Download The Prokaryotes Prokaryotes—characteristics Ecological Importance

The Prokaryotes
EUBACTERIA
(Bacteria)
ARCHAEBACTERIA
(Archaea)
EUKARYOTES
(Eukarya)
• Only two groups
• Archaebacteria and Eubacteria
• Arose before the eukaryotes
Prokaryotes—characteristics
• Single-celled
• Metabolically diverse
• No nuclear
membrane
• Single chromosome
• No organelles
• Very small
• Cell wall
• Flagella rotate like
propellers
• Pili extend from the
cell surface for
adhesion or motion
Bacteria—what do they look
like?
Ecological Importance of
Prokaryotes
• Decomposition
• Nitrogen fixation
• Mutualistic relationships
• Parasitic relationships
• Commercial uses
Treponema pallidum,
a spiral-shaped
bacteria which
causes Syphilis in
humans
Prokaryotic Fission
Rods, spheres, spirals, vibrio
Fig. 21-5, p.335
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Bacterial Diversity
• Photoautotrophic
– Aerobic (Cyanobacteria)
– Anaerobic (Green bacteria)
• Bacteria, often in combination with yeasts
and molds, are used in the preparation of
fermented foods such as:
– cheese, pickles, soy sauce, sauerkraut,
vinegar, wine, and yogurt.
• Chemoautotrophic
– Important in nitrogen cycle
• Chemoheterotrophic
– Largest group
• Some bacteria act as pathogens
– tetanus, typhoid fever, pneumonia, syphilis,
cholera, food-borne illness, leprosy, and
tuberculosis(TB).
– In plants, bacteria cause leaf spot, fireblight,
and wilts.
– The mode of infection includes contact, air,
food, water, and insect-borne microorganisms
Archaebacteria
• Bacteria are also important to numerous
industrial processes,
– wastewater treatment
– industrial production of antibiotics and other
chemicals.
EUBACTERIA
(Bacteria)
ARCHAEBACTERIA
(Archaea)
EUKARYOTES
(Eukarya)
Methanogens
Methanogens
Extreme halophiles
Extreme thermophiles
Fig. 21-11b, p.340
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Extreme Thermophiles
Extreme Halophiles
Fig. 21-12a, p.341
Fig. 21-12b, p.341
Where Do Viruses Fit?
• Not “alive”?
• Not a cell
• Nucleic acids in protein shell
• Do not grow, do not maintain
homeostasis, and do not
metabolize on their own
• Use host cell to replicate
• Lytic and Lysogenic life cycles
Early Stage of
Influenza Virus
Viruses
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Chicken pox
H1N1
Hepatitis
HIV - human immunodeficiency virus
Measles
Mononucleosis
Mumps
Respiratory Syndrome (SARS)
Smallpox
Why don’t antibiotics work for
colds and flu?
Why don’t they destroy your
body’s cells?
Hint: Antibiotics often work by
disrupting the bacteria cell wall.
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