Microbiology/Tortora Ch. 6 – Flashcards
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| Psychrotrophs |
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| Spoilage microorganisms |
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| Hyperthermophiles |
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| Extreme thermophiles, most live in hot springs associated w/ volcanic activity |
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| Acidophiles |
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| Tolerate acidity |
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| plasmolysis |
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| Shrinkage of cell's cytoplasm |
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| Extreme halophiles |
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| Tolerate/ require high concentrations of salt |
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| Obligate halophiles |
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| Require salt |
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| Falcultative |
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| Able to grow in salt concentrations up to 2% |
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| Nitrogen fixatin |
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| bacteria that use gaseous nitrogen directly from the atmosphere |
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| Obligate aerobes |
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| Organisms that require oxygen to live |
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| Facultative anaerobes |
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| Aerobic bacteria that can continue to grow without oxygen |
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| Obligate anaerobes |
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| Can't use oxygen for energy |
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| Singlet oxygen |
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| Normal molecular oxygen boosted to higher energy state & is extremely reactive |
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| Superoxide radicals (or superoxide anions) |
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| Formed during respiration as a final electron acceptor |
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| Superoxide dismutase |
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| Enzyme produced by organisms attempting to grow in atmospheric oxygen |
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| Peroxide anion |
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| Peroxide produced when superoxide radical converts into molecular oxygen and hydrogen peroxide |
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| Catalase |
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| Occurs when peroxide is added to a colony of bacteria (oxygen bubbles released) |
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| Peroxidase |
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| Differs from catalase in that its reaction does not produce oxygen |
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| Hydroxyl Radical |
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| Intermediate form of oxygen & probably the most reactive |
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| Aerotolerent Anaerobes |
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| Cannot use oxygen for growth, but tolerates it fairly well |
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| Microaerophiles |
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| Do not require oxygen |
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| Organic Growth Factors |
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| Essential organic compunds that an organism is unable to synthesize |
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| Biofilm |
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| Slime |
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| Culture Medium |
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| Nutrient material prepared for growth of microorganisms in a lab |
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| Inoculum |
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| Microbes introduced to culture medium to initiate growth |
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| Culture |
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| Microbes that grow & multiply in or on a culture medium |
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| Sterile |
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| Contains no living microorganisms |
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| Agar |
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| Complex polysaccharide derived from a marine alga |
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| Chemical Defined Medium |
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| One whose exact chemical composition is known |
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| Complex Media |
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| Made up of nutrients including extracts from yeasts, meat,or plants or digests of proteins from these & other sources |
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| Nutrient Broth |
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| Complex medium in liquid form |
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| Reducing Media |
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| contain ingrediants that chemically combine with dissolved oxygen & deplete oxygen in the culture medium |
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| Capnophiles |
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| Microbes that grow better @ high CO2 concentrations |
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| Selective Media |
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| Encourage growth of desired microbes |
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| Differential Media |
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| Make it easier to distinguish colonies of desired organism from other colonies growing on the same plate |
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| Enrichment Culture |
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| Usually a liquid & it provides nutrients & environmental conditions that favor growth of particular microbe, but not others |
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| Colony |
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| Arises from single spore or cell & form clumps or chains |
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| Streak Plate Method |
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| Loop dipped in culture & streaked in pattern over surface of nutrient meduim |
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| Deep Freezing |
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| Microbes placed in suspending liquid & quick frozen at -50 to -90 degrees C |
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| Lyphilization |
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| Freeze-drying, quickly frozen & water removed |
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| Binary Fission |
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| Increase in numbers, not size |
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| Budding |
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| Grows a bud, enlarges to nearly size of parent cell, then separates |
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| Generation Time |
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| Time required for cell to divide & population to double |
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| Bacterial Growth Curve |
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| Shows growth of cells over time |
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| Lag Phase |
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| No cell division |
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| Log Phase |
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| (aka exponential growth phase) Most active period |
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| Stationary Phase |
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| period of equilibrium |
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| Death Phase |
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| (aka log decline phase) # of deaths exceed # of new cells formed |
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| Plate Count |
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| Method of measuring bacterial populations |
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| Colony-Forming Units |
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| What plate counts are reported as |
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| Serial Dilution |
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| Original inoculum is diluted several times |
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| Spread Plate Method |
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| 0.1ml inoculum added to surgace of prepared algar, inoculum is spread with a sterilized rod |
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| Filtration |
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| Technique to count bacteria |
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| Most Probable Number Method |
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| Statistical estimating technique based on the fact that the greater the # of bacterial in a sample, the more dilution is needed to produce density to point @ which no bacteria are left to grow in tubes in a dilution series |
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| Direct Microscopic Count |
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| measures bacterial suspension in defined area |
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| Turbidity |
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| Monitoring growth, bacteria multiply in liquid and make it cloudy (or "turbid") |
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| Psychrophiles |
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| Cold-loving |
