Lab Final Definitions – Flashcards
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| Mixed culture |
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| a microbial culture consisting of two or more species. |
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| Pure culture |
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| a microbial culture consisting of only a single species. |
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| Media |
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| Solid or liquid substances that are used for maintenance or cultivation of bacterial and fungal species. |
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| Selective Media |
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| a type of media that is designed to enhance the isolation procedure by inhibiting the growth of some organisms while encouraging the growth of other organisms. |
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| Differential Media |
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| a type of selective media that contains indicators that expose the differences between organisms. |
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| Undefined/Complex Media |
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| media that are composed of extracts from plant or animal sources and are rich in nutrients. It contains one or more ingredient made up of known ingredients, but of unknown composition, such as yeast extract, beef extract, or digest of gelatin. It supports the growth of a greater variety of microbes. |
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| Defined Media |
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| media in which the amount and identity of every ingredient is known. It supports a narrower range of organisms. |
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| Coliforms |
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| a subgroup of Enterobacteriaceae that produce gas from lactose fermentation. Most coliforms are inhabitants of the human intestinal tract and are isolated in fecal samples. Escherichia coli is the most common coliform. |
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| Nutritional Component (in selective media) |
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| = substances that are selected to obtain the optimum growth of an organism that is being tested or that is suspected of being in a sample. |
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| Inhibitors (in selective media) |
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| substances that make the media selective and are designed to exploit the weaknesses in specific groups of organisms and thus prevent or inhibit their growth, while allowing other organisms to grow. |
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| Indidcators (in selective media) |
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| substances that make a desired or expected reaction visible. The indicator is usually a dye that changes color as the pH changes. An indicator can also be a chemical that reacts with the products of a reaction to produce a color change. |
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| Family Enterobacteriaceae |
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| enteric “gut” bacteria |
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| Mixed acid fermentation |
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| is an anaerobic fermentation where the products are a complex mixture of acids, particularly lactate, acetate, succinate and formate as well as ethanol and equal amounts of hydrogen gas and carbon dioxide. |
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| 2,3-butanediol fermentation |
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| anaerobic fermentation of glucose with 2,3-butanediol as one of the end products. The other end-product is acetoin. |
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| acetoin |
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| s an end-product of glucose fermentation that is used as an external energy source by many fermentive bacteria. It is, also, a common precursor in the biosynthesis of branched chain amino acids. |
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| superoxide dismutase |
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| is an enzyme that catalyzes the conversion of superoxide radicals (O2-) to hydrogen peroxide. |
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| catalase |
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| is an enzyme that converts hydrogen peroxide to water and gaseous oxygen. |
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| cytochromes |
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| are membrane-bound hemoproteins that contain heme groups and carry out electron transport. |
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| cytochrome c |
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| is a component of the electron transport chain in mitochondria. |
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| cytochrome c oxidase |
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| is an enzyme that can oxidize cytochrome c and catalyze the reduction of cytochrome c by a chromogenic reducing agent. |
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| chromogenic reducing agent |
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| is a chemical that develops color as it becomes oxidized. |
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| nitrate reductase |
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| is an enzyme that reduces nitrate to nitrite in |
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| Denitrification |
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| is a process of nitrate reduction that may ultimately produce molecular nitrogen (N2) through a series of intermediate gaseous nitrogen oxide products. |
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| citrate-permease |
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| is an enzyme that can transport citrate molecules into the cell and enzymatically covert the molecules into pyruvate if citrate is the only carbon source available. |
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| ?-amylase (alpha) |
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| is an enzyme capable of hydrolyzing starch by breaking the glycosidic linkages between the sugar subunits. |
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| oligo-1,6-glucosidase |
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| is an enzyme capable of hydrolyzing starch by breaking the glycosidic linkages between the sugar subunits. |
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| Urease |
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| is an enzyme that can hydrolyze urea to form ammonia and carbon dioxide. |
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| Casease |
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| an enzyme capable of hydrolyzing the milk protein casein. |
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| Casein |
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| is a milk protein that gives milk its white color. |
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| Gelatinases |
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| is an extracellular enzyme that is capable of hydrolyzing gelatin. |
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| Deoxyribonuclease (DNase) |
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| is an enzyme that is capable of catalyzing the depolymerization of DNA into small fragments. |
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| Cysteine disulfurase |
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| is an enzyme that functions in the reduction of sulfur to hydrogen sulfide (H2S) by catalyzing the putrefaction of the amino acid cysteine to pyruvate. |
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| Thiosulfate deductase |
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| = is an enzyme that functions in the reduction of sulfur to hydrogen sulfide (H2S) by catalyzing the reduction of sulfur in the form of sulfate at the end of the anaerobic respiratory electron transport chain. |
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| Tryptophanase |
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| is an enzyme that can hydrolyze tryptophan to pyruvate, ammonia by deamination, and indole. |
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| Germ Theory of Disease |
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| is a theory that proposes that microorganisms are the cause of many diseases. |
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| Disinfectant |
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| is a chemical germicide that is designed for use on liquids and surfaces such as floors, tables, sinks, countertops, and surgical instruments. |
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| Antiseptic |
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| is a chemical germicide designed for use on or in living tissue. |
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| Use-Dilution Test |
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| is a standardized procedure used to measure the effectiveness of disinfectants specifically against Staphylococcus aureus, Salmonella enterica, and Pseudomonas aeruginosa |
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| Epidemiology |
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| is the study of the causes, occurrence, transmission, distribution, and prevention of diseases in a population. |
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| Morbidity |
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| sickness |
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| Mortality |
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| death |
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| Infectious Diseases |
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| are diseases caused by biological agents such as bacteria and viruses. |
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| Noninfectious diseases |
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| are diseases not caused by biological agents and include stroke, heart disease, and emphysema. |
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| Fomites |
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| contaminated objects |
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| Common Source Epidemic |
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| is when a disease is transmitted from an area that is capable of infecting many people at once. Example: an entire community sickened due to a contaminated water supply. |
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| Propagated Transmission |
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| is when a disease is transmitted from person to person. |
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| Index Case |
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| is the first case of a disease spread by propagated transmission. |
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| Hemolysins |
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| exotoxins that are able to destroy red blood cells and hemoglobin. |
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| Antibiotics |
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| are natural antimicrobial agents produced by microorganisms. |
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| antimicrobials/antimicrobics |
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| are substances that are used to treat bacterial infections. |
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| Zone of Inhibition |
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| the clear zone around an antimicrobial disk where the growth of the bacterial organism has been inhibited. |
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| Bactericidal |
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| a drug that kills bacterial organisms |
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| Bacteriostatic |
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| is a drug that can stop the growth of bacterial organisms but do not kill the organisms. |
