1. Bacteria

2. Key Characteristics Prokaryotic Unicellular
Range in size from 1-5 micrometers
can fit the diameter of a penny
Some move, some don’t
Some reproduce sexually, some asexually
Contain a cell wall

3. Two Groups of Bacteria Eubacteria Archaebacteria Live everywhere
Example – E. coli – human intestines
Surrounded by a cell wall made of peptidoglycan
Archaebacteria
Lack peptidoglycan in cell wall
DNA sequences are more like eukaryotes than eubacteria
Thought to be ancestral to eukaryotes
Most live in extremely harsh environments

4. Identifying Bacteria Shapes Groupings
Coccus (Cocci) – Spherical or round
Bacillus (Bacilli) – Rod
Spirillum (Spirilla) – Spiral
Groupings
“Diplo-” – paired
“Strepto-” – chains
“Staphylo-” - clusters

5. What shape is this?

6. What shapes can you find in this photo?

7. How Do They Move?
Some bacteria have flagella, which is a whip-like structure that acts as a tail
Some move by lash, snake, or spiral movements
Some excrete a slime-like material that it used for gliding

8. Notice their tails?

9. Metabolic Diversity Some are heterotrophic – have to eat
Some are autotrophic
Photoautotrophs – Photosynthesis
Chemoautotrophs – Chemosynthesis

10. Releasing Energy - Respiration
Obligate Aerobes
Require a constant supply of oxygen for survival
Mycobacterium tuberculosis
Obligate Anaerobes
Require the absence of oxygen for survival
Clostridium botulinum – food poisoning
Facultative Anaerobes
Can survive in the presence and absence of oxygen  perform both cellular respiration and fermentation
E. coli

11. Mycobacterium tuberculosis

12. Clostridium botulinum
Did you know that this is the same stuff they put in Botox injections?

13. Escherichia coli

14. Growth and Reproduction
Binary fission
Asexual reproduction
One bacterium replicates its DNA and divides in half, producing 2 identical cells
Conjugation
Sexual reproduction
Exchange of genetic information
Spore formation (endospores)
When growth conditions are unfavorable, bacteria form spores, which can remain dormant for months or years while waiting for more favorable growth conditions

15. Binary Fission

16. Conjugation

17. Importance of Bacteria
Decomposers
Help recycle nutrients
Break down dead tissue
Help in sewage treatment
Nitrogen fixers
Convert nitrogen gas into a form of nitrogen that plants can use
Human uses
Production of many foods and drinks
Help clean up oil spills – can digest petroleum
E. coli – lives in human intestines – produces vitamins the body can’t produce on its own