Term
| what are the two main critieria for classifying organisms based on nutrients |
|
Definition
| source of carbon and source of energy |
|
|
Term
| two groups based on source of carbon |
|
Definition
| autotrophs and heterotrophs |
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Term
|
Definition
| utilize an inorganic source of carbon (CO2) "self feeders" |
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Term
|
Definition
| catabolize reduced organic molecules that they aquire from other organisms |
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Term
| groups based on source of energy |
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Definition
| phototrophs and chemotrophs |
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Term
|
Definition
| organisms that aquire energy from redox reactions involoving inorganic and organic chemicals |
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Term
|
Definition
| use light as their energy source |
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|
Term
| most organisms can be categorized into these four main groups |
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Definition
| photoautotrophs, photoheterotrophs, chemoautotrophs, and chemoheterotrophs |
|
|
Term
| the cells of all organisms require (blank) and (blank) for redox reactions |
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Definition
| electrons and hydrogen atoms |
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|
Term
| what element is never the limiting nutrient |
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Definition
|
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Term
|
Definition
| organisms that aquire nutrients from the same organic molecules that provide them with carbon and energy |
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Term
|
Definition
| organisms that acquire electrons and hydrogen from inorganic sources |
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Term
|
Definition
| require oxygen to survive |
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Term
|
Definition
| because oxygen serves as the final electron acceptor |
|
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Term
|
Definition
| they steal electrons from other compounds with in turn steal electrons from other compounds causing irreperable damage to cells by oxidzing important compounds like proteins and lipids |
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Term
|
Definition
| electrons have been boosted to a higher state |
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|
Term
| what pigement prevents toxicity by removing the excess energy of the singlet oxygen |
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Definition
|
|
Term
| what organisms usually carry carotenoids |
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Definition
|
|
Term
| superoxidative radical form during |
|
Definition
| the incomplete reduction of O2 |
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|
Term
| superoxidative radicals are so reactive that aerobic organisms must produce enzymes called |
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Definition
|
|
Term
| how does superoxide dismutase work |
|
Definition
| they have active sites that contain metal ions which combine two superoxide radicals with two protons to form hydrogen peroxide and molecular oxygen |
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Term
|
Definition
| hydrogen peroxide formed during reactions catalyzed by superoxide dismutase contains peroxide anion |
|
|
Term
| what enzymes detoxify peroxide anion |
|
Definition
|
|
Term
| catalase converts hydrogen peroxide to |
|
Definition
| water and molecular oxygen |
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|
Term
| the production of bubbles with the addition of hydrogen peroxide indicates |
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Definition
|
|
Term
| peroxidase breaks down hydrogen peroxide without forming |
|
Definition
| oxygen, using a reducing agent such as NADH |
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|
Term
| hydroxyl radical result from |
|
Definition
| ionizing radiation and from an incomplete reduction of hydrogen peroxide |
|
|
Term
| what are the four toxic forms of oxygen |
|
Definition
| singlet oxygen, superoxide radical, peroxide anion, and hydroxyl radical |
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|
Term
| of the four, which is the most reactive |
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Definition
|
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Term
|
Definition
|
|
Term
|
Definition
| oxygen is a deadly poison for these organisms |
|
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Term
|
Definition
| can maintain life via fermentation or anaerobic respiration, but their efficiency is often reduced in the absence of oxygen |
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Term
|
Definition
| do not use aerobic pathways but they tolerate oxygen by having some of the enzymes to detoxify oxygens poisonous forms |
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Term
|
Definition
| require oxygen levels of between 2 and 10 percent (this concentration is found in the stomach) |
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|
Term
| what is an element that is often a limiting nutrient |
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Definition
|
|
Term
| trace elements are so named because we need them is |
