1. Bacteria
Biology 11

2. Prokaryotic Cells Unicellular No nucleus No membrane-bound organelles
Do contain DNA

3. 2 Kingdoms Archaebacteria “ancient bacteria”
Eubacteria “true bacteria”

4. Archaebacteria: The Extremists
Live in harsh environments

5. Methanogens: Produce methane Live in oxygen free environments
Found in swamps, marshes, stomachs of cows
Sewage disposal plants- help breakdown sewage

6. Halophiles: Salt-loving
Live in salt pools left after a lake has evaporated
pools have high levels of magnesium and potassium salts
Utah’s Great Salt Lake and Middle East’s Dead Sea

7. 3. Thermoacidophiles: Heat- and acid-loving
Live around deep ocean vents
Temperatures are often above 100ºC
Anaerobic (without oxygen)
Live in hot, acidic waters of sulfur springs

8. Eubacteria Live everywhere except extreme environments Heterotrophs
Use organic molecules as food source
Some are parasites
Some are saprophytes (feed on dead organisms or organic wastes – break down and recycle nutrients)

9. 2. Photoautotrophs
Photosynthetic autotrophs - Live in places with sunlight
Cyanobacteria – contain chlorophyll (pigment) that traps the sun’s energy
Live in ponds, streams, and moist areas of land
Composed of chains of independent cells

10. 3. Chemoautotrophs
Make organic molecules
Obtain energy by breaking down compounds with sulfur and nitrogen and releasing the energy in the process called chemosynthesis
Bacteria in Plants– able to convert atmospheric nitrogen into the nitrogen-containing compounds that plants need

11. Bacteria Structure Ribosomes- protein synthesis
Chromosome- single circular DNA molecule
Cell Wall- support and protection
Flagella- motility

12. Pilli (sing. Pillus) hair like structure to aid in reproduction and attaching to one another
Capsule- sticky, gelatinous, surrounds cell wall to protect against desiccation
Cytoplasm- thick liquid within cytoplasmic membrane
Plasmid- small circular piece of DNA

13. If Bacteria don’t have mitochondria, how do they get their energy?
Occurs at cell membrane

14. Identifying Bacteria
Bacteria are separated into two groups based on characteristics of cell wall
Cell walls made of peptidoglycan (sugar and amino acid molecules) which helps structure and maintain shape (target for antibiotics)
Technique called gram staining is used to do this

16. Gram Stain
First, crystal violet dye is added. Then, a second dye is added.
Gram + bacteria retain crystal violet dye
Gram – bacteria appear red or pink after a counterstain is added (commonly safranin)

17. Gram-positive: one thick layer of peptidoglycan (protein and sugar)
Gram-negative: one thin layer of peptidoglycan and an outer lipid and sugar layer

18. Identifying Bacteria Growth pattern Diplo (paired arrangement)
Bacteria shape (plural)
Cocci (spheres)
Bacilli (rods)
Spirilla (spirals)
Growth pattern
Diplo (paired arrangement)
Staphylo (grape arrangement)
Strepto (chain of cells)

19. Strepto-Coccus

20. Strepto-Bacillus

21. Spirillum

22. How do bacteria get around?
Flagella vs Cilia
Flagella use whip like motions to move
Cilia use a beating motion to move (eukaryotes only)

23. Remember: Bacterial DNA Circular
Free floating in the bacterial cytoplasm

24. A well fed bacteria is two happy bacteria
ATP- when used, turns into ADP (Tri-phosphate or Di-phosphate)
Bacteria have a protein called DnaA that starts the process of DNA replication (first step in fission)
DnaA+ADP = nothing  ; DnaA+ATP = replication

25. Bacteria Reproduction
1. Asexual by binary fission
DNA replicated
DNA pulled to separate poles as bacterium increases in size
A partition forms and separate the cells
Results in genetically identical cells
Can be rapid –ideal conditions every 20 minutes

27. Plasmids Extra circle of DNA that can replicate independently
Can be transferred to another Bacterium
Typically carries a beneficial trait. e.g. antibiotic resistance.

29. 2. Conjugation
Bacteria conjugate if one of them have special “F” factor (fertility factor)
The F+ bacteria (donor) makes a Pilus, and transfers the F plasmid to the F- recipient.
Recipient is now F+
Results in a bacteria with new genetic composition

31. Spore Formation
Endospore: tiny structure that contains a bacterium’s DNA and a small amount of its cytoplasm
Encased by tough outer covering
Resists drying out, extreme temperature, harsh chemicals
If environmental conditions improve, then endospore germinate
To kill endospores, items must be sterilized (i.e. heated under high pressure)

33. Metabolism 2 Types: Aerobic and Anaerobic
Aerobic Bacteria require oxygen to produce energy
Anaerobic Bacteria don’t require oxygen to produce energy

34. When typing Bacteria- Gram’s stain is #1, then comes how they make energy
Obligate Anaerobic (Can’t live with oxygen)
Facultative Anaerobic (can get by either way)
Obligate Aerobic (Can’t live without oxygen)

35. Where can they get energy from?

36. Importance of Bacteria
Ecological Role
Production of nutrients
Nitrogen fixation
Vitamin K, B12
Breakdown of cellulose
Breakdown of detritus
Prevention of pathogen colonization

37. Production of Nutrients
Soil microbes take nitrogen from atmosphere and make nitrogen containing compounds (nitrates, nitrites, etc)
Some exist in symbiotic relationships (eg. Termites, legumes, clover, alder, etc)

38. Some bacteria produce Vitamin K (E
Some bacteria produce Vitamin K (E. coli) or B12, which are not produced anywhere else

39. Cellulose (plant fibers) cannot be broken down by eukaryotes
Many organisms exist in symbiotic relationships with bacteria in order to break down cellulose into usable sugars.

40. Break down of detritus Bacteria clear landscape of dead matter
Returns nutrients to the soil

41. Prevention of colonization
Take up valuable real estate that pathogenic organisms would love to inhabit
Harmless or beneficial bacteria prevent harmful ones from colonizing