1. Bacteria

2. Quick Quiz True or False
 1. 600 different kinds of bacteria live on your skin.
 True
 2. Saliva contains 30 different kinds of bacteria.
 False; 6
 3. Most bacteria multiply using the process of binary
fission.
 True
 4. You can see, taste, and smell bacteria.
 False; cannot see with naked eye
 5. Leaving foods at room temperature will slow
bacterial growth.
 False; Place in cold environments
 6. There are more microbes on your body than there
are humans on the entire planet.
 True.

3. True / False con’t
 7. Bacteria help our bodies with digestion and
produce
 True: E. coli makes vitamin K and B12
 8. Bacteria are used to make chocolate.
 True; it helps digest the hard outer covering
of the bean
 9. Only 50% of all bacteria are helpful.
 False; 99%
 10. The four shapes of bacteria are circular,
square, rod, and spiral.
 False; No square

4. Prokaryotes vs. Eukaryotes
 Prokaryotes  Eukaryotes
 No true Nucleus  Membrane bound
 No membrane nucleus
bound organelles  Membrane bound
 Small organelles
 Simple  Larger
 Evolved 3.5 bya  Complex
 Evolved 1.5 bya

5. Bacteria
 Can be found almost everywhere on
Earth.
 Earliest known fossils 3.5 bya
 Oldest group of organisms
 All bacteria are prokaryotes
 2 main groups (kingdoms)
Eubacteria
Archaebacteria

6. EUBACTERIA / TRUE BACTERIA
 Most common today
 Cause disease & decay
 Cell wall protects and determines
shape.
 Contains peptidoglycan (carbohydrate)
 Example:
 E. coli= live in intestines of humans

7. Archaebacteria “ancient bacteria”
 Live in extreme environments
 Direct ancestors of eukaryotes
 Examples:
 Methanogens= oxygen free
environments thick mud and digestive
tracks.
 Halophites= Salty environments Utah’s
Great Salt Lake

8. Prokaryotes are Identified By
their…
 1. Shape
 2. Chemical Nature
 3. The way they move
 4. The way they obtain
energy.

9. Shapes of Bacteria
 Spherical (round / cocci)
 Streptococcus aureus
 Spiral (sprilla)
 Trepnema pallidum (syphilis)
 Rod-Shaped (bacillus)
 Escherichia coli

10. Shapes of Bacteria

11. Structure of Bacteria

12. Cell Walls of Bacteria
 Gram staining helps distinguish between the 2
different types of bacteria.
 Gram +
 Thicker peptidoglycan walls
 Keeps dark
stain
 Appears purple
 Gram –
 Thinner
cell wall
 Appears pink

13. Gram Staining- Use to diagnose
& treat disease
 Gram +  Gram –
Harmless Harmful
Important  Unaffected by
in
food and many
dairy antibiotics.
Can’t penetrate
industries cell wall
 Turns purple  Turns pink
 Ex)
 Ex) E. coli
Streptococcus
pneumonia

14. Movement
 1) Flagella- whip
like structures
 2) Lash, snake, or
Flagella Position
spiral
 3) Glide along
slime

15. Obtaining Energy
 Heterotrophs-
 Getenergy by consuming organic
molecules made by other organisms.
 Autotrophs-
 Make their own food from inorganic
molecules.

16. Autotrophs
 Photoautotrophs
Use sunlight to convert carbon
dioxide & water to carbon
compounds and oxygen.
Ex: Cyanobacteria
 Chemoautrotrophs
Use energy from chemical reactions
to make organic carbon molecules
Live in darkness; ocean bottoms.

17. Releasing Energy
 Obligate aerobes- require oxygen
TB Mycobacteruim tuberculosis
 Obligate anaerobes- NO oxygen
Clostridium botulinum (canned
food)
 Facultative anaerobes- do not require
oxygen but are not killed by it.
E. coli (large intestines and canned
food)

18. Growth & Reproduction
 Some bacteria can divide in ~20
min
 3 ways bacteria divide
 1) binary fission
 2) Conjugation
 3) Spore formation

19. Bacteria Reproduction
 Binary fission
 Asexual – clones
 Splitting in ½
 1st growth
 2nd DNA is copied
 3rd splits into 2
cells

20. Conjugation
 Sexual reproduction
 Hollow bridge forms between 2
bacteria cells
Exchange of DNA
Result: increase in genetic
variation

21. Spore Formation
 Formed in unfavorable
conditions
 Can keep for months or years
 Produces a thick internal wall
that encloses the DNA &
cytoplasm
 Dangerous

22. Limiting Factors in Bacteria
Reproduction (Growth)
 Nutrients
 temp (freeze/
pasteurization)
 Moisture
 pH
 Time
 Sanitizing

23. Importance of Bacteria
 1. Producers
 2. Decomposers
 3. Human uses

24. 1) Producers / Nitrogen Fixers
 Plants & animals depend on bacteria
for nitrogen
 Need N2 to make amino acids.
 N2 makes up ~ 80% of Earth’s atm
 Plants take N2 convert it to NH3
(ammonia) this process is known as
nitrogen fixation is done by
bacteria.

25. 2) Decomposers
 Bacteria recycle nutrients
 Trees die -> Bacteria break
down -> Nutrients are returned
to the soil -> Process repeats

26. 3) Human Uses
 Food- cheese, yogurt
 Beverages- wine, milk
 Industry- digest petroleum, clean
up oil spills
 Medical uses- synthesize drugs
 E. coli- makes vitamins the body
cannot make
 Etc.