Lab Exam 1 Flashcards
Colony
A visible population of microorganisms growing on a solid medium
Agar
A carbohydrate derived from seaweed used to solidify a liquid medium.
Inoculate
To transfer organisms to a medium to initiate growth
Media
The substance used to support the growth if microorganisms
Normal biota
(Normal flora)
The organisms usually found associated with parts of the body.
Pathogen
An organism capable of causing disease.
Ubiquity
The existence of something everywhere at the same time
Aseptic
Free of contamination
Incubate
Store cultures under conditions suitable for growth, often in an incubator.
Pure culture
A population of cells resulting from the growth of a single cell.
Sterile
Free of viable bacteria or viruses
Streak plate
A technique for isolating pure cultures by spreading organisms on an agar plate.
Compound microscope
A microscope with more than one lens system
Condenser
A structure located below the stage that contains a lens for focusing light on the specimens as well as an iris diaphragm.
Iris diaphragm
An adjustable opening that regulated the amount of light illuminating the specimen.
Magnification
The microscopes ability to optically increase the size of a specimen
Resolution
The smallest separation that two structural forms must have in order to be distinguished optically as separate.
Ex. 2 adjacent cilia
Wet mount
A laboratory technique in which a microscopic specimen in liquid is placed on the surface of a slide and covered with a coverslip.
Immersion Oil
Oil placed on a slide to minimize refraction of the light entering the lens.
Refraction
The bending or light as is passes from one medium to another.
Refractive index
The ratio of the velocity of light in the first two media to its velocity in the second medium as it passes from one medium into another medium.
Capsule
A gelatinous material coating the outside of a cell.
Differential stain
- A procedure that stains a specific morphological structure
- Typically a multiple stain
Ex. Gram stain & acid fast stain
Inclusion bodies
Granules of storage material such as sulfur that accumulate within some bacterial cells.
Micrometer (um)
The metric unit to measure bacteria.
1 meter = 1,000,000 micrometers
1 mm = 1,000 micrometers
Negative stain
A simple stain in which the organisms appear clear against a dark background
Parfocal
All the objective lenses of the microscope are in the same plane, so you don’t have to refocus when changing lenses.
Simple stain
A procedure for staining bacteria consisting of a single stain
Smear
A dried mixture of bacteria and water (or broth) placed on a glass slide for preparation for staining
Counter stain
- A stain used to dye unstained cells
- contrasting color is differential stain
Mordant
A substance that increases the adherence of a dye
Peptidoglycan
The macromolecule making up the cell wall of most bacteria
Vegetative cell
A cell that has not formed spores or other resting stages
Peritrichous
The surface of the organism is covered with flagella, such as E. Coli
Polar
A single flagellum at one or both ends of the organism
Ex. Pseudomonas
Polar tuft (lophotrichous)
A tuft of flagella at one or each ends of the organism
Ex. Spirillum
Chemically defined medium
A synthetic medium composed of inorganic salts and usually a carbon source such as glucose
Complex medium
(Undefined medium)
- The exact amounts of chemical components and their composition are unknown.
- not measured
Differential medium
Permits certain organisms to be distinguished from others by the appearance of their colonies.
Enteric
Associated with the intestine
Fastidious
Require growth factor
Ex. Staphylococcus
Glucose mineral medium
A chemically defined medium containing glucose as a carbon source and salts (NH4Cl , KH2PO4) for a nitrogen and phosphate source
Growth factor
A compound such as a vitamin or amino acid that is required by an organism to grow
Rich (enriched) medium
- A medium, usually complex, containing many growth factors.
- sometimes blood or additional vitamins are added to permit the growth or organisms with special requirements.
Selective medium
Medium formulated to permit the growth of certain bacteria, but not others.
