Microbial Growth Test Questions – Flashcards
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| Buffer |
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| Used in media to neutralize acids |
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| Psychrophile |
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The general term for organisms capable of growth at 0°C |
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| Thermophile |
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Capable of growth at high temperatures; optimum 50-60°C |
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| Extreme Halophile |
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| Adapted to high salt concentrations, which are required for growth |
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| Plasmolysis |
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| A phenomenon that occurs when bacteria are placed in high salt concentrations |
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| Psychrotrophs |
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| Term used in text for organisms that grow well at refrigerator temperatures; optimum growth is at temperatures of 20-30°C |
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| Capnophile |
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| Microbes that grow better at high CO2 |
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| Hyperthermophile |
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| Members of the archaea with an optimum growth temperature of 80°C or higher |
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| Hydrogel |
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| The matrix that makes up a biofilm |
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| Catalase |
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| An enzyme acting upon hydrogen peroxide |
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| Nitrogen Fixation |
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| Rhizobium bacteria do this in symbiosis with leguminous plants |
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| Obligate Aerobe |
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| Requires atmospheric oxygen to grow |
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| Microaerophile |
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| Requires atmospheric oxygen, but in lower than normal concentrations |
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| Aerotolerant anaerobe |
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| Does not use oxygen, but grows readily in its presence |
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| Obligate Anaerobe |
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| Does not use oxygen and usually finds it toxic |
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| Peptones |
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| Important source of energy, carbon, nitrogen, and sulfur requirements in complex media |
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| Peroxidase |
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| Breaks down hydrogen peroxide without generation of oxygen |
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| Hydroxyl Radical |
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| Formed in cytoplasm by ionizing radiation |
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| Catalase |
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| An enzyme that converts hydrogen peroxide into oxygen and water |
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| Superoxide radicals |
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| The toxic form of oxygen that is neutralized by superoxide dismutase - synonym for superoxide anions |
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| Oxyrase |
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| A component added to some culture media that makes the Petri plate into a self-contained anaerobic chamber |
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| Streak Plate |
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| Isolation method for getting pure cultures; uses an inoculating loop to trace a pattern of inoculum on a solid medium |
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| Spread Plate |
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| Colonies grow on agar surface for identification |
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| Differential Medium |
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| Used to increase the numbers of a small minority of microorganisms in a mixed culture to arrive at a detectable level of microorganisms |
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| Lyophilization |
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| Preservation method that uses quick-freezing and a high vacuum |
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| Colonies |
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| Accumulations of microbes large enough to see without a microscope |
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| Inoculum |
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| Microbes added to initiate growth |
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| BSL-3 |
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| Usual laboratory designation for safe handling of tuberculosis |
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| BSL-4 |
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| Laboratory designation for the most dangerous microorganisms; personnel wear "space suits" |
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| BSL-1 |
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| A routine microbiology teaching laboratory would be designated this |
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| Stationary phase |
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| New cell numbers balanced by death of cells |
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| Lag Phase |
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| No cell division, but intense metabolic activity |
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| Log Phase |
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| A logarithmic plot of the population produces an ascending straight line |
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| Reducing Media |
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| Used to grow obligate anaerobes; generally contain ingredients such as sodium thioglycolate that chemically combine with dissolved oxygen |
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| Selective Media |
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| Designed to suppress the growth of unwanted bacteria and to encourage growth of desired microbes |
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| Complex Media |
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| Nutrients are digests or extracts; exact chemical composition varies slightly from batch to batch |
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| Polysaccharide |
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| Agar is a derived from a marine alga. |
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| cyanobacteria |
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A few bacteria and the photosynthesizing are able to use gaseous nitrogen directly from the atmosphere |
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| Mesophiles |
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| The most common microbes; their optimum growth temperatures are 25-40°C |
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| Nutrient broth |
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| A complex medium in liquid form |
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| Absorbance (OD) |
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| How turbidity is usually recorded in a spectrophotometer |
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| Dry weight measurement |
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| How the growth of filamentous bacteria is usually recorded |
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| Facultative anaerobes |
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| Grow more efficiently aerobically than they do anaerobically |
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| Facultative halophiles |
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| do not require high salt concentrations, but they are able to grow at salt concentrations that may inhibit the growth of many other bacteria. |
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| Phsophate salts, amino acids, and peptones |
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| are examples of buffers found in complex media |
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| Culture Medium |
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| Any nutrient material prepared fro the growth of bacteria in a laboratory |
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| Agar |
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| melts at about the boiling point of water but remains liquid until the temperature drops to about 40°C |
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| Pour plate method |
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Dilutions of a bacterial mixture are poured into a Petri dish and mixed with melted agar; this is a plate counting method. |
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| Peptones |
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| Partially digested protein products that are used in complex media |
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| Living host cells |
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| Usually necessary to grow obligate intracellular parasites such as rickettsias and chlamydias |
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| Reduction |
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| The general term for tests that estimate microbial growth by the time required for them to deplete oxygen in the medium is tests. |
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| Colony-forming Unit |
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| When a single colony arises from a clump a bacteria, it is recorded as a(n) . |
