An individual bacterial cell that is seperated from other cells will produce a colony consisting of only one species if provided adequate space on a nutrient surface. What type of technique is based on this concept?
Process in which microbes are cultivated, or cultured. The inoculum (tiny sample) is introduced into a container of nutrients (medium) so they can multiply.
Obervable growth happens after this I.
What is needed for the proper isolation of a bacteria?
Isolation technique of choice due to its ease and effectiveness.
What isolation technique involves a small volume of liquid, diluted sample that is pipetted around evenly by a sterile spreading tool.
Isolation technique where a sample is inoculated serially in liquid agar tubes so as to dilute the number of cells in each successive tube in the series. Tubes are poured into petris and allowed to harden. Colonies may develop deep in the medium.
loop dilution, also called pour plate
How many different types of media are used in culturing and identifying microorganisms?
at least 500
These, along with certain bacteria, cannot grow on artificial media.
Media can be classified according to what three properties?
Liquid media ( broths, milks, or infusions ) are made by dissolving solutes in this
This type of media exhibits a clotlike consistency at room temp. Used to determine the motility of bacteria and to localize a reaction at a specific site. Media is stabbed in center and later observedfor pattern growth
Media that is either liquefiable or non. Used in isolating and culturing bacteria and fungi.
Agar is a complex polysaccharide isolated from this.
Gelidium- a red algae
T/F? Agar is a flexible and moldable nutrient for most microorganisms.
False. Not digestible for most microorganisms.
Agar is solid at room temp and melts at what temp?
At what temp does agar resolidify?
Temp range that agar can be inoculated and poured in liquid form.
45 - 50 C
Media whose compositions are precisely chemically defined. Contain pure organic and inorganic compounds and have a molecular content specified by means of an exact formula. Most useful in research and cell culture when the exact nutritional needs of the test organisms are known.
Media that contains at least one ingredient that is not chemically definable, i.e. ground up cells, tissue, and secretions from animals, plants, or yeasts. Blood, serum, and meat extracts or infusions. Milk, yeast extract, soybean digests, and peptone (partially degraded protein used as a C and N source).
complex or nonsynthetic
What are three types of general-purpose media (used for growing a broad spectrum of microbes)? Non -synthetic.
nutrient agar and broth
trypticase soy agar (TSA) - contains partially degraded milk protein (casein), soybean digest, NaCl, agar
An enriched medium contains complex organic substances like blood, serum, hemoglobin, or special growth factors (specific vitamins, amino acids), what is the term used to describe microbes that require this type of media?
What are the two types of media that are designed for special microbial groups that have extensive applications in isolation and identification.
T/F? Selective media is selective of the microbes it allows to grow, hastening isolation.
Gram-positive or -negative? Inhibited by bile salts (component of feces), dyes such as methylene blue and crystal violet.
Media that allows multiple types of microorganisms to grow but are designed to display visible differences among the organisms. Shows variations in colony size or color, media color changes, or the formation of gas bubbles
T/F? A single medium can be both selective and differential.
MacConkey agar will turn from yellow to this color when acidic.
red or pink
A reducing medium contains a substance that absorbs or slows the penetration of this.
T/F? Carbohydrate fermentation media contain sugars that can be fermented (converted to bases) and a pH indicator to show the reaction.
False. Fermentation converts sugars to acids.
To prevent cell destruction by enzymes, pH changes, and toxic substances, transport media contain these (3).
enzymes - salt
pH - buffers
toxins - absorbants
Media used to test the effectiveness of antimicrobial drugs, disinfectants, antiseptics, cosmetics, and preservatives.
T/F? Enumeration media is used to count the number of organisms in milk, water, food, soil...
When a culture is free of other living things except for the one being studied, it is described as axenic or this type of culture
T/F? Mixed cultures hold two or more identified, easily differentiated species.