1. BACTERIA
The Oldest Living Structures on
the Earth!
http://
www.ted.com/talks/lang/en/bonnie_bassler

2. Kingdom Archaebacteria
 Most inhabit extreme environments on the
earth. There are THREE main groupings.
– Methanogens
 Are anaerobic and live in swamps, marshes, the
guts of animals, and sewage treatment ponds
– Extreme Halophiles
 Live in high salt areas such as the Dead Sea and
the Great Salt Lake
– Extreme Thermophiles
 Live in hot springs with temperatures of 60oC to
80oC
 Cell walls do not contain peptidoglycan

3. Kingdom Eubacteria
 Prokaryotic
 Includes the spirochetes, gram-positive
bacteria and cyanobacteria
 Live just about anywhere
 Have a cell wall that contains
peptidoglycan (carbohydrate)

4. Kingdom Comparison
EUBACTERIA ARCHAEBACTERIA
Nuclear Absent Absent
Envelope
Membrane Absent Absent
Organelles
Peptoglycan Present Absent
Cell Wall
Ribosomes Present Present

5. Size Relationships
 10 Microns
 Virus (.05 – 1 micron)
 Bacteria (.05 – 1.5 microns)
 Red blood cell (5 microns)
 White blood cell (5-8
Microns)
 Sperm (60 microns)

6. Bacterial Shapes
 Bacillus bacteria are rod
shaped
 Cocci bacteria are round
 Spirillum are spiral shaped

8. Groupings of Bacteria
 Individual
 Diplo – in pairs
 Strepto – in chains
 Staphlo – clustered like grapes

9. Identification
 Gram Stain
– The gram stain differentiates bacteria on the
basis of structure and composition of the
layers of the cell wall.
– After staining:
 Gram positive bacteria appear purple
 Gram negative bacteria appear pink.
– Cell walls have a simpler structure than gram
negative cell walls

10. Gram Stain

11. General Structure
 Nearly all prokaryotes
have cell walls
 Bacteria have one
major chromosome
and rings of DNA
called plasmids
 Ribosomes are
present to help in
protein formation

12. General Structure
Ribosome
Peptidoglycan
Cell Cell
wall membrane  Many disease
causing bacteria
have a thick
outer slime
capsule for
protection
 Many bacteria
have small hair-
Flagellum DNA Pili like pili to attach
to other cells

13. Bacteria Cell Structure
 Single cell
 Nucleoid (plasmid)
– Area where single DNA strand is found
 Flagella
– For movement
 Capsule (Peptidoglycan)
– Coating on outside of cell wall

14. Bacteria Cell Structure
 Cell Wall
– Tough, rigid structure for support, shape and
protection
– Main function – prevent osmotic rupture
– Water always moving in cell, so if cell wall OK,
cell is OK
– Bacteria growing in Penicillin grow holes in
their cell walls, rupture, and die
 Cell membrane
 Ribosomes for making proteins

15. Bacteria Cell Structure
 Cells Alive: http://www.cellsalive.com/cells/bactcell.htm

16. Bacterial Reproduction
 Prokaryotes
– Reproduce asexually by binary fission (cell
splits apart)
– Continually making new DNA in good
conditions
– In bad conditions, form endospore
 Internal resting cell that surrounds the DNA, some
cytoplasm, and thick outer coat
 May live in for long time

17. Bacterial Reproduction
 Genetic Information Exchanged 3 Ways
– Transformation
 Genes taken up from the surrounding environment
– Conjugation
 Genes are transferred from cell to cell (sexually—
through a tube)
– Transduction
 Genes are transferred between prokaryotes by
viruses

18. Bacterial Population Growth
 Click on the icon above. Upon viewing the
dividing bacteria, take note of the FOUR
stages of the population growth curve

19. Aerobic vs. Anaerobic
 Aerobic  Anaerobic
– Obligate aerobes – Obligate anaerobes
 Must have oxygen  Must live where there is
present to live no oxygen
 Get energy from
fermentation
– Faculative anaerobes
 Live where there is
oxygen
 Live where there is no
oxygen

20. Bacterial Nutrition
 Autotrophs  Heterotrophs
– Make own food – Decomposers
– Smelly food caused by  Feed on dead plants
bacteria that are and animals
 Usually do not cause
making food from
disease
substances that have
 Ex: Nitrogen Cycle
sulfur or iron
– Parasites
 Live on or in living
organisms
 Can cause disease

21. Economic Importance of Bacteria
 Nitrogen Fixation
– All organisms need nitrogen to make proteins
– Bacteria convert nitrogen to a form organisms
can use
 Recycling of Nutrients
– Necessary to breakdown the organic matter in
dead organisms and wastes, returning
nutrients to the soil

22. Economic Importance of Bacteria
 Food
– Breakdown chemicals for their food by
fermentation
– Release other molecules we use because of
distinct flavors and aromas (cheese, yogurt,
sauerkraut)
 Medicines
– Produce antibiotics which kill other bacteria

23. Economic Importance of Bacteria
 Disease
– Only a few
– About half of all human diseases are caused
by bacteria

24. Food Bourne Bacteria
Can Harm You
 Botulism
 Salmonella
 Staphylococcus
 E. Coli

25. Staphylcoccus

26. Staphylcoccus aureus

27. E. Coli bacteria

28. What type of Bacteria is this?

29. Staphylcoccus - MRSA

30. Bacteria Colonies

31. This is what we are going to do.