Term
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Definition
| not always present. allows for "gearing up" for growth. |
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Term
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Definition
| exponential growth, characteristic of binary fission |
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Term
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Definition
| bacteria start to run out of nutrients, waste products build up, and it becomes too crowded for O2. overall colony is not dividing - cells dying = cells dividing |
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Term
| Most metabolism happens in the ____ phase of bacterial growth |
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Definition
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Term
| The ___ phase can be very long and is when more cells are dying than are dividing. |
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Definition
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Term
| Bacterial growth equation |
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Definition
N=Noe^ut
N - Number of cells
u - growth rate constant (/hr)
t - time (hr) |
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Term
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Definition
| ethanol, CO2 - are produced by normal metabolism, usually in the log phase |
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Term
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Definition
| antibiotics and endospores - used in starvation metabolism |
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Term
| Why does the death (decline) phase take so long? |
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Definition
| Persister cells - get nutrients from lysed cells for metabolism |
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Term
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Definition
| In a flask. Growth stops when wastes build up, nutrients run out, and cells become too crowded to get O2 |
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Term
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Definition
| Is in a chemostat. Growth rate determined by nutrient resupply rate. Constantly in exponential phase |
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Term
| 2 kinds of direct cell counts |
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Definition
| Petroff-Hauser Chamber (counting cell within known square), Coulter counter (interruption of electric current as cells pass through counter) |
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Term
| Disadvantages of Petrof-Hauser chamber |
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Definition
| doesn't work for motile bacteria, counts all cells dead and alive |
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Term
| Disadvantage of coulter counter |
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Definition
| counts all cells dead and alive, counts anything that passes through hole including non-cells |
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Term
| Spread plates vs. pour plates |
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Definition
Spread plates: count cells on top of agar
Pour plates: count cells w/in agar (pour bacteria first, then top w/ agar) |
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Term
| _____ is used for viable cell counts in situations with small numbers of bacteria in large volumes of water, such as water quality testing. |
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Definition
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Term
| _____ is a viable cell count that involves setting up a series of test tubes filled with solution. If bacteria are in that solution, they will produce a bubble in the tube. |
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Definition
| MPN - most probable number |
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Term
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Definition
| optical density of a culture correlates with # of cells in that culture -- depends on cell size |
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Term
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Definition
| used to measure gas escape by bacteria |
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Term
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Definition
| measures ATP production by bacteria. enzyme glows. not very sensitive. |
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Term
| 3 metabolites that can be measured to produce cell count |
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Definition
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Term
| ___ means to kill all microorganisms. |
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Definition
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Term
| ___ means to reduce the number of microbes in a culture. |
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Definition
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Term
| ___ means to kill most of the pathogens in a culture. ___ are used on inanimate surfaces, and ___ are used on living tissue. |
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Definition
| Disinfect. Disinfectant. Antiseptic. |
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Term
| ____ means to reduce the number of pathogens to a "safe" level. Often used in government agencies (USDA, FDA) |
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Definition
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Term
| ____ means to reduce the number of organisms to a "safe" level. Not specific for pathogens. |
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Definition
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Term
| ___ means to lower the growth rate of organisms enough for food to be stable long term. |
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Definition
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Term
| _____ are super resistant microbes that can only be killed by autoclaving or gluteraldehyde wash. |
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Definition
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Term
| ____ are the microbes in Giardia and cyptosporidium that are resistant to chemicals but can be killed by boiling. |
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Definition
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Term
| ____ are microbes with a waxy coat that are resistant to low-level disinfectants but can be killed with high level ones. |
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Definition
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Term
| ____ are common nosocomial organisms that are resistant to some specific disinfectants and antibiotics. |
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Definition
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Term
| What makes pseudomonas so resistant? |
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Definition
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Term
| ___ are viruses that have no lipid envelope, so they are resistant to drying and disinfectants. |
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Definition
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Term
