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Prokaryotes

Prokaryotes. Chapter 27. Kingdom Monera. Prokaryotes Unicellular (Single-celled) organisms that lack membrane-bound organelles and nuclei Divided by 1. Domain 2. Nutritional Classification 3. Reactivity with Oxygen. Domain Classification. Nutritional Classification. AUTOTROPHS

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Prokaryotes

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  1. Prokaryotes Chapter 27

  2. Kingdom Monera • Prokaryotes • Unicellular (Single-celled) organisms that lack membrane-bound organelles and nuclei • Divided by 1. Domain 2. Nutritional Classification 3. Reactivity with Oxygen

  3. Domain Classification

  4. Nutritional Classification AUTOTROPHS • Photoautotrophs • Photosynthetic autotrophs – Like plants • Light energy  Energy (ATP) • Carbon dioxide  organic compounds (Glucose) • Chemoautotrophs • Inorganic substances  Energy (ATP) • Carbon dioxide  organic compounds (Glucose

  5. Nutritional Class (Page 2) HETEROTROPHS • Photoheterotrophs • Light energy  Energy (ATP) • Get carbon from consuming other organisms • Chemoheterotrophs • Get both carbon & energy from consuming other organisms

  6. Reactivity with Oxygen • Whether they must react with O2, must be in absence of O2, or they can be in absence or not of O2 • Obligate aerobe – Require O2 for respiration • Obligate anaerobe – O2 is a poison to them • Facultative anaerobe – Prefer to use O2, but don’t need to use it to live

  7. Questions • Which of the 3 classifications is appropriate for humans? • What would you call something that uses light for energy, but must obtain carbon in an organic form? • Aerobes would do what form of catabolism? • What about anaerobes?

  8. Roles of Prokaryotes • Decomposers – recycle dead organic manner • Pathogens – organisms that cause disease • Nitrogen Fixation • Atmospheric N2 NH4 • ONLY way to fix nitrogen into organic systems • Play a vital role in genetic engineering • E. Coli is used to manufacture human insulin

  9. Bacteria’s Roles (Page 2) • Symbionts in the gut – Manufacture vitamins • Digest cellulose • Digest Food • Bioremediation – remove pollutants • Used in production of cheese & yogurt

  10. Symbiotic Roles • Symbiotic – relationships with other species • Mutualism – Both symbionts benefit • Pollinators & Flowering plants • Commensalism – One organism benefits other is unharmed • Fern growing in the shade of a tree • Parasitism – One benefits at the expense of another

  11. Antibiotics • Chemicals that kill prokaryotes • Usually produced by fungi • NOT effective against viruses • Many plasmids confer resistance to different antibiotics • MDR-TB – Multi-Drug Resistant (resistant to multiple antibiotics) Tuberculosis bacteria • XDR-TB – eXtremely-Drug Resistant (resistant to almost every antibiotic) Tuberculosis bacteria

  12. Archaebacteria • Unicellular • Prokaryotes • No Peptidoglycan in their cell walls • Able to live in extreme environments • Resemble the first cells on Earth • Extreme Halophiles– Salt lovers • Extreme Thermophiles – exist in extreme temperatures (high temperatures) • Methanogens – Use CO2 to oxidize H2 • Produce methane as a by product

  13. Examples of Archaebacteria Hot Springs - Thermophiles Thermoacidophiles

  14. Eubacteria • Broadly categorized as Gram-negative or Gram-positive • Due to whether the bacterium is able to take up Gram’s stain • Gram-positive – large amount of peptidoglycan in cell wall • Susceptible to antibiotics • Gram-negative – structurally more complex cell wall • Contains less peptidoglycan • Outer membrane contains lipopolysaccharides

  15. 5 Important Bacterial Subgroups • Proteobacteria • Chlamydias • Spirochetes • Gram-Positive Bacteria • Cyanobacteria

  16. Proteobacteria • Includes photoautotrophs, chemoautotrophs, and heterotrohps • Some are aerobic, others are anaerobic • Nitrosomonas – Nitrogen fixing bacteria • Examples: • Escherichia coli (E coli) – benign & pathogenic • VibrioCholerae – Cholera • Rhizobium – live in roots of legumes

  17. Chlamydias, Spirochets • Gram-negative like proteobacteria • Chlamydias • ALL are parasitic • Lack peptidoglycan • Chlamydia = most common STD or VD • Spirochetes • Helical shape • Move by rotating internal flagella-like filaments • Syphilis and Lyme disease • Others are free-living (not parasitic or pathogenic)

  18. Gram-positive Bacteria • Diversity rivals proteobacteria • Streptomyces – source of many antibiotics • Bacillus anthracis • Clostridium botulinum • Mycoplasms – bacteria that lack cell walls (WTF?) • Synthetic organism?

  19. Cyanobacteria • ONLY photoautotrophs • Plant-like photosynthesis • May have heterocytes – can fix nitrogen

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