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Explain the 4 requirements of a gene for phylogenetic studies and give an example of a gene or genes that meet all these criteria
- Be present in all organisms of interest
- Not laterally transferred between species
- Well conserved but still have changes
- Sufficiently large to provide enough information
- rRNAs meet these criteria (16S and 23S commonly used)
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Differentiate between a cladogram and a dichotomous key and applications of each
- Cladogram: a chart that shows relationships between organisms (that they share a common ancestor)
- Dichotomous key: organized set of mutually exclusive characteristics of organisms that can be used to determine which organism and unknown is
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Define taxonomy
The science of classifying organisms
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Give two reasons why organisms are arranged in taxonomic groups
- Classification: puts organisms into groups based on degree of relatedness
- Nomenclature: provides universal names for organisms
- Identification: provides a reference for identifying organisms
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List the three domains; give the characteristics of each, and the kinds of organisms found in each
- Bacteria: prokaryotic, peptidoglycan in cell walls
- Archaea: prokaryotic, no peptidoglycan in cell walls, extremophiles
- Eukarya: eukaryotic, cell wall varies (animalia, fungi, plantae, protista)
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Define binomial nomenclature, explain the importance of scientific names and give examples of bacterial names
- Genus + specific epithet
- Used worldwide, identical no matter where you are
- Escherichia coli, staphylococcus aureus
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Give the order of taxonomic groups from the most general to the most specific (current taxonomic hierarchy)
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
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List the 4 eukarya kingdoms, list characteristics used to differentiate among them, and give examples from each
- Animalia: multicellular, heterotrophic, no cell walls (sponges, worms, insects, vertebrates)
- Plantae: multicellular, cellulose cell walls, usually photoautotrophic (algae, mosses, ferns, confiers, flowering plants)
- Fungi: chemoheterotrophic, unicellular OR multicellular, cell walls of chitin, develop from spores
- Protistsa: catchall for eukaryotic organisms that do not fit into other kingdoms (slime molds, algae, protozoa)
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Define: genus, species (bacterial species), strain, clone
- Genus: Set of closely related species
- species: population of cells with similar characteristics
- Clone: population of cells derived from a single cell
- Strain: genetically different cells within a clone
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List and discuss the methods of classifying and identifying microorganisms
- Morphological characteristics
- differential staining
- biochemical tests
- serology (antiserum+bacterium)
- phage typing (using viruses)
- DNA base composition
- DNA fingerprinting (gel electrophoresis)
- rRNA sequencing
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Describe the basis of chemical tests, serology, and phage typing
- Chemical tests: determines enzymatic activites, tests for presence or absence of a specific enzyme, selective and differential media
- Serology: combines known antiserum with unknown bacteria (slide agglutination, Enzyme-linked immunosorbent assay - contains enzyme substrate, and Western blot - uses antibodies)
- Phage typing: uses viruses to identify bacteria (viruses are hyper specific)
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