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Definition
|
|
Term
|
Definition
| certain organic chemicals that are needed by organisms in small amounts, but they cannon synthesize |
|
|
Term
| physical requirements for growth |
|
Definition
| temperature, pH, osmolarity and pressure |
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|
Term
| minimum growth temperature |
|
Definition
| the lowest temp at which an organism is able to conduct metabolism |
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Term
|
Definition
| the highest temp at which an organism is able to metabolise |
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Term
|
Definition
| the temp at which an organisms metabolic activities produce the highest growth rate |
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Term
|
Definition
| thrive at low temperature |
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Term
|
Definition
| organisms that thrive at room temperature |
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Term
|
Definition
|
|
Term
|
Definition
| live at extremely hot temps |
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|
Term
| how does pH effect organisms |
|
Definition
| hydrogen ions and hydroxyl ions interfere with hydrogen bonding within the molecules of proteins and nucleic acids |
|
|
Term
| most bacteria and protzoa grow at what type of pH |
|
Definition
|
|
Term
| organisms that thrive in neutral pH are called |
|
Definition
|
|
Term
|
Definition
| thrive at low pH values (acidic) |
|
|
Term
|
Definition
| high pH values (basic conditions) |
|
|
Term
| what do all microorganisms require to live |
|
Definition
|
|
Term
|
Definition
| adapted to grow under high osmotic pressure (salty conditions) |
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Term
|
Definition
| organisms that live under extreme pressures |
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|
Term
| can barophiles live in area with low hydrostatic pressure |
|
Definition
| no, their cell membranes and enzymes depend on high pressures to maintain their three dimensional shapes |
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Term
|
Definition
| complex relationships between numerous individuals, which are often of a different species |
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|
Term
| biofilms often form as a result of |
|
Definition
| quorum sensing, in which bacteria respond to the desity of near by bacteria |
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Term
|
Definition
| a sample that is introduced to a medium |
|
|
Term
|
Definition
| a collection of nutrients |
|
|
Term
| microorganisms that grow on a medium are called a |
|
Definition
|
|
Term
|
Definition
| the act of cultivating microorganisms or the mircroorganisms that have been cultivated |
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|
Term
| liquid mediums are called |
|
Definition
|
|
Term
|
Definition
| a sample of human material that is examined or tested for the presence of microorganisms |
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|
Term
|
Definition
| cultures composed of cells arising from a single progenitor |
|
|
Term
|
Definition
| colony forming unit (the progenitor) |
|
|
Term
| the most commonly used isolation technique is the |
|
Definition
|
|
Term
| in the pour plate technique, CFU's are seperated from one another using |
|
Definition
|
|
Term
| during the pour plate method, the more diluted media is mixed in petri dishes with |
|
Definition
| sterile, warm medium containig agar |
|
|
Term
| the difference between a petri dish using the streak plate method and the pour plate method is that |
|
Definition
| the one using the pour plate method has microorganisms throughout, not just on the surface |
|
|
Term
| isolation techiniques work well only if |
|
Definition
| a relatively large number of CFU's of the organism of interest are present in the initial sample and if the medium supports the growth |
|
|
Term
|
Definition
| powdered beef extract and peptones dissolved in water |
|
|
Term
| what are four reasons agar is so widely used |
|
Definition
| most microorganisms cannot digest agar, agar dissolves at 100 degrees C, it solidifies at below 40 degrees C, and it does not melt below 100 degree C |
|
|
Term
| what is the medium called when the medium is allowed to cool on a slant? what about straigh up? |
|
Definition
|
|
Term
|
Definition
| one in which the exact chemical makeup is known |
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|
Term
| defined medium is also called |
|
Definition
|
|
Term
| organisms that require a relativly large number of growth factors are called |
|
Definition
|
|
Term
|
Definition
| contain nutrients released by the partial digestion of yeast, beef, soy or proteins (exact composition is not known) |
|
|
Term
| what kind of organisms are usually grown on complex media |
|
Definition
|
|
Term
| what are two up sides to complex media |
|
Definition
| it can support a variety of different microorganisms and it can be used to culture an organism whose exact nutritional needs are not known |
|
|
Term
|
Definition
| either the presence of visible changes in the medium or differences in the appearances of colonies helps microbiologist differentiate amoung different kinds of bacteria |
|
|
Term
| what does it mean when a medium is both selective and differential |
|
Definition
| they enhannce the growth of a certain species that can be distinguished from the other species by variations in their effect on the medium |
