Bacteria

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Bacteria

  1. 1. BacteriaStructure and Function 1 1
  2. 2. Prokaryotic &Eukaryotic Cells 2
  3. 3. Classification of Life 3 3
  4. 4. Three Domains of Life• Archaea – prokaryotes living in extreme habitats• Bacteria- Cyanobacteria and eubacteria• Eukarya – Protozoans, fungi, plants, & animals 4
  5. 5. Kingdoms of BacteriaArchaebacteria: Found in harsh environments Undersea volcanic vents, acidic hot springs, salty water 5
  6. 6. Archaebacteria 6
  7. 7. Kingdoms of Bacteria Eubacteria:  Called the true bacteria  Most bacteria are in this group  Include photosynthetic Cyanobacteria 7
  8. 8. Eubacteria 8
  9. 9. Characteristics of Bacteria 9 9
  10. 10. Bacterial Structure• Microscopic prokaryotes• No nucleus or membrane- bound organelles• Contain ribosomes• Single, circular chromosome in nucleoid region 10
  11. 11. Bacterial Cell 11
  12. 12. Protection• Cell Wall made of Peptidoglycan• May have a sticky coating called the Capsule for attachment to host or other bacteria 12
  13. 13. Sticky Bacterial Capsule 13
  14. 14. Bacterial Structure PLASMIDS• Have small rings of DNA called Plasmids• Unicellular• Small in size (0.5 to 2μm ) [micometer] 14
  15. 15. 15
  16. 16. Bacterial Structure• Infoldings of cell membrane carry on photosynthesis & cellular respiration• Infoldings called Mesosomes 16
  17. 17. Mesosomes MESOSOME 17
  18. 18. Bacterial Structure• Most grow best at pH of 6.5 to 7.0• Many act as decomposers recycling nutrients• Some cause disease 18
  19. 19. Staphylococcus Bacterial 19
  20. 20. Beneficial Uses of Bacteria 20
  21. 21. Useful Bacteria• Some bacteria can degrade oil• Used to clean up oil spills 21
  22. 22. Environmental Clean-up• Some bacteria eat oil and turn it into environmentally friendly chemicals. These bacteria are dumped into waters contaminated by oil spills. 22
  23. 23. Environmental Recycling • Bacteria are decomposers: they break down dead organisms into smaller chemicals which then go back into the soil. 23
  24. 24. Digestion• Many bacteria, such as human E. coli, live a warm and cozy life in your intestines. They help digest your food and make vitamins, such as Vitamin K (which is necessary for blood clotting). 24
  25. 25. Digestive Health• Beneficial bacteria, such as Lactobacillus, keep the “bad” bacteria in check, by competing with them for nutrients. 25
  26. 26. Medicines• The pharmaceutical industry uses some forms of bacteria to make vitamins and antibiotics.• Other bacteria can be used to produce insulin, which can be collected and given to people with diabetes. 26
  27. 27. Useful Bacteria• Other uses for bacteria include making yogurt, cheese, and buttermilk. 27
  28. 28. Fuel Production• Archaebacteria produce methane gas, which makes up 20% of the world’s natural gas used for fuel. 28
  29. 29. Flagella• Bacteria that are motile have appendages called flagella• Attached by Basal Body• A bacteria can have one or many flagella 29
  30. 30. Monotrichous LophotrichousAmphitrichous Peritrichous 30
  31. 31. Question:What is this type of bacteria ? 31
  32. 32. Pili• Short protein appendages• Smaller than flagella• Adhere bacteria to surfaces• Used in conjugation for Exchange of genetic information• Aid Flotation by increasing buoyancy 32
  33. 33. Pili in Conjugation 33
  34. 34. Bacterial Shapes 34 34
  35. 35. Shapes Are Used to Classify• Bacillus: Rod shaped• Coccus: Spherical (round)• Vibrio: Comma shaped with flagella• Spirillum: Spiral shape• Spirochete: wormlike spiral shape 35
  36. 36. 36
  37. 37. Grouping of Bacteria • Diplo- Groups of two • Strepto- chains • Staphylo- Grapelike clusters 37
  38. 38. 38
  39. 39. 39
  40. 40. Diplococcus 40
  41. 41. Streptococcus Causes Strep Throat 41
  42. 42. Staphylococcus 42
  43. 43. Bacillus - E. coli 43
  44. 44. BacterialKingdoms 44 44
  45. 45. Archaebacteria• Lack peptidoglycan in cell walls• Have different lipids in their cell membrane• Different types of ribosomes• Very different gene sequences 45
  46. 46. Archaebacteria• Archaebacteria can live in extremely harsh environments• They do not require oxygen and can live in extremely salty environments as well as extremely hot environments• Called the Ancient bacteria 46
  47. 47. Archaebacteria• Subdivided into 3 groups:MethanogensThermoacidophilesExtreme Halophiles 47
