Lecture 20: Microbial Systematics and Diversity Flashcards Preview

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

Flashcards in Lecture 20: Microbial Systematics and Diversity Deck (35)
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1

What is the era of heavy bombardment?

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

2

How did the formation of a hospitable earth occur?

End of era of heavy bombardment cause temp decrease

Geological and Ocean Development

3

What is the subsurface hypothesis for the origin of life?

First life evolved in hydrothermal vents
-warm water w/ lots of nutrients
-No UV radiation
-stable temperature

4

What is the early evidence of cellular life?

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

Microbial Fossils
-­“Microfossils”

Microbial Forms Preserved In Ancient Rock

5

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

At least 3.5 Billion years ago

Conditions
-Liquid water
-Temp (0-100 degrees)
-Anoxic atmosphere

6

What were the early types of microbial metabolism?

Anaerobic and Autotrophic b/c
-anoxic ocean and atmosphere
-mostly inorganic chemicals present

7

What were the early metabolism types that used light energy?

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

8

What is the chemical reactions for oxygenic and anoxygenic phototrophy?

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

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

9

What is the great oxidation event?

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

10

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

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+)

11

How is endosymbiosis significant to eukaryotes and plants?

Free living bacteria made their way into eukaryotes/plants

Chloroplast = cyanobacteria
Mitochondria = proteobacteria

12

What are the characteristics of mitochondria and chloroplasts?

-­Contain Their Own DNA
-­Have Circular DNA (like prokaryotes)
-­Have Small Ribosomes (70S) (like prokaryotes)

13

How do mitochondria and chloroplasts produce energy?

Mitochondria -> Consume O2 -> Energy

Chloroplast -> Produce O2 -> Energy from Sun

14

What are the unifying features of domain archaea?

Traits Shared by All Archaea
-Ether-­‐Linked Lipids
-Lack of Peptidoglycan
-Complex RNA Polymerases

15

What traits are only found in domain archea?

Methanogenesis
-Conserving energy from the production of methane

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

16

What kinds of habitats are archaea found in?

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

Extreme salinity
-Salt lakes and salterns

17

What are the only gram-positive bacteria?

Actinobacteria, Firmicutes, and Mollicutes

18

How many culture strains and uncultured strains of bacteria?

Culture Strains ~18 phyla
Uncultured Strains >80 phyla

19

What are the ancient bacterial phyla that are hyperthermophiles?

Aquificae
-Most Heat Tolerant (95°C)
-Aerobic Hyperthermophile

Thermotoga
-Anaerobic Hyperthermophile
-20% of Genes from Archaea

Thermodesulfobacterium
-Ether-­‐Linkage Lipids

20

What is Deinococcus-Thermus?

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

What are Deinococcus radiodurans used for?

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

What are spirochetes?

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

What kinds of spirochetes are pathogens?

Treponema allidum = Syphilis

Borrelia burgdorferi = Lyme Disease

24

What is the Genus Bacteriodetes?

Common in Intestinal Tract of Animals
-Most Common Species in Human Gut
-­Break Down Polysaccharides (plant matter)

25

What are some familiar proteobacteria?

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

What are some unique proteobacteria?

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

What are some non-endospore forming genera of firmicutes?

Genus Staphylococcus
-MRSA

Genus Streptococcus
-­Dental caries

Genus Listeria
-­Food infection

Genus Lactobacillus
-­Lactic Acid Bacteria

28

What are some endospore forming genera of firmicutes?

Genus Bacillus
-B. anthracis = Biological Weapon
-­B. thuringiensis = Bt Toxin
-­B. subtilis = Host Cell

Genus Clostridium
-­C. botulinum = Botulism
-­C. tetani = Tetanus

29

What are some general features of actinobacteria?

Rod shaped or filamentous
Primarily aerobic and found in soil

Notable Pathogens = mycobacteria
Antibiotic producers = streptomyces

30

What is microbial taxonomy?

Identifying, classifying and naming Microorganisms
-historically based on phenotypes
-now based on metabolism, physiology, chemical characteristics