1. An introduction to bacteria
They Are Everywhere
An introduction to bacteria

2. Prokaryotes
Prokaryote: Single-celled organism that lacks a true nucleus (also called bacteria)
DNA is not surrounded by a nuclear membrane, have no membrane bound organelles.
Cover almost every
cm2 of earth!

3. Size Matters Prokaryotes = 1-5 micrometers
Eukaryotes = micrometers
Vs.
Prokaryotic cells are much
smaller than eukaryotic
cells.

4. One to Two *Until recently all prokaryotes were one kingdom, Monera
Monera is now split into 2 kingdoms:
Eubacteria, Archaebacteria
Now three domains
Eubacteria/Bacteria
Archaea
Eukaryota/Eukarya

5. A hot springs in Yellowstone National park!
Archaebacteria!
A hot springs in Yellowstone National park!

6. Archaea
Lack peptidoglycan walls and have different membrane lipids than Eubacteria
DNA sequences are closer to Eukaryotes than Bacteria

7. Extremophiles – ‘phileo’ in Greek means love
Live in extreme environments!

8. Halophilic: salt loving

9. Thermophilic: heat loving

10. Methanogens – produce methane gas
Live in the gut of mammals,
sewage disposal
plants and swamps

11. Eubacteria Largest of prokaryote groups
*Have cell walls that contain peptidoglycan (carbohydrate)
Find everywhere on earth.

12. Ribosome
Flagella
Pili
Cell wall
Cell membrane
DNA
Plasmid
Cytoplasm

13. plays role during conjugation
Capsule – Protects against drying out, chemicals and host’s white blood cells.
Plasmid – piece of DNA ,
plays role during conjugation
Pili -
Help with
conjugation –
transferring
of genetic
material p.558,
Stick
to host’s cells
Flagella:
Movement
Ribosomes- Making
proteins
Cell wall - Protects, gives
cell shape
Eubacteria–has peptidoglycan
Cytoplasm -
Contains DNA, Proteins and plasmid
DNA - Carries the
genetic material
Cell membrane –
Regulates the movement of materials in and out of the cell

14. Shapes Three Shapes Bacili (rod-shaped) 3) Spirilla
(spiral or corkscrew)
2) Cocci
(spherical)

15. “Strep” throat

16. Form clumps like grapes
Shapes S S S
Streptococci
Streptobacilla
Streptospirilla
Form chains S S
Staphylococci
Staphylobacilla
Staphylospirilla
Form clumps like grapes

18. Cell Walls Two Types: Gram-Positive Gram-Negative
Thick peptidoglycan walls
Turn dark purple when stained
Gram-Negative
Much thinner walls inside an outer lipid layer
Appear pink or light red

19. Energy

20. Heterotrophs Parasitic – Cause diseases (pathogens)
Saprophytic – Feed on dead tissues - Decomposers

21. Autotrophs Photoautotrophs: Chemoautotrophs:
Use light energy to convert CO2 and H2O to food (like plants)
Ex: cyanobacteria
Chemoautotrophs:
Use chemical energy to convert CO2 and H2O to food

22. Releasing Energy Obligate Aerobes: Obligate Anaerobes:
Require constant supply of oxygen
Obligate Anaerobes:
Do not require oxygen It kills them
Facultative Anaerobes:
Do not require oxygen, but can live with it
Ex: E. coli

23. *Growth and Reproduction
Some bacteria can divide every 20 minutes
If there was unlimited resources 1 bacteria could grow into a mass 4000 times the mass of earth in just 48 hours!!!

24. Reproduction
Binary fission

25. 1) Binary Fission Binary Fission:
Asexual reproduction where organism replicates DNA and divides in half
Produces two identical daughter cells

26. 2) Conjugation Conjugation: (“Sexual” reproduction)
A type of sexual reproduction where organism exchange genetic information

27. 3. Forming Endospores Help survive unfavorable conditions.
Anthrax spores

28. Some are BAD and make us ill

29. Streptococcus
Strep throat
Pneumonia

30. Affects nervous system
Tetanus (lock jaw)
Affects nervous system
E. coli
Some in our intestines … others are pathogens that can cause kidney failure

31. Can be bad … but can be good
Bacteria
Can be bad … but can be good
intestines
Feel better with??
decomposers
antibiotics

32. Decomposers
Break down things into simpler materials and release into the soil
*Help breakdown sewage treatment water

33. Nitrogen Fixers
Converting nitrogen gas into a form plants can use (nitrates – NO3)
Allows nitrogen to cycle through biosphere
For example Rhizobium living
in the roots of legumes
Such as soybean plants.

34. Other Uses E. coli in our intestines Oil digestion/
Make vitamins that we cannot make
Oil digestion/
Clean up of pollutants
(Bioremediation)

35. Bacteria Are living: Made up of cells Have DNA Grow and develop
Use energy
Homeostasis
Reproduction
Show organization – Flagella, pili, plasmid.
Adapt/Evolve – Antibiotic resistance
Respond to stimuli - Endospores