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Bacteria

Bacteria. Structure and Function. Prokaryote & Eukaryote Evolution. Cellular Evolution. Current evidence indicates that eukaryotes evolved from prokaryotes between 1 and 1.5 billion years ago Two theories: 1. Infolding theory 2. Endosymbiotic theory. Infolding Theory.

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Bacteria

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  1. Bacteria Structure and Function

  2. Prokaryote & Eukaryote Evolution

  3. Cellular Evolution • Current evidence indicates that eukaryotes evolved from prokaryotes between 1 and 1.5 billion years ago • Two theories: 1. Infolding theory 2. Endosymbiotic theory

  4. Infolding Theory • The infolding of the prokaryotic plasma membrane gave rise to eukaryotic organelles. infolding organelle

  5. Endosymbiotic Theory • Endosymbiosis refers to one species living within another(the host) • Movement of smaller photosynthetic & heterotrophicprokaryotes into larger prokaryotic host cells • Formed cell organelles chloroplast mitochondria

  6. Prokaryotic & Eukaryotic Cells

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

  8. Classification of Life

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

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

  11. Archaebacteria

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

  13. Eubacteria

  14. Characteristics of Bacteria

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

  16. Bacterial Cell

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

  18. Sticky Bacterial Capsule

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

  20. Bacterial Structure • Infoldings of cell membrane carry on photosynthesis & cellular respiration • Infoldings called Mesosomes

  21. Mesosomes MESOSOME

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

  23. Staphylococcus Bacterial

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

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

  26. Flagella • Bacteria that are motile have appendages called flagella • Attached by Basal Body • A bacteria can have one or many flagella

  27. Flagella • Made of Flagellin • Used for Classification • Monotrichous: 1 flagella • Lophotrichous: tuft at one end • Amphitrichous: tuft at both ends • Peritrichous: all around bacteria

  28. Monotrichous Lophotrichous Amphitrichous Peritrichous

  29. Question: What is this type of bacteria ?

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

  31. Pili in Conjugation

  32. Bacterial Shapes

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

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

  35. Diplococcus

  36. Streptococcus Causes Strep Throat

  37. Staphylococcus

  38. Bacillus - E. coli

  39. Streptobacilli

  40. Spirillum

  41. Spirochetes

  42. Leptospira

  43. Bacterial Kingdoms

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

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