Transcript Diversity of Prokaryotes

Bacteria
Section 18.2
Diversity of Prokaryotes
• Belong to the kingdoms Archaebacteria
and Eubacteria
• Because they are so different, many
scientists propose that archaebacteria and
eubacteria arose from a common ancestor
several billion years ago.
Archaebacteria: The extremists
• There are three types of archaebacteria
that live mainly in extreme habitats where
there is usually no free oxygen available.
– Methane gas producers
• Lake sediments
• Cow intestines
• Sewage treatment plants
Archaebacteria: The extremists
– water with high concentrations of salt.
Dead Sea
Archaebacteria: The extremists
– hot, acidic
waters of sulfur
springs.
– These bacteria
are
chemautotrophic
(make energy
from chemicals)
Eubacteria: true bacteria
• Some are autotrophic
– Photosynthetic
• Cyanobacteria
– Some are
chemautotrophic
Eubacteria: true bacteria
• Some are heterotrophic = “eaters”
– Decomposers: break down dead plants or
animals
– Symbiotic: have close association with
another organism (parasitic or mutualistic)
Bacterial Cells
• Smallest single-celled organisms (2μm)
• Prokaryotic (lack a nucleus)
• Have a cell wall
– Made of peptidoglycan (unique)
– Cytoplasm is hypertonic, protects cell from
exploding
– Antibiotics may disrupt cell wall
Bacteria on a
pin
Bacterial Cells
• May be surrounded by a capsule
– Sticky
– Protects
• May have flagella
• May form endospore under harsh
conditions
– Withstands boiling, drying up
– Cell emerges when conditions improve
Anthrax
endospore
Bacterial Cells
• Different shapes
– Coccoid = spherical
– Baccilus = rod-shaped
– Spirillus = spiral shaped
Bacterial Reproduction
• Binary fission (bacterial cell division)
Nitrogen Fixation
• Ability to convert nitrogen gas to ammonia
that a plant can use
• Legumes (clover, beans, alfalfa) have
these bacteria near roots
– Rotated crop
Bacterial Importance
• Major Decomposers
• Can cause disease
• Can cure disease (many antibiotics come
from bacteria)
• Can spoil food
• Can make food
– Yogurt, cheese, vinegar, sauerkraut
Bacteria cause disease
Diseases Caused by Bacteria
Disease
Transmission Symptoms
Fever, sore throat,
Inhale or
Strep throat
ingest through swollen neck glands
(Streptococcus)
mouth
Inhale
Fatigue, fever, night
Tuberculosis
sweats, cough, weight
loss, chest pain
Puncture
Stiff jaw, muscle
Tetanus
wound
spasms, paralysis
Rash at site of bite,
Lyme disease
Bite of
infected tick chills, body aches,
joint swelling
Bacteria
Destruction of tooth
Dental
cavities (caries) in mouth
enamel, toothache
Sore throat, fever,
Inhale or
Diptheria
close contact heart or breathing
failure
Treatment
Antibiotic
Antibiotic
Open and clean wound,
antibiotic; give antitoxin
Antibiotic
Remove and fill the
destroyed area of tooth
Vaccination to
prevent, antibiotics