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MICROBIAL LIFE

MICROBIAL LIFE. CH 16. Prokaryotes. 3.5 billion years Biomass of all prokaryotes = 10x all eukaryotes Handful of soil… More prokaryotes than all the humans who have ever lived 1 – 5 μm …10 – 100 μm eukaryotic cells. Prokaryotes. Impact the World Black Death

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MICROBIAL LIFE

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  1. MICROBIAL LIFE CH 16

  2. Prokaryotes • 3.5 billion years • Biomass of all prokaryotes = 10x all eukaryotes • Handful of soil… • More prokaryotes than all the humans who have ever lived • 1 – 5 μm …10 – 100 μm eukaryotic cells

  3. Prokaryotes • Impact the World • Black Death • Tuberculosis, cholera, etc

  4. Prokaryotes

  5. Prokaryotes

  6. Prokaryotes

  7. 2 Domains • Identifying Relationships • 1 type of rRNA found in all prokaryotes & eukaryotes to compare • Marker for evolutionary relationships • Created the 2 domains of Prokaryotes • Bacteria & Archaea • Present-day archaea & eukaryotes share a common ancestor • Difficult to determine • Prokaryote genomes are mosaics of genes

  8. 2 Domains • What are the Main Differences b/w Archaea & Bacteria? • rRNA sequences • RNA polymerase • Introns • Antibiotic sensitivity • Peptidoglycan in cell wall • Membrane lipids • Histones associated w/ DNA • Conclusions?

  9. Prokaryotic Shapes • Cocci • Spherical • Streptococci • Strepthroat • Staphylococci • Bacilli • Rod-shaped • Diplobacilli • Streptobacilli • Spiral Shape • Vibrios • Corkscrew • Spirilla • Spirochetes • Syphilis

  10. Prokaryotic Shapes

  11. Prokaryotic Shapes

  12. External Structures

  13. External Structures

  14. External Structures

  15. External Structures

  16. Motility

  17. Motility • Flagella – movement • Respond to chemical or physical signals in the environment…towards or away • Scattered or concentrated at one or both ends • How it works • Lacks microtubules • Rotating rings anchored in the plasma membrane/cell wall • Rings provide rotary movement

  18. Motility

  19. Reproduction & Adaptation

  20. Reproduction & Adaptation • Asexual: • Binary Fission • New generation w/in 2-3 hrs • Optimal level is 1 gen/20 min…if continued for 3 days, colony would outweigh Earth • Reality • Repro is limited • Exhaust nutrient supply • Poison themselves • Consumed • Competition…antibiotics

  21. Reproduction & Adaptation • Endospore • Made in response to harsh conditions • Thick, protective coat that dehydrates & becomes dormant • Withstand heat/cold…whatever • Conditions improve…absorbs water and resumes growth • Interesting Info • Remain dormant for centuries • Boiling water…no problem • Autoclave…pressure cooker w/ high pressure steam • Food canning industry

  22. Reproduction & Adaptation

  23. Reproduction & Adaptation

  24. Internal Organization

  25. Internal Organization

  26. Internal Organization • Membrane Specializations • Infoldings – Cellular respiration • Thylakoid membrane – PS • Genome • 1/1000th as much DNA as eukaryote • Plasmids – may be resistant to antibiotics • Transformation • Plasmid Role • Direct the metabolism or rare nutrients • Resist antibiotics • Contingency functions • Transfer genes w/in a species and between species • Growing problem of antibiotic resistance

  27. Internal Organization

  28. Internal Organization • Ribosomes • Smaller than eukaryotic • Antibiotics can attack and block protein synthesis, but do not affect eukaryotic ribosomes • Useful for medicine

  29. Mode of Nutrition • 2 Main Sources of Energy: • Carbon • Energy • Autotrophs • Make their own • Heterotrophs • Obtain from organic compounds

