Transcript bacteria
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 II Chapter 18 Archaebacteria & Eubacteria Archaebacteria – ancient bacteria Methanogens Halophiles Acidophiles: Live in: Live in: Salt water Live in: Hot, acidic water Oxygen-free env. Produce methane gas Eubacteria - “True” bacteria • Live in more habitable environments Heterotrophs Saprophytes (decomposers) Photosynthetic Autotrophs Need sunlight to make food Parasites (cause Example: disease) Cyanobacteria Chemosynthetic Autotrophs Need sulfur & nitrogen to make food 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 Fleming 1928 - 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