Term
| (page 264 "damage to proteins and nucleic acids" why is damage to the protein important |
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Definition
| because the three dimensional shape fo the protein is what allows it to function |
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Term
| what two things happen when the nucleic acid of a cell is damaged |
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Definition
| fatal cell mutations and protein synthesis is stopped |
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Term
| name microorganisms from most suseptible to least |
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Definition
| enveloped viruses, gram-positive bacteria, nonenveloped viruses, fungi, gram-negative bacteria, active stage protozoa, cysts of protozoa,mycobacteria, bacterial endospores |
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Term
| what makes mycobacteria so resistant |
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Definition
| they have a large amounts of waxy lipids in their membranes |
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Term
|
Definition
| kills all pathogens including bacterial endospores |
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Term
| intermediate level germicide |
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Definition
| kills fungal spores, protozoan cysts, viruses, and pathogenic bacteria |
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Term
|
Definition
| eliminate vegetative bacteria, fungi, protozoa, and some viruses |
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Term
| what two environmental conditions that affect microbial death rates and the efficiency of antimicrobial agents |
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Definition
|
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Term
| do most antimicrobial agents work best with high or low heat |
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Definition
|
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Term
| chemical disinfectants are increased at what pH |
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Definition
|
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Term
| what else makes agents more effective |
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Definition
| high concentration and fresher solutions and longer exposure |
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Term
| what are the efficiencies of agents compared to |
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Definition
| the efficiency of Phenol (phenol coefficient) |
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|
Term
| a phenol concentration greater than one indicates |
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Definition
| that an agent is more effective than phenol |
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Term
|
Definition
| the greater the effectiveness |
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Term
|
Definition
| researchers dip metal cylinders into broth cultures of bacteria, dry, then rinse them. They are then put into a fresh medium and incubated. |
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Term
| the most effective agent is the one that |
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Definition
| doesn't show any growth after the incubation |
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Term
| what is the more realistic, but most accurate way of testing agents |
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Definition
|
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Term
| how is an in-use test done |
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Definition
| swabs are taken from actual objects, both before and after a disinfectant is added. test for growth |
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Term
| why is heat such an effective tool for disinfection |
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Definition
| because heat denatures proteins, interferes with the integrity of the cell wall, and disrupts the function of nucleic acids |
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Term
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Definition
| lowest temperature that kills all cells in a broth in ten minutes |
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Term
|
Definition
| the time it takes to completely sterilize a particular volume of liquid at a set temperature |
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Term
| decimal reduction time (D) |
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Definition
| the time it takes to destroy 90% of teh microbes in a sample |
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Term
| why is moist heat more effective than dry heat |
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Definition
| because water is a better of conducter of heat than air |
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Term
| boiling kills bacteria within |
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Definition
|
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Term
|
Definition
| to achieve higher temperatures, pressure is applied to boiling water to prevent the escape of heat as steam |
|
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Term
| what temperature and pressure is needed to kill all microbes in a small volume in about ten minutes |
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Definition
| 121 degrees celcius at 15 psi above that of normal air pressure |
|
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Term
| what are two ways scientist test the autoclave |
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Definition
| use a chemical that changes color when proper temp/psi have been reached or use endospores |
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Term
| how are endospores used to test the autoclave |
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Definition
| endospores are put on a tape and when the autoclaving is done, the tape is inoculated to see if anything grows |
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Term
| is pasterization the same as sterilization |
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Definition
|
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Term
| what is the old fashioned way to pateurize |
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Definition
| batch method (30 min at 63 degrees) |
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Term
| what is the most common type of pasteurization in use now |
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Definition
| flash pasteurization (72 degreee 15 seconds) |
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Term
| why is ultrahigh-temperature pasterization not commonly used |
|
Definition
| many consumers say it changes the taste |
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|
Term
| what method is used to kill ALL bacteria in the milk |
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Definition
| ultrahigh-temperature sterilization |
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|
Term
| what is the down side of using dry heat |
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Definition
| higher temperatures are needed for the same effect |
|
|
Term
| what does refrideration do |
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Definition
| decreases microbial metabolism, growth and reproduction because chemical reactions happen at a slower rate |
|
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Term
| what is most effective at killing microbes: fast or slow freezing |
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Definition
| slow freezing, during which ice crystals have time to form and puncture cell membranes |
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Term
|
Definition
| (drying) inhibits microbial growth because metabolism requires liquid water |
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Term
|
Definition
|
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Term
|
Definition
| the passage of fluid (either liquid or gas) through a sieve designed to trap particles, and seperate them from the fluid |
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|
Term
| what membrane are usually used |
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Definition
| circular filters manufactured of nitrocellulose or plastic and containing specific pore sizes |
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|
Term
| how does osmotic pressure preserve foods |
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Definition
| many cells can't live in a hypertonic solution |
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Term
| what are the two different forms of radiation |
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Definition
|
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Term
|
Definition
| have wavelengths shorter than 1 nm and have sufficient energy to eject electrons from atoms creating ions |
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Term
| what is the downside to using ionizing radiation to preserve foods |
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Definition
|
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Term
| what kind of radiation is nonionizing |
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Definition
| electromagnetic, does contain enough energy to excite electrons and cause them to make new covalent bonds |
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Term
| what is the type of nonionizing radiation that can be used |
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Definition
|
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Term
| what is the downside of using UV |
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Definition
| it doesn't penetrate surfaces |
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