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BIO 425: Microbiology > Lecture 20: Microbial Systematics and Diversity > Flashcards

Lecture 20: Microbial Systematics and Diversity Flashcards

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Biology 101 flashcards
1
Q

What is the era of heavy bombardment?

A

First 500 Million Years of Earth

No Evidence of Life

  • ­Temperatures Too High
  • ­Intense UV Radiation
  • ­Collisions With Asteroids/Rocks

Water On Earth
-­Collisions With Icy Comets

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2
Q

How did the formation of a hospitable earth occur?

A

End of era of heavy bombardment cause temp decrease

Geological and Ocean Development

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3
Q

What is the subsurface hypothesis for the origin of life?

A

First life evolved in hydrothermal vents

  • warm water w/ lots of nutrients
  • No UV radiation
  • stable temperature
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4
Q

What is the early evidence of cellular life?

A

Stromatolites

  • ­Layered Mixtures of Microbes – “Microbial Mats”
  • ­Trap Mineral Materials – Fossilize

Microbial Fossils
-­“Microfossils”

Microbial Forms Preserved In Ancient Rock

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5
Q

How long ago did microbial life first appear? What conditions were compatible w/ life?

A

At least 3.5 Billion years ago

Conditions

  • Liquid water
  • Temp (0-100 degrees)
  • Anoxic atmosphere
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6
Q

What were the early types of microbial metabolism?

A

Anaerobic and Autotrophic b/c

  • anoxic ocean and atmosphere
  • mostly inorganic chemicals present
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7
Q

What were the early metabolism types that used light energy?

A

Phototrophy (Anoxygenic)

  • ­Energy Source = Sun
  • ­Electron Donor = Hydrogen Sulfide (H2S)
  • ­Carbon Source = CO2

Phototrophy (Oxygenic)

  • ­Energy Source = Sun
  • ­Electron Donor = Water (H2O)
  • ­Carbon Source = CO2
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8
Q

What is the chemical reactions for oxygenic and anoxygenic phototrophy?

A

Phototrophy (Anoxygenic)
Inorganic Carbon + H2S + Light -> Organic Carbon +
Elemental Sulfur

Phototrophy (Oxygenic)
Inorganic Carbon + H2O + Light -> Organic Carbon +
Oxygen (O2)

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9
Q

What is the great oxidation event?

A

2.5 billion years ago where atmosphere gets O2

Aerobic Respiration Possible
-Major Pathway of Most Life On Earth Today

Formation of the Ozone (O3) Layer
-Barrier to Ultraviolet Radiation from the Sun

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10
Q

What took so long for the great oxidation event to occur?

A

Cyanobacteria Produced Oxygen For 500 Million Years Before Change In Atmosphere

  • ­Oxygen Consumed By Iron Minerals in the Ocean
  • ­Iron Oxidation: Ferrous (Fe2+) -> Ferric (Fe3+)
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11
Q

How is endosymbiosis significant to eukaryotes and plants?

A

Free living bacteria made their way into eukaryotes/plants

Chloroplast = cyanobacteria
Mitochondria = proteobacteria
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12
Q

What are the characteristics of mitochondria and chloroplasts?

A
  • ­Contain Their Own DNA
  • ­Have Circular DNA (like prokaryotes)
  • ­Have Small Ribosomes (70S) (like prokaryotes)
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13
Q

How do mitochondria and chloroplasts produce energy?

A

Mitochondria -> Consume O2 -> Energy

Chloroplast -> Produce O2 -> Energy from Sun

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14
Q

What are the unifying features of domain archaea?

A

Traits Shared by All Archaea

  • Ether-­‐Linked Lipids
  • Lack of Peptidoglycan
  • Complex RNA Polymerases
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15
Q

What traits are only found in domain archea?

A

Methanogenesis
-Conserving energy from the production of methane

Life in Extreme Heat
-­Only organisms in environments >100˚C

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16
Q

What kinds of habitats are archaea found in?

A

Extreme cold or heat
-antarctic sea ice, volcanic hot springs, hydrothermal vents

Extreme salinity
-Salt lakes and salterns

17
Q

What are the only gram-positive bacteria?

A

Actinobacteria, Firmicutes, and Mollicutes

18
Q

How many culture strains and uncultured strains of bacteria?

