part i chapter 18 archaebacteria & eubacteria. phylogeny
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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
Bacteria Structures• Cell wall – provides support and protection to
the cell
• Plasma membrane – flexible, selectively permeable boundary that controls what enters and leaves the cell
• Cytoplasm – semi-fluid material inside the cell’s plasma membrane
• Ribosome – organelle that helps to manufacture proteins
• DNA - stores and communicates genetic information for the cell
Bacteria Structures
• 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:Three Basic Shapes
Cocci -Spheres
Bacilli -Rods
Spirilli -Spiral
Classification:
• Gram stain – Cell wall type
• Thick – Purple Stain = “Gram Positive”
• Thin - Pink Stain = “Gram Negative”
Growth Patterns
Diplo- pairsStaphylo- clusters Strepto- chains
Streptococci
Pneumonia
PART IIChapter 18
Archaebacteria & Eubacteria
Archaebacteria – ancient bacteria
Methanogens
Live in:Oxygen-free environment
Produce methane gas
Halophiles
Live in:Salt water
Acidophiles:
Live in:Hot, acidic
water
Eubacteria - “True” bacteria
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)
Live in more habitable environments
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
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