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Bacteria

Bacteria. Chapter 19-1. Microscopic organisms. Viruses = not living, but studied as micro- Bacteria = divided into 2 kingdoms; most are helpful, harmful tracked by CDC & WHO Protists = most diverse; show fungal, plant or animal characteristics

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Bacteria

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  1. Bacteria Chapter 19-1

  2. Microscopic organisms • Viruses = not living, but studied as micro- • Bacteria = divided into 2 kingdoms; most are helpful, harmful tracked by CDC & WHO • Protists = most diverse; show fungal, plant or animal characteristics • Fungus = decomposers; most are helpful, some are disease-causing

  3. Prokaryote characteristics • Single-cell organisms • Anucleated (no nucleus) • Small (1-5 m) • Lacks organelles • Variety of shapes • Variety of growth patterns • Two kingdoms: Eubacteria and Archaebacteria

  4. Bacterial characteristics: • Prokaryotic (no nuclear membrane) • Ribosomes only • Pili = for attachment • Capsule = outermost layer for extra protection • Unicellular (some colonial) • Varied metabolism & nutritional types • Often flagellated • May contain endospores… to survive harsh conditions • Binary fission to reproduce

  5. Archaebacteria • Extremophiles: organisms that prefer extreme environments • Ex: salt marshes, deep sea ocean vents, swamps, etc. aerobic halophil

  6. Archaebacteria • Lack the peptidoglycan of Eubacteria • Have different membrane lipids • DNA sequences are more like those of eukaryotes

  7. Chemosynthetic bacteria in deep sea vents Photosynthetic Cyanobacteria in fresh-water ponds or streams

  8. Eubacteria cell structure Cell wall Cell membrane Ribosome Peptidoglycan Pili DNA Flagella

  9. See page 465

  10. Practice

  11. Bacterial shapes • Bacillus = rod-shaped (ex: Lactobacillus) • Coccus = sphere (ex: Streptococcus) • Spirillum = coiled (ex: Spirochete) • Strepto- (chains) • Staphylo- (clusters) (like grapes) • Diplo- (pairs)

  12. Bacterial morphology CoccusBacillus Spirillum

  13. Blue = causes Lyme disease Black = causes syphilis

  14. A Bacilli with and without flagella B Streptococci C Staphylococci D Diplococci E Spirochete F Club rod G Filamentous H Streptobacilli

  15. Movement • Depending upon how the cells is flagellated, movements such as gliding or tumbling may occur. flagellated E. coli

  16. Gram stain • a technique that determines the differences in the composition of bacterial cell walls (thick or thin) which helps to determine which antibiotics to use. Gram-positive bacteria thick peptidoglycan cell walls. Gram-negative bacteria thinner cell walls with a outer lipid layer.

  17. Gram negative Gram positive

  18. How bacteria obtain nutrition • Heterotrophs: consume carbon matter to make ATP • Chemoheterotroph: consumes only • Photoheterotroph: consumes and photosynthesizes Gram-negative, facultative anaerobic

  19. How bacteria obtain nutrition • Autotrophs: produces carbon matter to make ATP • Photoautotroph: produces with light energy (photosynthesis) • Chemoautotroph: produces carbon matter without light source Chemoautotroph: Purple sulfur bacteria

  20. Nutritional diversity(Recap) • Autotrophs: (producers) • Photosynthetic = Cyanobacteria • Chemosynthetic= bacteria in deep ocean vents use sulfur instead of light for energy • Heterotrophs: (consumers) • Saprobes = decomposers feed on dead organic matter (nitrogen-fixing bacteria) • Parasitic = feed on living host (pathogenic)

  21. Oxygen requirements • Obligate aerobe: requires constant oxygen supply in environment • Facultative aerobes: prefers oxygen, but not necessary • Facultative anaerobe: can survive with or without oxygen • Obligate anaerobe: requires constant lack of oxygen in environment

  22. Binary fission • asexual method of reproduction • parent cell splits into two daughter cells • Daughter cells are identical to parent cell

  23. Binary fission • Cell Replication • (cloning) for prokaryotic cell • Much simpler than mitosis (like cytokinesis without the 4 other stages)

  24. Conjugation • Genetic material exchange • Increases genetic variation within bacterial population

  25. Spore formation • In unfavorable growth conditions, structures (endospores) form to protect the bacterium. • Thick wall encloses the DNA and a small amount of cytoplasm. • The rest of the cell dies off. • The spore can survive in tough conditions for years. • Ex: Bacillus anthracis (anthrax) causes black necrotic lesions, sudden massive chest oedema followed by cardiovascular shock then death

  26. Endospore formation

  27. Methods of Microbe Transmission 3) Fomites: (inanimate objects) 1) Direct Contact: 2) Air:

  28. Early microbiologists • Louis Pasteur • Concluded that microorganisms cannot spontaneously generate • Showed world how heat kills microorganisms (pasteurization)

  29. Microorganisms & You • Food for heterotrophs typically are carbon-based macromolecules: • Carbohydrates, lipids, & proteins • Bacteria & fungus are responsible for food spoilage because many are saprobes

  30. Helpful bacteria • Decomposers • Nitrogen fixers: Rhizobium • Symbiosis with humans in large intestines • Food production Rhizobium

  31. Food & Microorganisms:Making cheese • Bacteria placed in an anaerobic environment, and the milk breaks down to form cheese • Milk (sugar source) + little oxygen → lactic acid + protein solids + curds “Little Miss Muffet, sat on her tuffet, eating her… cottage cheese”

  32. Yogurt: • Yogurt is produced by a mixed culture of 2 types of bacteria. Imbedded in particles of the protein casein, you will see chains of cocci or diplococci (Streptococcus thermophilus) and big rod-shaped bacilli (either Lactobacillus acidophilus or L. bulgaricus). Buttermilk: • Buttermilk is the fermentation of milk by a culture of lactctic-acid producing Streptococcus lactis plus Leuconostoc citrovorum which converts lactic acid to aldehydes and ketones which gives buttermilk its flavor and aroma.

  33. Making cured meats • Some bacteria are able to ferment meat products • The final products are sausages, bologna, salami, country cured hams, etc

  34. Making pickled vegetables • Sauerkraut is a product of lactic acid fermentation of Lactobacillus genus bacteria. • Bacteria ferments the cabbage, but salt is added to prevent other bacteria from spoiling the product.

  35. Bacon and Pancetta Elenski but Sausage Salami Pepperoni Chorizo Linguiça Fish Anchovy Salt cod Lox (salmon) Pickled herring Cured vegetable products: Tofu Sauerkraut Kimchi Pickled cucumbers Olive (fruit) Some cured food products • Cured animal products: • Beef • Corned beef • Bresaola • Tapa • Pork • Ham • Prosciutto • Jambon de Bayonne • Jamón serrano • Jinhua ham • Coppa • Lomo • Capicola • Lardon

  36. Nitrogen cycle includes nitrogen fixation

  37. How else are bacteria helpful? • Nitrogen-fixation • decomposing bacteria convert atmospheric N2 for use by autotrophs

  38. Symbiotic bacteria allow a host to live a different lifestyle than would normally be possible

  39. Cyanobacteria (& unicellular algae) produce most of the world’s oxygen by photosynthesis

  40. Microorganisms & your health Antibiotics that kill pathogenic microorganisms are made from microorganisms

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