1. Monera Part 2

2. Gram Stain Procedures 1.
3a.
3b. 2.
DYE-
Crystal
Violet

3. Counterstain to see the
Gram Stain Procedures 4. 5.
Counterstain to see the
gram - bacteria
After the alcohol wash,
Gram + = purple
Gram - = colourless

4. Examples
Yoghurt Bacteria
(Lactobacillus and Streptococcus)

5. E.coli

6. A mixture

7. Based on your knowledge
Can you tell which type of bacteria is more resistant to drugs? - +

8. More Gross Infections For You

9. Other ways to Classify Bacteria
Presence or Absence of a Slime Capsule:
Protects against dryness
Increases virulence
Movement

10. Other ways to Classify Bacteria
Energy & Nutrition Requirements:
Autotrophs (make their own food)
Phototrophic Autotrophs
Obtain energy from SUNLIGHT
ex. Cyanobacteria
Chemotrophic Autotrophs
- Obtain energy from INORGANIC molecules like H2S and NO2
ex. Rhizobium – nitrogen fixation (p.372) (make N useable for plant)
photosynthesis

11. Other ways to Classify Bacteria
Heterotrophs (more efficient)
Chemotrophic Heterotrophs
- Obtain carbon from ORGANIC compounds
ex. Salmonella
ii. Phototrophic Heterotrophs
- Obtain energy from sunlight but need ORGANIC molecules for nutrition

12. Feed on
organic
molecules

13. Other ways to Classify Bacteria
Oxygen Requirements:
Obligate aerobe
– require O2 (breathing)
Obligate anaerobe
– must live in absence of O2
(O2 kills them - fermentation)
Facultative anaerobe
– can live with or without O2

14. Other ways to Classify Bacteria
D) Bacterial Reproduction:
Binary Fission
asexual form of
reproduction in bacteria
DNA replicates
and cell pinches into two

15. Conjugation Form of sexual reproduction in some bacteria
Protein bridge called a pilus forms between 2 bacteria and genetic information is transferred from 1 cell (the donor) to the other cell (the recipient)
Advantage  new genetic combination  more resistant

16. Endospores (inside, pockets)
Formation of hard resistant spores when conditions are hostile (too dry, too hot)
An internal wall forms around the DNA and part of the cytoplasm
Can last for months
When favourable conditions return binary fission resumes
Technically not reproduction but allows bacteria to survive through harsh conditions

17. Conditions Required for Growth
Temperature (usually warm)
Moisture
Light
Ample food (more than enough)
Right pH (acidity) level
Oxygen or Oxygen free

18. Growth Curve of Bacteria p. 379
Wastes buildup
Food is depleted
Bacteria die
Lots of food
good condition
rapid growth
Bacteria compete for food
# stabilize (Death = Birth)
Limit to carrying capacity of
environment
Slow growth:
bacteria adjusts
to environment

19. Bacteria and Us Food products - cheese - fermented dairy products
- yoghurt, buttermilk
- pickles, sauerkraut
- vinegar and wine
Others
- antibiotics (Erythromycin)
- digest petroleum (cleaning up oil spills)
- dyes (able to make indigo for jeans)
- vitamins (K – in the human body)

20. Ecological Roles of Bacteria
Symbionts
Symbiosis: a close relationship with another organism in which the bacteria and organism both benefit
Ex. E.coli
Decomposers
Recycle (break down) dead material
Saprophyte: organisms that use complex molecules of once-living (dead) organism as their source of energy and nutrition

21. When a Tree Dies Tree dies and falls Insects and bacteria
Wood softens and bark peels off
Tree crumbles into soil

22. Ecological Roles of Bacteria
Sewage Treatment
Decompose material in waste water
Waste water: human waste, discarded food, organic garbage, and chemical waste
Produce
purified water
Nitrogen gas
CO2

23. Ecological Roles of Bacteria
Nitrogen Fixation
All organisms are dependent on bacteria for nitrogen
Plants use nitrogen to produce AAs
But atmospheric nitrogen is not usable to plants
Bacteria fix N2 to NH3