Labs 3- 5, 6A, 6B, 6D and Outbreaks Flashcards
Lab #3
Define culture media
Mixture of material is used to grow microbes.
What are the five basic ingredients of culture media?
Carbon, nitrogen, minerals, buffer, and water.
Complex media
A.k.a. crude ingredients. Has all 5 components necessary for growth of microorganisms, but exact amount of each unknown element is unknown.
Defined media
Chemically defined media. All ingredients needed for microorganisms growth and come with chemical formula and amount of each element is known.
Pure culture
Culture with only one species
Liquid/broth media
Liquid at room temperature and are typically contained within tubes or flasks.
Define Turbidity, Pellicle formation, and sediment
Turbidity- Cloudiness in the liquid
Pellicle formation- thin coat of cells, floating on top of broth
Sediment - deposit of cells at the tube bottom that were swirl upward if tube is tapped gently.
Solid media
The same as the broth media, except has a solidifying agent (usually agar). Liquid when hot and solid at room temperature.
Why can agar be used?
Most microorganisms do not use agar as a nutrient source.
Agar tubes (deeps)
Agar will solidify at bottom of glass culture tubes maintained in a vertical position. Used to test the ability of bacteria to catabolize nutrients under anaerobic conditions since air is not readily able to penetrate the media.
Agar slants
formed when tubes of molten, a gar containing media are placed on an angle during cooling. Tube contents hardens with the slanted or slope surface that can be easily in oculated. Commonly used to maintain stock cultures because they provide a broad surface for growth and observation, but do not dry out as fast as agar plates.
Agar plates
Molten agar media poured into patriot plates. Will cool to form broad, thin slabs of solid media. Allows for mixtures of different bacteria types to be inoculated in colonies of individual types to be easily separated from one another for isolation and identification.
Pseudomonas
Use sodium benzoate eight as a carbon source.
Azotobacter
Nitrogen fixing bacteria. These organisms can use and two from the atmosphere as their source of nitrogen so no source of nitrogen is included in their medium.
Lab #4
Streak plate method
A successful, executed streak plate will yield well spaced, isolated colonies from the same species. The main objective of this technique is to dilute the culture to produce while isolated colonies.
Aseptic technique
Be able to inoculate media with desired pure cultures without introducing any other organisms.
Inoculation loop
Two used to transfer bacteria from cultures grown on solid media. Use a small volume of cells for routine inoculations.
Petri plates are always incubated agar side-down
False
How should plates be labeled?
First initial, last name in full, identity of culture used, current date, and type of medium used.
Lab #5
Define colony
Mass of cells visible to the naked eye, and represents a clone of cells arising from a single vegetative cell, a spore, or a number of cells connected together in a chain or cluster.
Define morphology
Defined as the science or study of form, or external appearance, without regard to function (size, shape, color, etc.)
Another name for morphological features
Cultural characteristics
Form
Shape of whole colonies, growing on agar surface.
Punctiform (less than 1mm in diameter), Circular, irregular, filamentous (fuzzy), and rhizoid (root-like).
Margin
The edge of an individual colony.
Described as entire (smooth edge), undulate (wavy), lobate (cloud), serrate (serrated butter knife), filamentous (fuzzy/tree like), curled (rings).
Elevation
Flat, raised, convex, pulvinate (dome-shaped), umbonate (lump in center) or referred to with indentation/crater in center but some refer that as crateriform.
Surface texture
Always describe using two terms. One to describe the smoothness of the surface (ex. Smooth, rough, or wrinkled.) the other term would be used to describe the sheen of the surface (shiny, glistening, door, dry, or powdery.)
Optical character
Described as either opaque or translucent. Place over page with paper with print. If the print can be seen through the isolated colony, it is translucent. If not see through, it is opaque. Some will be fluorescent (glow when exposed to ultraviolet light) or bioluminescent (produce their own light.)
Lab 6A
Direct staining
Cells are colored, but leaves background colorless.
Indirect staining/negative staining
Colors the background, but leaves the cells uncolored.
Basic stain
Color associated with positive ion (cation). Used in direct standings. Ex. Methylene, blue, crystal violet, and safranin.
Acidic stain
Color associated with negative ion (anion). Used an indirect staining. Ex Congo red
What is the advantage of indirect staining over direct standing?
It causes less cellular distortion, so cells retain their actual size and shape.
Define smear
A mixture of liquid (usually water) and micro organisms on the surface of a glass slide, and is most useful if thin and uniform in consistency. Less is more.
Defined the procedure of Heat fixing
Involves passing a slide containing back to your cell through a flame. This reduces potential hazard of handling slide containing pathogenic microorganisms.
Define the procedure of wet mount
used to determine motility of an organism (running and tumbling). The presence of bacterial flagella can be inferred by observing living bacteria under the microscope while they are fresh (24-48 hours) bacteria demonstrate running in tumbling movement if they are considered motile which infers they have flagella.
Lab 6D
Special stains/structural stains
Direct staining techniques that include endospore capsule and flagellar stains. Allow for differentiation of specific back to your structures found either inside or outside of cells.
Bacterial endospores
Dormant structures produced by a variety of bacterial species, which are highly resistant to heat, desiccation, and toxic chemicals. Resistant to staining, but one stand are highly resistant to being decolorized. Older cells will often degenerate, leaving their spores now called exospores behind in the environment.
Define sporangium
Spore containing cell. Can only contain one cell at a time.
Malachite green
Primary stain in endospore stain. Direct stain to cells and colors the cells and endospores green (if any).
Outbreak!
Bactria that causes Pneumococcal pneumonia?
Streptococcus pneumoniae
Outbreak!
Bacteria that causes MRSA?
Staphylococcus aureus
Outbreak!
Bacteria that causes Tuberculosis?
Mycobacterium tuberculosis
Outbreak!
Bacteria that causes Dental caries
Streptococcus mutans