|
|
Term
| what kind of medium would you use to grow anaerobic organisms |
|
Definition
|
|
Term
|
Definition
| contains compounds that chemically combine with free oxygen and remove it from the medium |
|
|
Term
| what is a technique that can be used to culture anaerobic microorganism |
|
Definition
| stab technique (use an inoculating needle and stab it into the oxygen free depths of the medium) |
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|
Term
|
Definition
| used when speed and not contaminating a specimen is needed |
|
|
Term
| what can be used for organisms in which artificial media is inadequate |
|
Definition
|
|
Term
| how to culture organisms that require an environment somewhere between aerobic and anaerobic |
|
Definition
| carbon dioxide incubators (machines that electronically monitor and control carbon dioxide levels which mimic the environment in the intestinal tract) |
|
|
Term
|
Definition
| organisms that grow best with a relatively high concentration of carbon dioxide (3 to 10 percent) |
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|
Term
|
Definition
| cultures designed to increase very small numbers of chosen microbe to obserable levels |
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|
Term
|
Definition
| another type of enrichment used on organisms that thrive in cold environments |
|
|
Term
| what is the best technique for storing bacterial cultures for a short period of time |
|
Definition
|
|
Term
| which methods keeps cultures stored for years |
|
Definition
|
|
Term
| what method is best for keeping cultures for the longest period of time |
|
Definition
|
|
Term
|
Definition
| involves removing water from a frozen culture using a vacuum (freeze drying) |
|
|
Term
|
Definition
| cell grows to twice its normal size, then splits into two daughter cells |
|
|
Term
| logarithmic (or exponential) growth |
|
Definition
| when something doubles at each interval |
|
|
Term
| how is the growth of number of cells calculated |
|
Definition
| two to the n where n is the number of generations |
|
|
Term
|
Definition
| the amount of time required for a bacterial cell to grow and divide |
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|
Term
|
Definition
| a graph that plots the numbers of organisms in a growing population over time |
|
|
Term
| what are two problems when using exponential growth curves |
|
Definition
| it is difficult or impossible to distinguish numbers in early genreations, and as the pop grows it becomes hard to keep the graph on one sheet of paper |
|
|
Term
| what is the solution to these problems |
|
Definition
| to replace the arithmetic scale with a logarithmic scale on the y axis |
|
|
Term
| on a log scale each division is |
|
Definition
|
|
Term
| what are the four distinct phases to a populations growth curve |
|
Definition
| lag, log, stationary and death |
|
|
Term
|
Definition
| cells adusting to new environment (instead of reproducing, they are synthesizing enzymes to utilize the nutrients that are in the medium) |
|
|
Term
|
Definition
| rapid chromosome replication, growth and reproduction |
|
|
Term
| what is one reason researchers are interested in bacteria in their log phase |
|
Definition
| because that is when they are more suseptable to antimicrobial drugs |
|
|
Term
|
Definition
| the number of dying cells equals the number of cells being produced and the size of the population becomes stationary |
|
|
Term
| the onset of the stationary phase can be postponed indefinitely by the use of a special apparatus called a |
|
Definition
| chemostat, which continuously removes wastes and adds fresh medium |
|
|
Term
|
Definition
| the point at which the cells are dying faster than they are being produced (some species create endospores at this phase) |
|
|
Term
|
Definition
| microbiologists make a series of dilutions and count the number of colonies resulting from a spread or pour plate for each dilution |
|
|
Term
| viable plate count (live/dead/both?) |
|
Definition
|
|
Term
| when would it be best to use viable plate count |
|
Definition
| when even a very small sample has too many organisms to count |
|
|
Term
| what is the minimum number of colonies that must be present to use it for a viable plate count |
|
Definition
|
|
Term
|
Definition
| the chance of underestimating the population increases as the number of colonies decreases |
|
|
Term
| what four things is the V.P.C dependant on |
|
Definition
| the homogenity of the dilution, ability of the bacteria to grow on the medium used, the number of cell deaths, and the growth phase of the sample population |
|
|
Term
|
Definition
| a large sample is poured through a membrane filter with pores small enough to trap the cells |
|
|
Term
| when doing the membrane filtration the number of colonies is equal to |
|
Definition
| the number of CFU's in the original large sample |
|
|
Term
| when would you want to use the membrane filtration method |
|
Definition
| when the population density of very small |
|
|
Term
| M.F. is used to count (live/dead/or both?) |
|
Definition
|
|
Term
| microscopic counts are done |
|
Definition
| through a microscope lens |
|
|
Term
| what is microscopic counting usually suitable for |
|
Definition
| stained prokaryotes and relatively large eukaryotes |
|
|
Term
| the sample is placed on a |
|
Definition
| petroff-houser counting chamber |
|
|
Term
| what is the petroff-houser counting chamber |
|
Definition