  30. Metabolic Cooperation • Some prokaryotes cooperate • Anabaena • Photosynthesize & fix nitrogen • O2 inactivates nitrogen-fixing enzymes, so … • They form colonies – most cells PS while a few fix nitrogen • Biofilms – surface-coating colony • Signaling – recruit • Attachment – each other & surf. • Connections – “blood vessels” • Sulfate Bacteria & Methane Archaea • Bacteria use waste products & produce compounds that facilitate methane consumption • 300 billion kg/year

  31. Archaea Environments • Abundant in many habitats • Extreme environments too • Unusual proteins • Molecular adaptations • Both allow for them to metabolize and reproduce effectively

  32. Extreme Environments • Extreme Halophiles • 15-20% salinity…ocean is only 3% • Extreme Thermophiles • Hot water – 100ºC • Thermoacidophiles – heat & acidic environments • Methanogens • Anaerobic & give off methane • Intestines

  33. Halophiles • Locations • Great Salt Lake • Dead Sea • Seawater-evaporating ponds used to produce salt

  34. Thermophiles • Locations • Deep-ocean vents – high temps • Yellowstone National Park – acidic pools

  35. Methanogens • Locations • Anaerobic mud • Digestive tracts

  36. Moderate Archaea • Abundant in the oceans • Waters below 150 m • Equal number of bacteria below 1000 m

  37. Types of Bacteria • Proteobacteria • Gram – • Subgroup alpha • Rhizobium • Agrobacterium • Subgroup gamma • PS • Salmonella • E. coli • Subgroup delta • Slimers • Hunters at speeds of 600 km/hr

  38. Types of Bacteria • Chlamydias • Common cause of blindness • Nongonococcalurethritis or STD • Spirochetes • Many pathogenic • Syphilis • Lyme disease • Gram +: • Some are soil dwellers – actinomycetes • Cyanobacteria • PS • Bottom of the food chain

  39. PROTISTS

  40. Rise of Eukaryotic Cells • Eukaryotes evolved from prokaryotes 2 bya • 2 Step Process – Theory • Membrane Infolding • Endosymbiosis

  41. Membrane Infolding • All the membrane-enclosed organelles evolved from inward folds of the plasma membrane of a prokaryotic cell • Except mitochondria & chloroplasts

  42. Membrane Infolding

  43. Endosymbiosis • Generated the chloroplasts and mitochondria • Prokaryotes that established residence within other, larger prokaryotes • Ancestors of mitochondria • Heterotrophic prokaryotes that were able to use O2 and release large amounts of energy • Ancestors of mitochondria • Photosynthetic prokaryotes that may have come to live inside a larger host cell

  44. Endosymbiosis

  45. Endosymbiosis • Benefits • Engulfed cells enjoyed molecules & inorganic ions needed to carry out their biochemical activities • Host cells enjoyed increasing proportions of ATP & organic molecules • Eventually became interdependent…single organism

  46. Endosymbiosis • Evidence • Contain DNA, RNA & ribosomes that are similar to prokaryotes • Transcribe & translate DNA into polypeptides and enzymes • Do something similar to binary fission • 2 membranes • Alpha proteobacteria – mitochondria • Cyanobacteria - chloroplasts

  47. A Diverse Group • Protists • Mostly unicellular eukaryotes • Basically eukaryotes that are not plants, animals or fungi • Categories • Algae – PS • Protozoans – Heterotrophic • Heterotrophic & Autotrophic • Fungus-like

  48. A Diverse Group • Habitats • Most aquatic • Damp, terrestrial habitats • Moist bodies of hosts • What makes them eukaryotic?

  49. Diplomonads & Euglenozoans • Dips • Most ancient • 2 nuclei & several flagella • Modified mitochondria w/o DNA • Anaerobic • Giardiaintestinalis – drinking water contaminated w/ feces…severe diarrhea

  50. Diplomonads & Euglenozoans • Euglies • Heterotrophs, autotrophs, & patho parasites • Trypanosoma – causes sleeping sickness, spread by the tsetse fly • May be fatal if untreated; anxiety, insomnia, sleepiness, mood changes, fever, headache • Euglena – 1 or 2 flagella • PS…may also absorb nutrients as heterotrophs

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