1. BACTERIA NOTES

2. Cellular Evolution – Prokaryotes and Eukaryotes
Current evidence indicates that eukaryotes evolved from prokaryotes between 1 and 1.5 billion years ago
Two theories:
1. Infolding theory
2. Endosymbiotic theory

3. Infolding Theory
The infolding of the prokaryotic plasma membrane gave rise to eukaryotic organelles.
infolding
organelle

4. Endosymbiotic Theory
Endosymbiosis refers to one species living within another(the host)
Movement of smaller photosynthetic & heterotrophic prokaryotes into larger prokaryotic host cells
Formed cell organelles
chloroplast
mitochondria

5. Prokaryotes - Bacteria
Unique Characteristics:
Microscopic prokaryotes
Small ribosomes
Single, circular chromosome (DNA) in nucleoid region

6. Size of Bacteria

7. Three Domains of Life Archaea – prokaryotes living in extreme habitats
Bacteria- Cyanobacteria and eubacteria
Eukarya – Protozoans, fungi, plants, & animals

8. Bacteria Kingdoms Eubacteria Archaebacteria Most common
Found everywhere
First living cells (?)
Photoautotrophs
Contain chlorophyll but not inside a chloroplast
Withstand hostile environments
Nicknamed “extremophiles”

9. Archaebacteria vs. Eubacteria

10. Classification OF BACTERIA - based on shape

11. Shapes Are Used to Classify
Bacillus: Rod shaped
Coccus: Spherical (round)
Vibrio: Comma shaped with flagella
Spirillum: Spiral shape
Spirochete: wormlike spiral shape

12. Grouping of Bacteria - Prefixes
Diplo- Groups of two
Strepto- chains
Staphylo- Grapelike clusters

13. Diplococcus

14. Streptococcus - Causes Strep Throat

15. Staphylococcus

16. Bacillus - E. coli

17. Streptobacilli

18. Spirillum and Spirochetes – Lyme Disease and Syphilis

19. Bacillis anthraxis
Mycobacterium tuberculosis
Actinobacillis bacterium

20. Classification based on cell wall
Uses Gram staining
Named for a Danish bacteriologist, Gram staining is a technique for the identification of bacteria in which a violet dye is applied.

21. Gram Positive Gram Negative
Thick cell wall made of peptidoglycan (protein-sugar complex)
Retains purple stain
Antibiotics keep cell walls from forming correctly
Cells die
Gram Negative
Thinner cell walls
Stain washes away
Antibiotics won’t work

22. EXAMPLES Gram Negative Gram Positive
Rhizobacteria - grow in root nodules of legumes (soybeans, peanuts)
Fix N2 from air into usable ammonia (NH3) (nitrogen fixation)
Rickettsiae -parasitic bacteria carried by ticks
Cause Lyme disease & Rocky Mountain Spotted Fever
Lactobacilli (makes yogurt & buttermilk)
Actinomycetes (make antibiotics)
Clostridium (lockjaw bacteria)
Streptococcus (strep throat)
Staphylococcus (staph infections) 22

23. Bacteria Obtain and Use Energy
Heterotrophs: don’t make own food
Saprobes – feed on dead organic matter
Parasites – feed on a host cell
Autotrophs: can make own food
Bacteria can be “photoautotrophs” or chemoautotrophs”

24. Cyanobacteria Gram negative, photosynthetic Called blue-green bacteria
Contain phycocyanin (red-blue) pigments & chlorophyll - may be red, yellow, brown, black, or blue-green
May grow in chains (Oscillatoria)
First to re-enter devastated areas
Some cause Eutrophication (use up O2 when die & decompose in water)

25. Types of cellular Respiration in bacteria
Obligate Aerobes – require O2 (tuberculosis bacteria)
Obligate Anaerobes – die if O2 is present (tetanus)
Facultative Anaerobes – don’t need O2, but aren’t killed by it (E. coli)
Anaerobes = carry out fermentation
Aerobes = carry out cellular respiration

27. BACTERIAL Reproduction
Bacteria reproduce asexually by binary fission
Single chromosome replicates & then cell divides
Rapid; All new cells identical (clones)

28. Binary Fission (asexual reproduction)

29. Endospores
Form endospore whenever when habitat conditions become harsh (little food)
Able to survive for long periods of time as endosperm
Difficult to destroy (heat resistant)

30. Conjugation (sexual reproduction)
A tube forms between 2 bacteria to exchange genetic material
Held together by pili
New cells NOT identical
Pilus

31. Beneficial Uses of Bacteria
Food: yogurt, cheese, soy sauce
Symbiotic Relationships: E.coli in intestines, nitrogen fixation
Recycling Nutrients: sewage
Industrial: oil spills, mining
Medicine: antibiotics, genetic research