1. CHAPTER 19 NOTES
BACTERIA

2. CHARACTERISTICS OF BACTERIA
Prokaryotic or Eukaryotic: Prokaryotic
Unicellular or Multicellular: Unicellular
Autotroph or Heterotroph: Autotrophs and Heterotrophs
Which Kingdom do they belong in? Eubacteria & Archaebacteria
Examples: bacteria, methanogens & halophiles, cyanobacteria (autotroph)

3. TYPICAL BACTERIUM
CELL MEMBRANE
CYTOPLASM
FLAGELLA
DNA
CELL WALL
PILI

4. Most Bacteria reproduce by one of 3 means:
1. Asexually
Also known as binary fission in which the chromosome replicates and then the cell divides
This produces 2 identical cells
2. Sexually
Also known as conjugation in which genetic material is exchanged through cell-to-cell contact
This increases the genetic diversity of bacteria

5. Most Bacteria reproduce by one of 3 means:
3. Spore Formation
When living conditions become unfavorable, some bacteria can form dehydrated cells known as endospores
Endospores have thick walls and can resist heat, drought and radiation and thus they can survive harsh conditions
When conditions improve, the spore will germinate and bacteria will grow again

6. HOW ARE BACTERIA CLASSIFIED?

7. Bacteria are divided into 2 main groups:
1. Archaebacteria
Found living in harsh environments, like hot springs, near undersea volcanic vents and in highly salty water
These bacteria are further divided based on the environments in which they live
2. Eubacteria
Include all the organisms commonly called bacteria
Live in much less harsh environments

8. Bacteria can also be classified by their shape:
1. Cocci
Sphere-shaped
2. Bacilli
Rod-shaped
3. Spirilla
Spiral-shaped

9. Bacteria can be classified by their cell wall differences:
The technique to see these differences is called GRAM STAINING
1. Gram-positive (looks purple)
2. Gram-negative (looks red)

10. Other ways to identify Bacteria
By their Nutrition
1. Autotroph
Ex. Cyanobacteria
2. Heterotrophs
Ex. Bacteria
Based on Respiration
1. Aerobes- need oxygen during respiration
2. Anaerobes – do not use oxygen during respiration

11. IMPORTANCE OF BACTERIA

12. ECOLOGICAL ROLES
1. Bacteria act as decomposers, which means they break down dead organic materials
2. They also help recycle carbon, nitrogen and sulfur and other chemicals needed by living things
3. Many bacteria live with organisms of other species in a relationship called symbiosis
bacteria in your mouth (bacteria benefit & you are harmed)
bacteria in cow intestines (bacteria benefit & cow benefits)
E. coli, a bacteria found in human intestines, helps with the process of digestion

13. DISEASES CAUSED BY BACTERIA
Some bacteria cause diseases in humans
Some examples are:
Tuberculosis, anthrax, lyme disease, strep throat, cholera
Antibiotics can kill harmful bacteria if used properly

14. HUMAN USES OF BACTERIA
Bioremediation – use of microorganisms to help restore natural environmental conditions; ex. Sewage treatment plants
Bacteria are used in the production of many foods; some examples are: cheese, yogurt, vinegar, beverages
Bacteria have applications in medicine; some bacteria have been genetically engineered to produce insulin