Lecture 3 Flashcards
What is taxonomy?
science of classifying organisms
- degrees of similarity between organisms
What is systematics or phylogeny?
study of evolutionary history of organisms
What did Carl Linnaeus do in 1735?
- basis for biological classification
Kingdom -> class -> order
What did Charles Darwin do in 1895?
developed phylogenetic tree that represents evolutionary relationships
What does the phylogenetic tree tell us?
grouping organisms by common properties
- common ancestor
What are the 3 domains?
Bacteria
Archaea
Eukarya
What are some characteristics of bacteria?
- simple unicellular organisms
- unique cell walls
What are some characteristics of archaea?
- unicellular organisms with distinct genetics
- unique membrane lipids and ribosomal RNA sequences
- can live in extreme environments
What are some properties of eukarya?
- cells with DNA in a separated nucleus
- exist in animals, plants, fungi
Where is the origin of eukaryotes?
infoldings of prokaryotic plasma membranes to form complex internal structures
What is the endosymbiotic theory?
mitochondria and chloroplasts originated from symbiotic relationships with free-living bacteria engulfed by early eukaryotic cells
What is a taxonomic hierarchy?
developed by Linnaeus to classify plants and animals
- domain, kingdom, phylum, class, order, family, genus, species
What is the eukaryotic species?
group of closely related organisms that breed among themselves
What does binomial nomenclature have?
genus and specific epithet (species)
What is proper nomenclature formatting?
1) Genus capital
2) species lower case
3) Italicized or underlined
- Enterococcus faecalis
- E. faecalis
How are prokaryotic species classified?
- culture: bacteria grown in lab
- clone: population of cells derived from single parent cell
- strain: genetically different cells within a clone
What is protista?
catchall kingdom for organisms
- both autotrophic and heterotrophic
- grouped into clades based on rRNA
What is fungi?
- chemoheterotrophic
- uni/multicellular
- chitin cell walls
- develop from spores or hyphal fragments
What are plantae?
- multicellular
- cellulose cell walls
- photosynthesis
What are animalia?
- multicellular
- no cell walls
- chemoheterotrophic
Why can’t viruses be classified?
not composed of cells
- requires a host cell
What are viral species?
population of viruses with similar characteristics that occupies a particular ecological niche
Differentiate between classification and identification.
Classification: grouping of related species
Identification: matching characteristics of an unknown to a list of known organisms
What is Bergey’s Manual of Determinative Bacteriology?
Provides identification schemes for identifying bacteria and archaea
What are morphological characteristics?
used for identifying prokaryotes and eukaryotes
What is differential staining for?
identifying bacteria with cell walls
What is transport media?
used to collect and transport pathogens to a laboratory
What are biochemical tests used for?
to determine presence of bacterial enzymes
What are the 3 morphologies for protist and bacteria?
cocci
bacilli
spirillium
What are the grouping prefixes?
diplo: double
strepto: chain
staphylo: cluster
What is a clade?
group of organisms with one common ancestor and all its descendants
How are clades formed?
based on shared evolutionary traits
What is gram stain? What do the results tell us?
differentiates bacteria based on cell wall structure
- gram positive: thick peptidoglycan layer (purple)
- gram negative: thin peptidoglycan layer (pink/red)
What is endospore stain? What do the results tell us?
identifies bacteria that produce endospores
- endospores = green
- cell is pink/red
What is capsule stain? What does it show us?
detects presence of capsule
- capsule = clear halo around the cell
What is acid-fast stain? What does it show us?
Identifies bacteria with waxy cell wall
- acid-fast bacteria = red
- non-acid-fast bacteria = blue
What is carbohydrate fermentation test? What does it indicate?
whether bacteria can ferment specific sugars to produce acid and gas
- indicates acid and gas production
What is serology?
study of serum and immune responses in serum
What happens in antiserum?
solution of antibodies are tested against an unknown bacteria
What happens in a slide agglutination test?
bacteria stick together when mixed with antibodies produced in response to the bacteria
What is the purpose of serological testing?
differentiate between species and strains within species
What is ELISA?
(enzyme-linked immunosorbent assay)
a test used to identify unknown bacterium using known antibodies
What is western blotting? What does it confirm?
identifies antibodies in a patient’s serum
- confirms HIV and Lyme disease
What is phage typing used for?
to determine which phages a bacterium is susceptible to
What is DNA fingerprint? How does it give us genetic information?
- Electrophoresis of restriction enzyme digests of an organism’s DNA
- compares fragments from ladder and different organisms to find the match
What are the equations for DNA base pairing?
CG + AT = 100%
C = G
A = T
What does nucleic acid hybridization measure?
ability of DNA strands from one organism to hybridize with DNA strands of another organisms
What is the relationship of hybridization to relatedness?
greater degree of hybridization = greater degree of relatedness
- >70% hybridization = same species
What is NAATs? (nucleic acid amplification tests)
to amplify DNA of an unknown that cannot be cultured
How does PCR work?
1) heat to separate strands
2) strands combine
3) cool for renaturation
4) determine degree of hybridization
What is a DNA chip?
contains DNA probes and detects pathogens by hybridization between probe and DNA in the sample
What are dichotomous keys?
identification keys based on successive questions
What are cladograms?
maps that show evolutionary relationships among organisms based on rRNA sequences
