Notes Module 1 (pt 1) Flashcards
Define Taxonomy
Science of biological classification; consists of classification, nomenclature, & identification
Define Classification
Arrangement of organisms into groups based on mutual similarity or evolutionary relatedness
Define Nomenclature
The assignment of names to taxonomic groups and members of groups
Define Identification
The process of determining that a particular organism or isolate belongs in a taxonomic classification; based on cellular characteristics such as chemical composition, morphology (appearance), biochemical activity, antigens
Define Eucaryotic Cell Type
- Has nuclear membrane
- Has multiple, linear chromosomes
- Replicates the cell through mitosis
- Produces energy in the mitochondria
- Has several specialized organelles (golgi appratus, endoplasmic reticulum, etc..)
Define Procaryotic Cell Type
- No nuclear membrane
- Has One, circular chromosome
- Replicates the cell through binary fission (membrane attachment)
- Produces energy on cytoplasmic membrane (no mitochondria)
- Has few specialized organelles (ribosomes)
Parasitic worms classification
Eucaryotic
Protozoa and algae classification
Eucaryotic
Fungi: molds and yeast classification
Eucaryotic
Bacteria classification
Procaryota (procaryotic)
Viruses classification
classified separately; do not fit into any official kingdom because they are not living organisms
Define the nomenclature, Genus
1) Classification level of common usage subdivision of Family
(2) Contains members with many similarities
(3) Written/spoken first; Underline if not italicized
(4) Example: Staphylococcus (underlined)
Define the nomenclature, Species
(1) Subdivision of genus
(2) Contains members having many similarities, but enough differences to be distinctly different
(3) Written/spoken last (after genus). Underline if not italicized
(4) When written as “species” or “spp.” it refers to several/all members of the genus
(5) Example: Staphylococcus aureus (both underlined) or Staphylococcus (underlined) spp.
Define the nomenclature for Strain and Variety
Subdivisions or alternate forms of species based on morphologic or biochemical differences
Define Antigen
A significant surface molecule against which antibodies are made and which can be used for identification.
A Procaryotic cell is a ___________
Single cell organism without formed nucleus (no nuclear membrane) or organelles such as possessed by higher organisms
The diameter of a procaryotic cell is
0.5 to 0.8 um, some up to 1.5 um
The length of a procaryotic cell is
1 to 6 um; most about 1 to 2 um
One micrometer (um) is _____ mm or _______ meter or _____ inch
1/1000mm; 1/1,000,000 meter; 1/25,400 inch
Define Morphology
The external appearance of the cell, colony, or other item.
Observation of cell is usually done after _____
Performing the Gram stain and observing at 1000 power magnification
Gram-positives are stained____
Blue to purple
Gram-negatives are stained_____
Pink to red
What is the composition of Endospores?
concentrated, dehydrated, densely packed nucleic acids and metabolic
proteins within a thick spore coat
What is the composition of Capsules?
Polysaccharides
Describe Flagellum
Long slender threadlike appendage several times the length of the cell
What is the composition of Flagellum?
Protein
What are the functions of Flagellum?
(a) Motility – propel the bacterium; provide locomotion
(b) Moves toward a favorable environment and away from adverse ones
Types: Chemotaxis; Phototaxis
What is chemotaxis?
movement of an organism in response to a chemical stimulus
What is phototaxis?
movement of an organism in response to light
How do Spirochetes move?
by means of axial filaments, bundles of fibrils arising at ends of cell beneath outer sheath and spiral around the cell – causes corkscrew motion
Define Saprophyte
an organism which utilizes non-living organic matter
Define Parasite
an organism which lives in or on a host organism from which it secures some advantage such as deriving organic nutrients from a living host
Define Fastidious
organisms that have elaborate requirements for specific nutrients which they cannot synthesize, e.g. vitamins and other growth-promoting substances.
Define Nutrient
a growth-supporting substance taken by a cell from its environment and used in metabolic activities, i.e. a food substance
Define Growth Factors
various organic compounds such as hemin, specific amino acids, vitamins, etc. which fastidious organisms are unable to synthesize but with which they must be supplied; often results from the lack of genes for certain metabolic enzymes
Define Cultivation (of bacteria)
the growth of particular microorganisms; usually under controlled
conditions, e.g. temperature, pH, nutrients
What are the five environmental needs of bacteria?
- Oxygen utilization (with or without)
- Temperature
- pH
- Humidity
- CO2 (for some)
Define Culture media
The material in/on which bacteria grows in the laboratory;
contains organic nutrients, water, and possibly other ingredients that help enrich for or select for certain types of bacteria.
May contain agar
Define Agar
similar to gelatin; provides a “solid” surface support for growth
What is cell generation time?
time for one cell to divide into two
What is the cell generation time for growth on artificial culture media?
30 to 60 minutes for most; some 15 - 30 hours.
Rapidly growing bacteria can produce millions of cells in 18 - 24 hrs
What is the colony formation time for growth on artificial culture media?
Forms colony in 15 to 48 hours for most; a few need several days or weeks
What is a colony?
a clump of a few million identical bacteria originating from the same bacterium
What are the usual characteristics of colonies?
usually 1 - 3 mm diameter; often smooth, shiny, and often with butter-like consistency
What are examples of “Atypical” bacteria?
Mycoplasma, Rickettsia, Chlamydia
What are the cell sizes of Atypical bacteria?
very small (0.1 to 0.3 um)
Are all Atypical bacteria obligate intracellular parasites?
No, only some are obligate intracellular parasites
What are the classifications of Fungi?
moulds and yeast
What is the cell type of Fungi?
eucaryotic – possesses membrane-bound nucleus and organelles, etc.
What is the cell morphology and structures of yeast?
(1) Single cell organism
(2) Oval or spherical shape
(3) Reproduce by budding new cells from existing cell or by spore formation
(4) Size: 4 to 15 um diameter
(5) Colony morphology: smooth, shiny similar to bacteria
What is the cell morphology and structures of moulds?
(1) Hyphae – multicellular long filamentous cells that branch and intertwine
(2) Reproduce by forming spores on reproductive hyphae
(3) Size: Hyphae (individual cells): 2 to 15 um diameter; up to 30 um long Spores: 1 to 10 um
(4) Mycelium (pl.=mycelia) – visible mass of hyphae (i.e. colony); may be cottony, velvety, fluffy, or leathery and in various colors
Define Hyphae
multicellular long filamentous cells that branch and intertwine
Define Mycelium
visible mass of hyphae (i.e. colony); may be cottony, velvety, fluffy, or leathery and in various colors
How does laboratory cultivation of fungi grow?
on artificial media similar to that used for bacteria; however, it usually contains antibiotics to inhibit bacteria during longer growth period
Yeast colonies usually require______ days to grow
2 to 5 days
Mould colonies usually require _______ days to grow
5 to 21 days
Explain why the virus is an obligate intracellular parasite.
a. Obligate, intracellular parasite
(1) Takes control of the host cell
(2) Requires metabolic processes of living cell to reproduce virus
What is the general size of a virus?
18 to 300 nm (0.018 to .3 um) [some up to 14,000 nm in length]
What is a virion?
a complete, fully developed, individual virus particle (Animal Viruses)
What is the composition of a capsid?
Protein
What are the functions of a capsid?
i. Contain & protect the nucleic acid
ii. Proteins serve as antigens in infection and as a site for attachment
