1. Bacteria

2. Eubacteria Larger of two bacteria kingdoms Live almost everywhere
Many types of metabolism
Heterotrophs
Photosynthetic Autotrophs
Chemosynthetic Autotrophs
Cell walls contain peptidoglycan, a carbohydrate

3. Archaebacteria Lack peptidoglycan in their cell walls
Different membrane lipids
DNA sequence is different
Live in extremely harsh environments
Oxygen-free
Concentrated salt water
Hot springs

4. Identifying Prokaryotes
Prokaryotes are identified by characteristics such as:
Shape (round, rod, spiral)
Chemical nature of cell walls (Gram – or +)
The way they move (none, flagella, slime)
The way they use energy

5. Bacterial Shapes and Arrangements

6. Gram Stain Procedure

7. Diversity of Metabolism
Heterotrophs (most)
Autotrophs (some)
Photoautotrophs
Chemoautotrophs
Obligate aerobes
Obligate anaerobes
Facultative anaerobes

8. Bacterial Growth and Reproduction
In favorable conditions, some bacteria divide as often as every 20 minutes!
If unlimited space and food were available to every bacterium, in 48 hours they and their offspring could reach a mass of 4000x the mass of Earth!
Fortunately, availability of food and the production of waste products keeps bacterial growth in check.

9. Bacterial Reproduction
Bacteria reproduce asexually through a process called binary fission.
Many bacteria also have a simple form of sexual reproduction called conjugation.

10. Endospores
Hard outer coverings called endospores are formed by many bacteria when they face unfavorable environmental conditions.
Endospores are resistant to drying out, boiling, and many chemicals.
They can remain dormant for months or even years!
                                               

11. Bacteria are “Survivors!”
Some of the oldest known fossils are of bacteria
Broad variety of metabolic pathways
Endospores
Asexual and sexual reproduction
                              

12. Importance of Bacteria
Nitrogen fixation
Decomposition
Photosynthesis
Foods: vinegar, yogurt, butter, cheese, pickles, etc.
Synthesize drugs and chemicals
Make vitamins
Digest petroleum

13. Review Question #1
How are are eubacteria and archaebacteria alike and different?

14. Review Question #2
Describe some adaptations of bacteria.

15. Review Question #3
Bacteria are essential to life. Why do you think this statement is true?