1. Classifying Prokaryotes

2. The Tree of life

3. Bacteria are prokaryotes….But what is a prokaryote?

4. Prokaryote
Eukaryote

5. Prokaryotes are microscopic with no nucleus
They are the most ancient (oldest) and most numerous organisms on the planet.
There are 2 Kingdoms:
ARCHAEBACTERIA
EUBACTERIA

6. Kingdom Archaebacteria
“Archae” means “ancient” bacteria
They are “extremists”
Methanogens: live in oxygen-free environments
 anaerobic conditions
 convert H2 & CO2 into methane gas
Thermoacidophiles: live in water that is extremely HOT (230º F) and ACIDIC (pH < 2).
Halophiles: live in extremely SALTY conditions

7. HALOPHILES
THERMOACIDOPHILES
METHANOGENS
THERMOACIDOPHILES
METHANOGENS

8. Archaebacteria Many live in extremely harsh environments
Methanogens live in oxygen-free environments
Others in extremely salty environments (Great Salt Lake) Halophile
Hot springs where temperatures approach the boiling point of water

9. “ExTrEmE!” halophiles (e.g., salt flats) methanogens (e.g., anaerobic)
salt ponds
halophiles (e.g., salt flats)
methanogens (e.g., anaerobic)
thermophiles (e.g., hydrothermal vents)
Answer to question: If they are looking for life on other planets – they might encounter extremophiles or remains of extremophiles in harsh environments of those planets.
Thermus aquaticus
hot springs
Extremophiles, “lovers” of extreme environments. 9

10. Kingdom Eubacteria Heterotrophs: Energy from organic matter
“TRUE” bacteria – (most bacteria)
Classified according to how they obtain energy
Heterotrophs: Energy from organic matter
Parasitic: energy from living organisms
Saprobes: feed on dead organisms
Phototrophic Autotrophs
Energy from light
Chemotrophic Autotrophs
Energy from breakdown of inorganic compounds

11. Eubacteria The larger of the two classifications.
Live almost everywhere: Fresh water, salt water, on land and on and within the human body.

12. Archaebacteria
Eubacteria

13. Characteristics/Comparison
Bacteria & Archaea
Unicellular
Prokaryotes (no membrane-bound nucleus)
Smaller than Eukaryotic cells
Domain Bacteria
Peptidoglycan cell walls
Plasma membrane similar to Eukarya
Unique ribosomes
Don’t have students copy – focus on graphic showing that all started in one place and evolved.
Domain Archaea
Polysaccharide cell walls
Unique plasma membrane
Ribosomes similar to Eukarya 13

14. Bacteria Classification

15. Structure of Bacteria Bacteria are classified by 2 characteristics:
Arrangement
Shape

16. Cell Wall
Determines shape. Some have a second membrane outside the cell membrane that makes them especially resistant to damage.

17. SHAPE

18. Shapes bacillus- rod shaped coccus- circular
in chains called streptococci
in clusters called staphylococci
spirillum- spiral-shaped

19. Grape-like clusters: staphylo Chains: strepto
Arrangements
Paired: diplo
Grape-like clusters: staphylo
Chains: strepto

20. Examples Streptococcus: Chains of spheres Staphylospirillum:
Grapelike clusters of spirals
Streptobacillus:
Chains of rods

21. Bacteria Cell Structure
cell wall: peptidoglycan
chromosome: single; circular
pili: hair-like structures
* conjugation
* cell-to-cell contact
flagella: whip-like structure
* locomotion
capsule: sticky “coat”
* extra protection

22. Flagella
Motility - movement

23. Endospores
Structure in some bacteria that is resistant to adverse environmental factors.
Boiling >1 hr still viable

24. Gram Stain Gram Positive- turn purple from gram stain
Gram-Negative- Do not take on purple and turn pink (Resistant to Antibiotics)

25. Eubacteria: Chemotrophic Autotrophs
Get energy by breaking down inorganic substances like sulfur and nitrogen
Make nitrogen in the air usable for plants {Very Important}

26. Lactic Acid Fermentation
Fementative bacteria that produce lactic acid under anaerobic conditions. Release energy by producing ATP in the absence of oxygen.
Dairy industry
cheese, cottage cheese, yogurt
Alcoholic Fermentation
Produces carbon dioxide as well as alcohol.
-- causes bread dough to rise. 26