Classification of Microbes (Lec. 9) Flashcards
Use the binomial nomenclature system
Genus species, all italicized, Genus capitalized
Summarize the taxonomic hierarchy from domain to species
Domain, Kingdom, Phylum, Class, Order, Family, Genus, species
Define taxonomy
the branch of science concerned with classification of organisms
Define taxon
a taxonomic group of any rank, such as a species, family, or class
Define phylogeny
the study of the evolutionary history of organisms
Define culture
the growth of microorganisms in a lab under specific conditions
Define clone
a cell, tissue, or organism that is an exact genetic replica of another cell, tissue, or organism
Define strain
a genetic variant, subtype, or culture within a biological species.
Define protist
a single-celled organism of the kingdom Protista in the domain Eukarya
List the characteristics of the Bacteria domain
Prokaryotic; cell wall contains peptidoglycan; membrane lipids are composed of straight carbon chains attached to glycerol by ester linkage; first amino acid in protein synthesis is Formylmethionine; susceptible to antibiotics; has an rRNA loop and a common arm of tRNA; reproduce through binary fission
List the characteristics of the Archaea domain
Prokaryotic; cell wall varies in composition but contains no peptidoglycan; membrane lipids are composed of branched carbon chains attached to glycerol by ether linkage; first amino acid in protein synthesis is methionine; resistant to antibiotics; does not have an rRNA loop or a common arm of tRNA; reproduce through binary fission
List the characteristics of the Eukarya domain
Eukaryotic; cell wall varies in composition but contains carbohydrates; membrane lipids are composed of straight carbon chains attached to glycerol by ester linkages; first amino acid in protein synthesis is methionine; no rRNA loop but does have a common arm of tRNA; reproduce sexually or asexually
Differentiate between identification and classification
Identification is matching characteristics of an unknown organism to lists of known organisms. Classification is placing organisms in groups of related species
Describe how a newly discovered microbe can be classified by DNA sequencing
DNA sequencing determines the precise order of nucleotides, and the resulting sequence can be compared to known microbial DNA sequences to identify the organism’s closest relatives.
Describe how a newly discovered microbe can be classified by DNA fingerprinting
DNA fingerprinting focuses on confirmation of the identity of individual organisms, and compares the DNA of the organism to known species
Describe how a newly discovered microbe can be classified by NAAT
Nucleic acid amplification tests like PCR can create many copies of a small sample of DNA, and therefore make it easier to study and classify.
Describe how microorganisms can be identified by nucleic acid hybridization
There are many different methods of nucleic acid hybridization, but they all involve exposing a DNA sample to a DNA probe with a tag, which can find and label any DNA sequences complementary to its DNA.
Describe how microorganisms can be identified by Southern blotting
Southern blotting is a type of nucleic acid hybridization in which DNA fragments are separated by size by gel electrophoresis, then transferred to a membrane, then exposed to a labeled DNA probe with a radioactive, fluorescent, or chemical tag.
Describe how microorganisms can be identified by DNA microarrays
DNA microarrays are a type of nucleic acid hybridization in which a chip with specific complementary DNA sequences is mixed with a DNA sample that has been fluorescently dyed. A machine is used to measure the intensity of the fluorescence at each sequence on the chip.
Describe how microorganisms can be identified by ribotyping
Ribotyping specifically looks at the rRNA genes, through gel electrophoresis and analysis of the banding pattern. Useful when figuring out domain or phylum; but less useful for anything more specific.
Explain serology in terms of classifying and identifying microorganisms
Serology is the study of what is in a patient’s serum; can determine through immunological methods (lab techniques involving the interaction of antigens with specific antibodies) if a patient has certain antigens or antibodies in their blood. Useful for bacteria, few fungi, protozoa (very rare), and viruses
Differentiate a dichotomous key from a cladogram
A dichotomous key is an identification key based on successive questions; each question has two possible answers. A cladogram is a map that shows evolutionary relationships among organisms (based on rRNA sequences).