| a slide with a grid etched on it positioned beneath the cover slip |
|
|
Term
| this method is used to count the number of bacteria per |
|
Definition
| mililiter(centimeters cubed) |
|
|
Term
| what is the calculation used |
|
Definition
| mean number of bacteria per square x 25 squares= number of bacteria per 0.02 mm cubed. x 50 = number of bacteria per mm cubed x 1000= number of bacteria per milliliter |
|
|
Term
| when are direct counting methods advantagous |
|
Definition
| when there are more than tem million cells per mL, or when a speedy estimation of the population is required |
|
|
Term
| how can direct counts be problematic |
|
Definition
| it is difficult to differentiate beteen live and dead cells, and it is difficult to count motile cells |
|
|
Term
| microscopic counts (live/dead or both? |
|
Definition
|
|
Term
|
Definition
| coulter counter and flow cytometry |
|
|
Term
|
Definition
| a device that directly counts cells as they interruptan electrical current flowing across a narrow tube held in front of an electronic detector |
|
|
Term
| this device is useful for counting |
|
Definition
|
|
Term
|
Definition
| a cytometer uses light-sensitve detector to record changes in light transmission through a tube as the cells pass |
|
|
Term
| when is flow cytometry usually used |
|
Definition
| when cells have been stained with fluorescent dyes or tagged with fluorescent antibodies |
|
|
Term
| electronic counters (live/dead/both) |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| a statistical estimation technique based on the fact that the more bacteria in a sample the more dilutions are required to reduce their number to zero |
|
|
Term
| describe how the MPN is gotten |
|
Definition
| start with three test tubes, an undiluted, a 1:10 dilution and a 1:100 dilution. inoculate 5 test tubes from each (total of 15) and inoculate for 48 hours. then record the number of test tubes that showed growth for each group. Use those three numbers to find the MPN on the chart |
|
|
Term
| the MPN is best for counting organisms that |
|
Definition
| won't grown on solid mediums, when bacteria counts are required routinely, and when samples contain too few organisms to use a viable plate count |
|
|
Term
| what are the three types of indirect methods |
|
Definition
| metabolic activity, dry weight and turbidity |
|
|
Term
|
Definition
| measuring changes in such things as nutrient utilization, waste production or pH |
|
|
Term
|
Definition
| organisms are filtered from their culture medium, dried and weighed |
|
|
Term
| turbitiy relies on the assumption that the greater the population the |
|
Definition
|
|
Term
| what instrument is used to measure turbidity |
|
Definition
|
|
Term
| sprectrophometer measures |
|
Definition
| the amount of light transmitted through the culture under standard conditions |
|
|
Term
| what is the up side to turbidity |
|
Definition
|
|
Term
| tubidity is only useful when |
|
Definition
| the concentration of cells exceeds 1 million per mL |
|
|
Term
| when would turbitiy not be useful (even if the population was the right size) |
|
Definition
| is the cells form a pellicle (a film of cells over the surface) or a sediment |
|
|
Term
| does turbidity distinguish between live and dead cells |
|
Definition
|
|
Term
|
Definition
| refers to the removal or destruction of all microbes including viruses and bacterial endospores in or on an object |
|
|
Term
| does sterilization refer to prions (infectious proteins) |
|
Definition
|
|
Term
|
Definition
| describes an environment or procedure that is free of contamination by pathogens |
|
|
Term
|
Definition
| refers to the use of physical or chemical agents (disinfectants) to inhibit or destroy microorganisms, especially pathogens |
|
|
Term
| does disinfections guarentee that all pathogens are eliminated |
|
Definition
|
|
Term
| disinfection must be used on what |
|
Definition
|
|
Term
| what is disinfection called when used on a living being |
|
Definition
| antisepsis (using antiseptics) |
|
|
Term
|
Definition
| dthe removal of microbes from a surface by scrubbing (washing your hands) |
|
|
Term
|
Definition
| the process of disinfecting places and utensils used by the public to reduce the number of pathogenic microbes |
|
|
Term
|
Definition
| the use of heat to kill pathogens and reduce the number of spoilage microbes in food and beverages |
|
|
Term
| what do the suffixes -stasis/-static mean |
|
Definition
| indicate that a chemical or physical agant inhibits microbial metabolism and growth but doesn't necessarily kill them |
|
|
Term
| what do -cide/-cidal mean |
|
Definition
| refer to agents that destroy or permanently inactivate a particular type of microbe |
|
|
Term
|
Definition
| the permanent loss of reproductive ability under ideal environmental conditions |
|
|
Term
| what is one technique used to evaluate the efficacy of an antimicrobial agent |
|
Definition
|
|
Term
| two modes of action of antimicrobial agents are |
|
Definition
| alteration of cell wall and membrane or damage to proteins and nucleic acids |
|
|
Term
| what happens when the cell wall is damaged |
|
Definition
| it no longer prevents the cells from bursting as water moves into the cell by osmosis |
|
|
Term
| what happens when the cell membrane is damaged |
|
Definition
|
|
Term
| why are the envelopes of enveloped viruses targeted? |
|
Definition
| because the envelope is what allows the virus to attach to the target cell |
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|
