1 / 59

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

pepper
Download Presentation

MICROBIAL LIFE

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related