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32 Cards in this Set
- Front
- Back
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Definition of a Microbe?
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Organism that usually cannot be seen with the naked eye.
≤0.1mm = 100 µm Cellular and noncellular |
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Role of Microbes in environment
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High diversity, numbers and biomass
photosynthesis major recyclers biogeochemical cycles produce/consume greenhouse gases |
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Impact of microbes on humans
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Disease in plants/animals
Normal flora Agriculture Food and beverage Bioremediation Fuel source Industry (enzymes, antibiotics, chemicals) |
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How old is the planet?
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4.6 billion years
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How long ago did the first prokaryotic cell originate?
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3.8 bya
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how long ago did the first eukaryotic cell originate?
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2 bya
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What microbial group was the first oxygenic photosynthesizer to evolve?
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Oxygenic photosynthetic bacteria:
3 bya, cyanobacteria Oxygenic photosynthetic eukaryotices: 1.5 bya, algae |
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Where do bacteria exist?
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Nearly everywhere;
Water necessary |
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How many total bacteria are thought to inhabit the planet?
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10^30
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van Leeuwenhoek
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Significantly improved quality of microscope lenses
First to observe very small microbes, including bacteria |
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Pasteur
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Father of microbiology
Disproved spontaneous generation Described scientific basis of fermentation Developed pasteurization developed several vaccines, including rabies |
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Robert Koch
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Demonstrated certain diseases caused by microbes
Developed criteria used to prove a disease is caused by a specific microbe (Koch's postulates) |
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Edward Jenner
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1789: first to develop vaccine (small pox)
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Carl Woese
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Described taxonomy based on evolutionary relationships
Molecules are documents of evolutionary history Taxonomy based on genotype Discovered archaea |
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Koch's Postulates
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To show cause of a particular disease
1) pathogen present in every case 2) pathogen isolated from diseased host and grown in pure culture 3) pathogen inoculated into healthy host causes same disease 4) organism must be re-isolated and shown to be same organism |
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Problems with Koch's postulates
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Lack of animal model
Several pathogens cannot be grown in culture |
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Carl Woese's important discoveries
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Three domains of life: bacteria, archaea, and eukarya
2/3 domains have prokaryotic cell types archaea more evolutionary related to eukarya than to bacteria Discovered archaea |
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How did Carl Woese's work change how life is categorized?
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Regrouped into three domains, based on evolutionary relatedness (genotype)
(previously based on phenotype) |
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How to write genus, species name
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Underlined or italicized
Genus capitalized, species lowercase |
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Similarities and differences between bacteria and archaea
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Cannot be distinguished with microscope
Similarities: Lack nucleus and complex cell structure of eukarya Small size simple shapes high metabolic diversity asexual reproduction Differences: Bacteria have peptidoglycan in cell walls, archaea have none |
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Domain Bacteria
General characteristics |
Prokaryotes (no nucleus)
Small cells; simple shapes Unicellular Asexual reproduction Cell wall = peptidoglycan Generates energy using light, organic chemicals or inorganic chemicals (depends on species) Can grow in wide variety of conditions Some are pathogens |
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Domain Archaea
General characteristics |
Prokaryotes
If cell walls, no peptidoglycan Many similar properties as Bacteria: Lack nucleus & complex cell structure of Eukarya Small size Simple shapes High metabolic diversity Asexual reproduction Distinct from Bacteria: more similar to Eukarya biochemically & genetically All unicellular NO KNOWN PATHOGENS |
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Domain Eukarya
General characteristics |
Most unicellular
Larger than prokaryotes, more varied cell shapes Some are pathogens |
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Eukarya: Protista
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Protozoa: first animal
lack cell walls sexual &/or asexual reproduction some independent, some parasites algae=photosynthetic |
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Eukarya: Fungi
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Eukaryotic cell type
not plants! no photosynthesis absorb organics for food cell walls of chitin sexual and asexual reproduction some are pathogens Unicellular yeasts multicellular molds mushrooms make hyphae |
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Eukarya: Plantae
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NO pathogens
Photosynthetic Cell walls of cellulose Multicellular or Unicellular |
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Eukarya: Animalia
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Multicellular
Lack cell walls Non-photosynthetic Ingest other cells for food Mostly macroscopic |
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Which domain do viruses belong?
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None
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Binomial nomenclature
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Developed by carolus linnaeus (1735)
Latin names; taxonomy |
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rRNA
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Ribosomal RNA
All organisms have rRNA in cells Ribosomes perform same essential functions in all cells--make proteins Genes encoding rRNA contain: conserved region (allows gene to be identified easily) variable region (determines evolutionary relationships) |
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taxonomy
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science of classification
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phylogeny
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evolutionary relationships between organisms.
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