excretion are accomplished by diffusion
A. Obligate aerobes
1. must have oxygen to live
2. Mycobacterium tuberculosis
B. Obligate anaerobes
1. Can not live in the presence of oxygen
2. Clostridium botulinum
C. Facultative anaerobes
1. Can grow with or without oxygen
2. e.g. Escherichia coli
A. Binary fission
B. Conjugation - bacteria can exchange DNA through small extensions called pili.
XII. Harmful effects of bacteria
A. Cause diseases and disorders
1. Botulism, Tuberculosis and Gonorrhea Neisseria gonorrhoeae
B. Other problems caused by bacteria
1. Food spoilage (many species)
2. Food poisoning Salmonella sp.
3. Boils, pimples, pneumonia, and meningitis, are all caused by different strains of
C. **Know how microbes cause disease** page 448 in Curtis
D. Understand the role of antibiotics in treating bacterial diseases.
XIII. Beneficial effects of bacteria
A. Used to produce food: Yogurt, Cottage cheese, Blue cheese and Vinegar
B. Tanning of leather and Curing tobacco
C. Recycle dead organisms
D. Used as a tool in genetic engineering
E. Nitrogen fixation