| In decimal reduction time, it takes one unit of time to kill ___% of organisms. |
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Definition
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Term
| How long it takes to kill an organism depends on what 4 things? |
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Definition
| What disinfectant is being used, what surface it is on (porous/greasy surfaces are harder), what kind of organism it is, and how many there are. |
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Term
| ___ instruments are in direct contact with body tissue. |
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Definition
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Term
| ___ instruments are in contact with mucous membranes, such as ng tubes and endoscopes. |
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Definition
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Term
| ___ instruments are used for external contact only. |
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Definition
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Term
| How does heating kill microbes? |
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Definition
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Term
| Which is more penetrating: moist or dry heat? |
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Definition
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Term
| Boiling can disinfect but not ____. |
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Definition
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Term
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Definition
| used in USA. heat to 72C for 15 sec. creates 5 log reduction in microbe population |
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Term
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Definition
| "ultra-high temp" - sterilizes, creates long shelf life. 150C for 1 sec |
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Term
| ____ heats to 121C for 15-45min |
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Definition
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Term
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Definition
| used for liquid cultures. nitrocellulose membrane catches bacteria, but viruses get through. |
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Term
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Definition
| depth filter. used for air. organisms get caught in the filter matrix. |
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Term
| In irradiation, shorter/longer wavelengths are more penetrating because they have higher/lower energy. |
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Definition
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Term
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Definition
| uses x rays and gamma rays. kills bacteria by breaking DNA. excellent penetration, used for foods and heat-sensitive surgical materials |
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Term
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Definition
| are good for surfaces only because they don't penetrate deeply. can't break DNA but can cause mutations. Used in wastewater treatment plants. |
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Term
| ____ can be damaged by biguanides, pheolics, and quats |
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Definition
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Term
| ___ can be damaged by alcohols, aldehydes, halogens, metals, ozone, peroxygens, phenolics. |
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Definition
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Term
| ___ can be damaged by ethylene oxide, aldehydes, and radiation. |
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Definition
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Term
| ____ disinfectants kill everything but spores. They are ok for ____ instruments. |
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Definition
| High-level, semi-critical |
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Term
| ___ disinfectants kill all but spores and a few viruses. They are OK for ___ instruments. |
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Definition
| intermediate-level, non-critical |
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Term
| ___ disinfectants kill everything but mycobacteria, naked viruses, and spores. They are used where? |
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Definition
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Term
| ___ damage lipid membranes by denaturing proteins. they are a low-level disinfectant. |
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Definition
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Term
| ___ cross-link and rigidify proteins, are high-level disinfectants and sterilants. |
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Definition
| aldehydes (like formaldehyde) |
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Term
| ___ make membranes leaky, are low-level disinfectants. An example is ___, which is used in mouthwash and skin care products. |
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Definition
| Biguanides, chlorhexidine |
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Term
| ___ is a gaseous sterilant that oxidizes DNA. It is used for electronic instruments. |
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Definition
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Term
| ___ oxidize proteins, and are common in household cleaners. 2 examples are? |
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Definition
Halogens. Chlorine and Iodine. Think Clorox -- Chlorine Oxidizes |
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Term
| Chlorine is a ____ and iodine is a ___ disinfectant. |
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Definition
| sterilant, intermediate-level |
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Term
| ____ derivitize cysteine to prevent disulfide bonds. 2 examples? |
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Definition
| Heavy metals: silver nitrate, and mercury |
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Term
| ___ oxidize proteins. 2 examples? |
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Definition
| oxidizing agents. ozone and peroxides. |
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Term
| ___ is a high-level disinfectant used on surfaces, but not on skin because we have catalase. |
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Definition
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Term
| ___ dissolve lipid membranes, and are low to intermediate level disinfectants. |
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Definition
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Term
| Problem with overusing disinfectants. |
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Definition
| Bacteria become resistant to them. such as with the overuse of triclosan. |
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Term
| ___ dissolve membranes, are low-level disinfectants, and are used in hypoallergenic soaps and cosmetics. |
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Definition
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