1. EUBACTERIA and ARCHAEBACTERIA pp.360-372

2. Classifying Prokaryotes
All prokaryotes were once placed in the Kingdom Monera.
Recently, biologists divided them into two different kingdoms: the Eubacteria and the Archaebacteria.

3. Eubacteria Archaebacteria
No peptidoglycan in cell walls
Live in extreme environments
Thermophiles, halophiles, methanogens
Peptidoglycan in cell walls
Cannot survive in extreme environments
Bacteria & cyanobacteria
Prokaryotic
No nucleus
Single-celled
Ribosomes
No membrane-bound organelles

4. Archaebacteria 
DNA shows a closer evolutionary relationship to eukaryotes
Many archaebacteria live in extreme environments.
Methanogens live in oxygen-free environments (ex. thick mud & animal digestive tracts)
Halophiles live in salty environments
Thermophiles live in hot environments (ex. hot springs)

5. 2. Eubacteria
Eubacteria have a cell wall that protects the cell and determines its shape.
Live everywhere:
in fresh and salt water
on land
in the human body

6. E. coli, a Typical Eubacterium
(Peptidoglycan)
A bacterium such as E. coli has the basic structure typical of most prokaryotes: cell wall, cell membrane, and cytoplasm. Some prokaryotes have flagella that they use for movement. The pili are involved in cell-to-cell contact. The cell walls of eubacteria contain peptidoglycan.

7. Types of Eubacteria Bacilli = rod-shaped Cocci = spherical-shaped
Spirilla = spiral & corkscrew-shaped
Prokaryotes can be identified by their shapes. Photo Credit: ©David Scharf/Peter Arnold, Inc.

8. Arrangement or Grouping
Paired = diplo
Filamentous (chains) = strepto
Colonial (grape-like clusters) = staphylo

9. Identifying Prokaryotes:
Two different types of cell walls are found in eubacteria.
A method called gram staining tells them apart.
Gram-positive bacteria have thick cell walls with large amounts of peptidoglycan.
Gram-negative bacteria have thinner cell walls inside an outer lipid layer.
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10. Mobility Some have one or more flagella
Some lash, snake or spiral forward
Some glide on a layer of slime-like material

11. Copyright Pearson Prentice Hall
Nutrition
Prokaryotes can be heterotrophic or autotrophic.
Energy is released by cellular respiration (aerobic) or fermentation (anaerobic) or both
1. Obligate aerobes require oxygen
2. Obligate anaerobes live without oxygen because they may be killed by it
3. Facultative anaerobes can survive with or without oxygen
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12. Reproduction - Asexual
Binary fission
Most common
When bacterium is near double in size, bacterial cell replicates its DNA and divides in half, producing two identical daughter cells.
Ex) E. coli

13. Genetic exchange Conjugation
Protein bridge forms between 2 bacterial cells
One bacterium transfers some/all of its DNA to the other cell
Results in recipient bacterial cell with new genetic variation
Recipient bacterium will then undergo binary fission

14. Spore Formation
In unfavorable growth conditions, an endospore can form
the bacterium produces a thick internal wall that encloses its DNA and some of its cytoplasm.