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PART I Chapter 18 Archaebacteria & Eubacteria. Phylogeny. Characteristics. First living evidence on earth Unicellular Prokaryotes (No membrane-bound organelles) Cell wall with internal plasma membrane Found everywhere. Bacteria. Special Features. Pilus/pili - hairlike protrusion - PowerPoint PPT Presentation
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PART I Chapter 18
Archaebacteria & Eubacteria
Phylogeny
Characteristics• First living evidence on earth • Unicellular• Prokaryotes (No membrane-bound organelles)• Cell wall with internal plasma membrane• Found everywhere
Bacteria
Special Features
• Pilus/pili - hairlike protrusion– to stick to surfaces– a bridge for sexual reproduction
• Flagellum - long, whiplike protrusion, for moving
• Capsule - sticky layers around cell wall
• Toxin - a powerful poison
• Endospore – found in some bacteria– resists harsh environments
Flagella
Capsules
Endospores
Endospores
Classification:
• Shape– Cocci (Spheres), Bacilli (Rods), Spirilli (Spiral)
• Gram stain - Cell wall type– Thick = Purple Stain = “Gram Positive”– Thin = Pink Stain = “Gram Negative”
• Growth patterns– Diplo- pairs– Staphylo- clusters – Strepto- chains
Shapes
Gram Stain
Growth Patterns
Streptococci
Pneumonia
PART IIChapter 18
Archaebacteria & Eubacteria
Archaebacteria – ancient bacteria
Methanogens
Live in:Oxygen-free env.Produce methane
gas
Halophiles
Live in:Salt water
Acidophiles:
Live in:Hot, acidic
water
Eubacteria - “True” bacteria
• Live in more habitable environments
Heterotrophs
Photosynthetic
Autotrophs
Chemosynthetic
Autotrophs
Saprophytes (decomposers)
Need sunlight to make food
Need sulfur & nitrogen to make food
Parasites (cause disease)
Example: Cyanobacteria
Nitrogen fixation
(FIX the nitrogen)
Cyanobacteria - “blue-green bacteria”Algae + Bacteria
Sulfur Bacteria
Beneficial Bacteria• Nitrogen fixation
– Converts nitrogen into ammonia
– a form that plants can use
• Nodules – A symbiotic relationship
between bacteria and plants
(Beneficial Bacteria)
• Saprophytes (decomposers) – Breaks down dead organisms and
decaying matter– Returns nutrients to soil
(Beneficial Bacteria)
• Make food:– Cheese– Pickles– Yogurt– Vinegar– Sauerkraut
Cellular Respiration
Obligate Aerobes
Obligate Anaerobes
Need Oxygen Die from Oxygen
Pathogenic Bacteria – disease-causing bacteria
• Pathogen – an organism that causes disease
• Produce toxins
• Damage host’s tissues
• Enter through openings in body (via air, food, water)
Antibiotics:~ Destroys cell wall of bacteria~ Creates holes in the cell walls
• Sir Alexander Fleming1928 - discovered Penicillium notatum
Air-Born
Air-Born Bacteria
Reproduction
Asexual• Binary Fission
– Cell division
• Rapid - 20 min.
Sexual• Conjugation – exchange
genetic material• Pili/pilus - bridge
Binary Fission: Asexual Reproduction
Conjugation - Sexual Reproduction