Chapter 18.1
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•
Three Domains of
Life
Bacteria -
Cyanobacteria and eubacteria
• Archaea – prokaryotes living in extreme habitats
• Eukarya – Protozoans, fungi, plants, & animals
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Domain Bacteria
Kingdom Eubacteria
Found just about everywhere
Strong cell walls w/ peptidoglycan
Some have a secondary cell wall

Eubacteria
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Domain Archaea
Kingdom Archaebacteria
• Live in extreme and hostile environments
• Has ribosomal proteins similar to eukaryotic cells
• Cell walls lack peptidoglycans

Archaebacteria
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Methanogens
• Break down cellulose in a cow’s stomach
• Produce marsh
(methane) gas
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Extreme Halophiles
• Live in very salty water
• Use salt to generate
ATP (energy)
• Dead Sea,
Great Salt
Lake inhabitants
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Thermoacidophiles or
Thermophiles
• Live in extremely hot environments
• Found in volcanic vents, hot springs, cracks on ocean floor that leak acid
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Clicker Question!
Have a membrane bound nucleus and organelles:
A: Prokaryotes
B: Eukaryotes
C: Nokaryotes

Eubacteria vs Archaebacteria

Prokaryotic &
Eukaryotic Cells
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Earliest
Prokaryotes
• Most numerous organisms on
Earth
• Include all bacteria
• Earliest fossils date 2.5 billion years old
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What domain can be found in harsh environments like: Undersea volcanic vents, acidic hot springs, salty water?
A: Bacteria
B: Archaea
C: Eukarea
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Clicker Question!
Some eubacteria gain energy from the sun (cyanobacteria), but the rest have to gain energy by consuming other organisms. These are called:
A. Homotrophs
B. Heteroeaters
C. Heterotrophs
D. Homoconsumers

Bacterial Structure
• Microscopic
• Do not have a nucleus or membrane-bound organelles
PLASMIDS
• Have ribosomes
• Single, circular chromosome
• Have plasmids
• Unicellular
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Bacterial Cell
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Sticky Bacterial Capsule
Prevents drying out, allows it to attach to other surfaces, prevents it from being engulfed, & shelters it from antibiotics
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Pili in Conjugation
Hairlike structures that help them attach to surfaces and allow for transfer of genetic material between two bacteria
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Flagella
• Bacteria that are motile have appendages called flagella
• A bacteria can have one or many flagella
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Monotrichous
Amphitrichous
Lophotrichous
Peritrichous
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Clicker Question!
What structure does this bacterium use for motility?
A: Flagella
B: Cilia
C: Pili
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Shapes Used to
Classify
• Bacillus:
• Coccus:
• Spirillum:
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Grouping of Bacteria
• Diplo-
• Strepto-
• Staphylo-
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Clicker Question!
What shape and grouping describes the bacteria pointed out below?
A: Staphalacoccus
B: Streptobacillus
C: Diplococcus
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Staphylococcus
Bacterial
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Streptococcus Causes
Strep Throat
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Bacillus - E. coli
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Streptobacilli
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Spirillum
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Leptospira
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Clicker Question!
1. _________
2. _________
3. _________
4. _________
5. _________
A. Staphylococcus
B. Coccus
C. Spirillum
D. Bacillus
E. Streptococcus
F. Diplococcus
6. _________
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Gram Staining
• Developed in 1884 by
Hans Gram
• Bacteria treated with purple Crystal Violet & red
Safranin stains
• Cell walls either stain purple or pink
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Gram Positive
• Have a thick layer of peptidoglycan
• Stain purple
• Can be treated with antibiotics
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Gram Negative
Bacteria
• Thin layer of peptidoglycan in cell wall
• Outer layer of lipids
• Stain pink
• Hard to treat with antibiotics
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Gram Negative
• Rickettsiae are bacteria carried by ticks
• Cause Lyme disease & Rocky
Mountain
Spotted Fever
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Clicker Question!
Which type of bacteria is susceptible to antibiotics?
A: Gram Positive (Dark Purple)
B: Gram Negative (Light Pink)

2 kinds of reproduction:
• Binary fission
• Conjugation

Cellular organism copies it’s genetic information then splits into two identical daughter cells
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Binary Fission E. coli
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Clicker Question!
What kind of reproduction is depicted in the photo below?
A: Asexual
B: Conjugation
C: Binary fission
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Bacterial Respiration
• Anaerobes
• Aerobes
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Modes of Nutrition
• Saprobes – feed on dead organic matter
• Parasites – feed on a host cell
• Photoautotroph – use sunlight to make food
• Chemoautotroph – oxidize inorganic matter such as iron or sulfur to make food
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Bacteria and Survival

Bacterial Survival:
Mutations
• Reproduce quickly
• Low rate to fix mistakes in DNA
• Leads to increase in genetic diversity
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Bacterial Survival:
Endospores

Ecology of Bacteria

All living things need Nitrogen
Bacteria fix nitrogen to make it usable!
Bacteria decompose and recycle nutrients!

Normal Flora
•Harmless
•Live on, in, and around you
•E. coli helps make
Vitamin K used to help clot blood

Useful Bacteria
• Some bacteria can degrade oil
• Used to clean up oil spills
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Bacteria make food
• Yogurt
• Cheese
• Buttermilk
• Pickles
• Chocolate
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Bacteria make Medicine
• Vitamins
• Antibiotics:
–Streptomycin
–Bacitracin
–Tetracycline
–Vancomycin

Pathogens
STD: Syphilis, gonorrhea, Chlamydia
Respiratory: Strep throat, pneumonia, whooping cough, tuberculosis, anthrax
Skin: Acne, boils
Digestive: Gastroenteritis, food poisoning, cholera
Nervous: Botulism, tetanus, bacterial meningitis
Other: Lyme disease, typhoid fever
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