prokaryotes chapter 27. slide 2 of 20 kingdom monera prokaryotes unicellular (single-celled)...
TRANSCRIPT
Prokaryotes
Chapter 27
Slide 2 of 20
Kingdom Monera
Prokaryotes Unicellular (Single-celled)
organisms that lack membrane-bound organelles and nuclei
Divided by 1. Domain2. Nutritional Classification3. Reactivity with Oxygen
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Domain Classification
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Nutritional Classification
AUTOTROPHS
1. Photoautotrophs Photosynthetic autotrophs – Like plants Light energy Energy (ATP) Carbon dioxide organic compounds (Glucose)
2. Chemoautotrophs Inorganic substances Energy (ATP) Carbon dioxide organic compounds (Glucose
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Nutritional Class (Page 2)
HETEROTROPHS
3. Photoheterotrophs Light energy Energy (ATP) Get carbon from consuming other organisms
3. Chemoheterotrophs Get both carbon & energy from consuming other
organisms
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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
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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?
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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
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Bacteria’s Roles (Page 2)
Symbionts in the gut – Manufacture vitamins Digest cellulose Digest Food
Bioremediation – remove pollutants
Used in production of cheese & yogurt
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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
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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
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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
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Examples of Archaebacteria
Thermoacidophiles
Hot Springs - Thermophiles
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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
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5 Important Bacterial Subgroups
Proteobacteria
Chlamydias
Spirochetes
Gram-Positive Bacteria
Cyanobacteria
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Proteobacteria
Includes photoautotrophs, chemoautotrophs, and heterotrohps
Some are aerobic, others are anaerobic
Nitrosomonas – Nitrogen fixing bacteria
Examples: Escherichia coli (E coli) – benign & pathogenic Vibrio Cholerae – Cholera Rhizobium – live in roots of legumes
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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)
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Gram-positive Bacteria
Diversity rivals proteobacteria
Streptomyces – source of many antibiotics
Bacillus anthracis
Clostridium botulinum
Mycoplasms – bacteria that lack cell walls (WTF?) Synthetic organism?
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Cyanobacteria
ONLY photoautotrophs
Plant-like photosynthesis
May have heterocytes – can fix nitrogen