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Bacteria

Bacteria. Structure and Function. Prokaryotic & Eukaryotic Cells. Earliest Prokaryotes. Most numerous organisms on Earth Include all bacteria Earliest fossils date 2.5 billion years old. Classification of Life. Three Domains of Life. Archaea – prokaryotes living in extreme habitats

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Bacteria

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  1. Bacteria Structure and Function

  2. Prokaryotic & Eukaryotic Cells

  3. Earliest Prokaryotes • Most numerousorganisms on Earth • Include allbacteria • Earliest fossils date2.5 billion years old

  4. Classification of Life

  5. Three Domains of Life • Archaea – prokaryotes living in extreme habitats • Bacteria- Cyanobacteria and eubacteria • Eukarya – Protozoans, fungi, plants, & animals

  6. Kingdoms of Bacteria Archaebacteria: • Found in harsh environments • Undersea volcanic vents, acidic hot springs, salty water

  7. Archaebacteria

  8. Kingdoms of Bacteria Eubacteria: • Called the true bacteria • Most bacteria are in this group • Include photosynthetic Cyanobacteria

  9. Eubacteria

  10. Characteristics of Bacteria

  11. Bacterial Structure • Microscopic prokaryotes • No nucleus or membrane-bound organelles • Contain ribosomes • Single, circular chromosome in nucleoid region

  12. Bacterial Cell

  13. Protection • Cell Wall made of Peptidoglycan • May have a sticky coating called the Capsule for attachment to host or other bacteria

  14. Sticky Bacterial Capsule

  15. Bacterial Structure • Have small rings of DNA called Plasmids • Unicellular • Small in size (0.5 to 2μm) PLASMIDS

  16. Bacterial Structure • Infoldingsof cell membrane carry on photosynthesis & cellular respiration

  17. Bacterial Structure • Most grow best at pH of 6.5 to 7.0 • Many act as decomposers recycling nutrients • Some cause disease

  18. Staphylococcus Bacterial

  19. Useful Bacteria • Some bacteria can degrade oil • Used to clean up oil spills

  20. Useful Bacteria • Other uses for bacteria include making yogurt, cheese, and buttermilk.

  21. Pili • Short protein appendages • Smaller than flagella • Adhere bacteria to surfaces • Used in conjugation for Exchange of genetic information • Aid Flotation by increasing buoyancy

  22. Pili in Conjugation

  23. Bacterial Shapes

  24. Shapes Are Used to Classify • Bacillus: Rod shaped • Coccus: Spherical (round) • Vibrio: Comma shaped with flagella • Spirillum: Spiral shape • Spirochete: wormlike spiral shape

  25. Grouping of Bacteria • Diplo- Groups of two • Strepto- chains • Staphylo- Grapelike clusters

  26. Diplococcus

  27. Streptococcus Causes Strep Throat

  28. Staphylococcus

  29. Bacillus - E. coli

  30. Streptobacilli

  31. Spirillum

  32. Spirochetes

  33. Bacterial Kingdoms

  34. Archaebacteria • Lack peptidoglycan in cell walls • Have different lipids in their cell membrane • Different types of ribosomes • Very different gene sequences

  35. 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

  36. Archaebacteria • Subdivided into 3 groups: • Methanogens • Thermoacidophiles • Extreme Halophiles

  37. 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

  38. Methanogens • Break down cellulose in a cow’s stomach • Produce marsh (methane) gas

  39. Extreme Halophiles • Live in very salty water • Use salt to generate ATP (energy) • Dead Sea, Great Salt Lake inhabitants

  40. Thermoacidophiles or Thermophiles • Live in extremely hot environments • Found in volcanic vents, hot springs, cracks on ocean floor that leak acid

  41. Kingdom Eubacteria True Bacteria

  42. 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

  43. 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

  44. Gram Positive • Have thick layer of peptidoglycan (protein-sugar complex) • Single lipid layer • Stain purple • Can be treated with antibiotics

  45. 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

  46. Gram Negative • Rhizobacteria grow in root nodules of legumes (soybeans, peanuts) • Fix N2 from air into usable ammonia

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