A

Culture Strains ~18 phyla

Uncultured Strains >80 phyla

19
Q

What are the ancient bacterial phyla that are hyperthermophiles?

A

Aquificae

  • Most Heat Tolerant (95°C)
  • Aerobic Hyperthermophile

Thermotoga

  • Anaerobic Hyperthermophile
  • 20% of Genes from Archaea

Thermodesulfobacterium
-Ether-­‐Linkage Lipids

20
Q

What is Deinococcus-Thermus?

A

Genus Thermus
-­T. aquaticus -> Taq Enzyme

Genus Deinococcus

  • ­D. radiodurans
  • Soil and Dust Particles
  • Survives Intense Radiation (15,000 grays; 10 kills humans)
  • Resistant to Mutagenic Compounds
21
Q

What are Deinococcus radiodurans used for?

A

DNA Repair Enzymes

  • Single or Double-­‐Stranded Breaks
  • ­Repair Misincorporated Bases

DNA Arrangement

  • ­Cells Always in Pairs
  • ­DNA Stored in Nucleoids
  • ­Repair By Nucleoid Fusion
22
Q

What are spirochetes?

A

Motile, Tightly-­‐Coiled Bacteria

  • Rare Example of Morphology Predicting Phylogeny
  • Common in Aquatic Habitats and Animal Hosts

Contain Endoflagella

  • Remain in Periplasm of the Cell
  • ­Rotation Provides Torque Motility
23
Q

What kinds of spirochetes are pathogens?

A

Treponema allidum = Syphilis

Borrelia burgdorferi = Lyme Disease

24
Q

What is the Genus Bacteriodetes?

A

Common in Intestinal Tract of Animals

  • Most Common Species in Human Gut
  • ­Break Down Polysaccharides (plant matter)
25
Q

What are some familiar proteobacteria?

A

Genus Escherichia
-Intestinal Tract of Animals, Some Pathogenic

Genus Salmonella

  • Closely Related to Esherichia,
  • Most Pathogenic

Genus Vibrio

  • V. chloerae ·∙
  • Pathogenic

Genus Aliivibrio

  • A. fisherii ·∙
  • Symbiont
26
Q

What are some unique proteobacteria?

A

Magnetic Bacteria

  • Magnetosprillum magnetotacticum
  • Contains Iron Minerals in Magnetosomes
  • Detect and Respond to Magnetic Fields

Predatory Bacteria

  • Bdellovibrio spp.
  • “Bdello” = Leech
  • Prey on Other Bacteria
27
Q

What are some non-endospore forming genera of firmicutes?

A

Genus Staphylococcus
-MRSA

Genus Streptococcus
-­Dental caries

Genus Listeria
-­Food infection

Genus Lactobacillus
-­Lactic Acid Bacteria

28
Q

What are some endospore forming genera of firmicutes?

A

Genus Bacillus

  • B. anthracis = Biological Weapon
  • ­B. thuringiensis = Bt Toxin
  • ­B. subtilis = Host Cell

Genus Clostridium

  • ­C. botulinum = Botulism
  • ­C. tetani = Tetanus
29
Q

What are some general features of actinobacteria?

A

Rod shaped or filamentous
Primarily aerobic and found in soil

Notable Pathogens = mycobacteria
Antibiotic producers = streptomyces

30
Q

What is microbial taxonomy?

A

Identifying, classifying and naming Microorganisms

  • historically based on phenotypes
  • now based on metabolism, physiology, chemical characteristics
31
Q

What must occur when classifying new species and identifying nomenclature?

A

MUST be:

  • cultured
  • deposited in two culture collections
  • be published
32
Q

How are genotypes used to identify microbes?

A

DNA Sequence data used
-either single genes or whole genomes

Single Gene
-16S rRNA Gene -> “Golden Marker”

Whole Genome Comparison
-Quantify % match

33
Q

What is the biological species concept?

A

Species = interbreeding Population of Organisms

Does Not Apply To Prokaryotes (Asexual)

34
Q

What is the phylogenetic species concept?

A

Species = Cluster of Microbes Distinct From Other Groups Based on Phylogenetic Analysis

35
Q

How do we define a species by genetic data?

A

16S rRNA = At Least 97% Similar

DNA-­DNA Hybridization = At Least 70% Similar

BIO 425: Microbiology (22 decks)

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