Term
| what are the 5 I's of culturing microbes |
|
Definition
Inoculation – introduction of a sample into a container of media to produce a culture of observable growth
Isolation – separating one species from another
Incubation – under conditions that allow growth
Inspection
Identification |
|
|
Term
|
Definition
| If an individual bacterial cell is separated from other cells and has space on a nutrient surface, it will grow into a mound of cells. |
|
|
Term
| how many species does a colony consist of |
|
Definition
|
|
Term
| what do isolation techniques include |
|
Definition
Streak plate technique
Pour plate technique
Spread plate technique |
|
|
Term
| Media can be classified according to what three properties. Describe them. |
|
Definition
Physical state – liquid, semisolid, and solid
Chemical composition – synthetic (chemically defined) and nonsynthetic (complex)
Functional type – general purpose, enriched, selective, differential, anaerobic, transport, assay, enumeration |
|
|
Term
|
Definition
Liquid – broth; does not solidify
Semisolid – contains solidifying agent
Solid – firm surface for colony formation:Contains solidifying agent and can be either Liquefiable or nonliquefiable |
|
|
Term
| name and describe the most commonly used media |
|
Definition
Nutrient broth – liquid medium containing beef extract and peptone
Nutrient agar – solid media containing beef extract, peptone, and agar |
|
|
Term
| Most commonly used solidifying agent is what? Describe it. |
|
Definition
agar:
A complex polysaccharide isolated from red algae
Solid at room temperature, liquefies at boiling (100oC), does not re-solidify until it cools to 42oC
Provides framework to hold moisture and nutrients
Not digestible for most microbes |
|
|
Term
|
Definition
| contains pure organic and inorganic compounds in an exact chemical formula |
|
|
Term
|
Definition
| contains at least one ingredient that is not chemically definable |
|
|
Term
|
Definition
| grows a broad range of microbes, usually nonsynthetic |
|
|
Term
|
Definition
| contains complex organic substances such as blood, serum, hemoglobin, or special growth factors required by fastidious microbes |
|
|
Term
|
Definition
| contains one or more agents that inhibit growth of some microbes and encourage growth of the desired microbes |
|
|
Term
|
Definition
| allows growth of several types of microbes and displays visible differences among those microbes |
|
|
Term
|
Definition
| contains a substance that absorbs oxygen or slows penetration of oxygen into medium; used for growing anaerobic bacteria |
|
|
Term
| Carbohydrate fermentation medium |
|
Definition
| contains sugars that can be fermented, converted to acids, and a pH indicator to show this reaction |
|
|
Term
|
Definition
temperature-controlled chamber
Microbe multiplies and produces macroscopically observable growth |
|
|
Term
|
Definition
observation; macroscopic and microscopic of:
Pure culture – grows only single known species of microorganisms
Mixed cultures – hold two or more identified species or microorganisms
Contaminated culture – once pure or mixed culture that has unwanted microbes growing |
|
|
Term
|
Definition
| macroscopic and microscopic appearance, biochemical tests, genetic characteristics, immunological testing |
|
|
Term
| How to dispose of cultures |
|
Definition
Potentially hazardous cultures and specimens are usually disposed of in two ways:
Steam sterilization
Incineration |
|
|
Term
| what are the key characteristics of a reliable microscope |
|
Definition
Magnification – ability to enlarge objects
Resolving power – ability to show detail |
|
|
Term
| How does magnification of most microscopes happen |
|
Definition
| from interaction between visible light waves and curvature of the lens |
|
|
Term
|
Definition
| Angle of light passing through convex surface of glass changes |
|
|
Term
|
Definition
|
|
Term
| what 2 phases does magnification occur in |
|
Definition
The objective lens forms the magnified real image
The real image is projected to the ocular where it is magnified again to form the virtual image |
|
|
Term
| what is total magnification |
|
Definition
a product of the separate magnifying powers of the two lenses
power of objective x power of ocular = total magnification |
|
|
Term
|
Definition
| Resolution defines the capacity to distinguish or separate two adjacent objects |
|
|
Term
| variations on the optical microscope |
|
Definition
Bright-field – most widely used; specimen is darker than surrounding field; live and preserved stained specimens
Dark-field – brightly illuminated specimens surrounded by dark field; live and unstained specimens
Phase-contrast – transforms subtle changes in light waves passing through the specimen into differences in light intensity, best for observing intracellular structures |
|
|
Term
|
Definition
Modified compound microscope with an ultraviolet radiation source and filter that protects the viewer’s eye
Uses dyes that emit visible light when bombarded with shorter UV rays - fluorescence
Useful in diagnosing infections |
|
|
Term
| how does an electron microscope form an image |
|
Definition
| with a beam of electrons that can be made to travel in wavelike patterns when accelerated to high speeds |
|
|
Term
| name and describe the 2 types of electron microscopes |
|
Definition
Transmission electron microscopes (TEM) – transmit electrons through the specimen. Darker areas represent thicker, denser parts and lighter areas indicate more transparent, less dense parts.
Scanning electron microscopes (SEM) – provide detailed three-dimensional view. SEM bombards surface of a whole, metal-coated specimen with electrons while scanning back and forth over it. |
|
|
Term
| what does Preparation of slide depend on |
|
Definition
Condition of specimen
Aims of examiner
Type of microscopy available |
|
|
Term
| Wet mounts and hanging drop mounts |
|
Definition
| allow examination of characteristics of live cells: size, motility, shape, and arrangement |
|
|
Term
|
Definition
| are made by drying and heating a film of specimen. This smear is stained using dyes to permit visualization of cells or cell parts |
|
|
Term
| how do dyes create contrast |
|
Definition
| by imparting a color to cells or cell parts |
|
|
Term
|
Definition
| cationic, positively charged chromophore |
|
|
Term
|
Definition
| anionic, negatively charged chromophore |
|
|
Term
|
Definition
| surfaces of microbes are negatively charged and attract basic dyes |
|
|
Term
|
Definition
| microbe repels dye, the dye stains the background |
|
|
Term
|
Definition
| one dye is used; reveals shape, size, and arrangement |
|
|
Term
|
Definition
| use a primary stain and a counterstain to distinguish cell types or parts (examples: Gram stain, acid-fast stain, and endospore stain) |
|
|
Term
|
Definition
| reveal certain cell parts not revealed by conventional methods: capsule and flagellar stains |
|
|