  48. 48. Methanogens• Live in anaerobic environments (no oxygen)• Get energy by changing H2 & CO2 into methane gas• Found in swamps, sewage treatment plants, digestive tracts of animals 48
  49. 49. Methanogens• Break down cellulose in a cow’s stomach• Produce marsh (methane) gas 49
  50. 50. Extreme Halophiles• Live in very salty water• Use salt to generate ATP (energy)• Dead Sea, Great Salt Lake inhabitants 50
  51. 51. Thermoacidophiles or Thermophiles• Live in extremely hot environments• Found in volcanic vents, hot springs, cracks on ocean floor that leak acid 51
  52. 52. KingdomEubacteria True Bacteria 52 52
  53. 53. Characteristics• 3 basic shapes (coccus, bacillus, spirilla)• Most are heterotrophic (can’t make their own food)• May be aerobic or anaerobic• Identified by Gram staining 53
  54. 54. Gram Staining• Developed in 1884 by Hans Gram• Bacteria treated with purple Crystal Violet & red Safranin stains• Cell walls either stain purple or reddish pink 54
  55. 55. Gram Positive• Have thick layer of peptidoglycan (protein-sugar complex)• Single lipid layer• Stain purple• Can be treated with antibiotics 55
  56. 56. Gram Positive BacteriaLactobacilli (makes yogurt & buttermilk)Actinomycetes (make antibiotics)Clostridium (lockjaw bacteria)Streptococcus (strep throat)Staphylococcus (staph infections) 56
  57. 57. Gram Negative Bacteria• Thin layer of peptidoglycan in cell wall• Extra thick layer of lipids• Stain pink or reddish• Hard to treat with antibiotics• Some photosynthetic but make sulfur not oxygen• Some fix nitrogen for plants 57
  58. 58. Gram Negative• Rhizobacteria grow in root nodules of legumes (soybeans, peanuts)• Fix N2 from air into usable ammonia 58
  59. 59. Gram Negative• Rickettsiae are parasitic bacteria carried by ticks• Cause Lyme disease & Rocky Mountain Spotted Fever 59
  60. 60. Cyanobacteria• Gram negative• Photosynthetic• Called blue-green bacteria• Contain phycocyanin (red- blue) pigments & chlorophyll 60
  61. 61. Cyanobacteria• May be red, yellow, brown, black, or blue-green• May grow in chains (Oscillatoria)• Have Heterocysts to help fix N2• First to re-enter devastated areas• Some cause Eutrophication (use up O2 when die & decompose in water) 61
  62. 62. Cyanobacteria 62
  63. 63. Spirochetes• Gram positive• Flagella at each end• Move in corkscrew motion• Some aerobic; others anaerobic• May be free living, parasitic, or symbiotic 63
  64. 64. Enteric Bacteria• Gram negative• Can live in aerobic & anaerobic habitats• Includes E. coli in intestines• Salmonella – causes food poisoning 64
  65. 65. Chemoautotrophs• Gram negative• Obtain energy from minerals like iron• Found in freshwater ponds 65
  66. 66. Nutrition,Respiration, and Reproduction 66 66
  67. 67. 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 67
  68. 68. Methods of Respiration • Obligate Aerobes – require O2 (tuberculosis bacteria) • Obligate Anaerobes – die if O2 is present (tetanus) • Facultative Anaerobes – don’t need O2, but aren’t killed by it (E. coli) 68
  69. 69. Bacterial Respiration• Anaerobes carry on fermentation• Aerobes carry on cellular respiration 69
  70. 70. Reproduction• Bacteria reproduce asexually by binary fission• Single chromosome replicates & then cell divides• Rapid• All new cells identical (clones) 70
  71. 71. Cellular organism copies it’s genetic information then splits into two identical daughter cells 71
  72. 72. Binary Fission E. coli 72
  73. 73. Reproduction• Bacteria reproduce sexually by Conjugation• Form a tube between 2 bacteria to exchange genetic material• Held together by pili• New cells NOT identical 73
  74. 74. Conjugation 74
  75. 75. Spore Formation• Form endospore whenever when habitat conditions become harsh (little food)• Able to survive for long periods of time as endosperm• Difficult to destroy (heat resistant) 75
  76. 76. Transduction & Transformation• Genetically change bacteria• May become antibiotic resistant• Transformed bacteria pick up pieces of DNA from dead bacterial cells• Transduction – viruses carry foreign DNA to bacteria; used to make insulin 76
  77. 77. Pathenogenic Bacteria 77 77
  78. 78. Pathogens• Called germs or microbes• Cause disease• May produce poisons or toxins• Endotoxins released after bacteria die (E. coli)• Exotoxins released by Gram + bacteria (C. tetani) 78

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