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45 Cards in this Set
- Front
- Back
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Each of the following is a target of antimicrobial agents except..
ribosomes cell walls cell membranes chloroplasts cellular proteins. |
chloroplasts |
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The use of a physical or chemical process to destroy vegetative pathogens on inanimate objects is
degermation sterilization disinfection antisepsis. |
disinfection |
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Disinfection of beverages such as apple juice, milk, and wine is optimally achieved by
pasteurization chlorination moist heat autoclave filtration boiling water |
pasteurization
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____ radiation excites atoms to a higher energy state within molecules such as DNA that then leads to the formation of pyrimidine dimers.
infared Ultraviolet Gamma Particle Ionizing |
ultraviolet |
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The process of killing or removing all of the microorganisms in or on a material is termed
sterilization disinfection sanitation antisepsis |
sterilization |
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Which will require a longer time to kill?
A larger population of microorganisms. A smaller population of microorganisms. Killing will be equally as rapid in a large or a small microbial population. There is no way to predict which will require a longer kill time. |
A larger population of microorganisms.
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Which kind of sterilization procedure takes advantage of the size of microorganisms? autoclaving open flame use of chemicals filtration |
filtration |
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Dry heat takes a much shorter time to sterilize material than wet heat.
T/F |
False |
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Physical agents for controlling microbial growth include all of the following except
pasteurization hydrogen peroxide ultraviolet radiation boiling water |
hydrogen peroxide |
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Which of the following inhibits bacterial growth but does not kill bacteria
Lysozyme Bactericidal agent Bacteriostatic agent Antiseptic agent. |
Bacteriostatic agent
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The Black Death killed about _________________ of the population of the continent
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1/3 |
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Etiological agent of the Black Plague
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Yersinia pestis a gram (-) bacilis disease causing bacteria |
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Vector of the Black Plague |
fleas, rats, gerbils way the bacteria spreads |
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With the Bubonic Plague, bacteria localize in the _________________________, especially in the axillary and groinarea.
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lymph nodes |
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If the Black Plague goes untreated there is a _____ chance mortality rate. |
50% |
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Methods of controlling microbial growth 1) 2) |
1) Physical 2) Chemical |
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Destroying all forms of life
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Sterilzation |
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Destroying and/or inhibiting pathogens or unwanted organisms
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Disinfection |
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Antimicrobial agent used on inanimate objects |
disinfectant |
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antimicrobial agent used on living tissue |
antiseptic |
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Killing bacteria |
bactericidal |
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inhibits bacterial growth |
bacteriostatic |
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removal of microbes from a limited area such as using an alcohol swab to clean an injection site |
degerminig |
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Factors that affect antimicrobial activity of disinfectants (4)
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1) number of microbes- the more you start with the harder they are to kill 2) environmental influences- the presence of bio films interfere. Temperature (disinfectants usually work better with warm temps. 3) time of exposure-may need an extended time to affect more resistant microbes 4) microbial characteristics -somme bacteria are harder to get rid of than others (spores, gram (-), mycobacterium) |
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What is the type of bacteria that is the most resistant to disinfectants? |
Prions |
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Cellular targets of antimicrobial agents
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1.Alteration of membrane permeability.
2. Cell wall and ribosomes (for antibiotics) 3. Enzymes and other proteins 4. Alter DNA and RNA |
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Lowest temperature at which all themicrobes and their endospores in a liquid culture are killed in 10 minutes
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Thermal Death Point (TDP) |
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minimum length of time in which allmicrobes and their endospores in a liquid culture are killed at a given temperature
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Thermal Death Time (TDT) |
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most commonly used sterilizationmethod
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autoclave (steam under pressure) |
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What is the main problem with pasteurization? |
thermoduric bacteria (bacteria that can survive high temps) |
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gamma rays and x-rays, penetrate most surfaces by disrupting DNA and RNA structures Used on substances that could be damaged by heat: plastic petri dishes, syringes, catheters,surgical gloves
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Ionizing Radiation |
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gas used to sterilize plastic (cheaper way, used in lab) |
ethylene oxide |
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Does NOT penetrate plastic, glass, or proteinaceous matterCauses pyrimidine dimers. Used to reduce microbial populations in: hospital rooms, operating rooms, biotechnology workbenches and fume hoods
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Non-ionizing radiation-UV light
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DNA replication occurs at the... |
Replication fork |
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Replication always occurs in what direction? |
5'-3' |
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What enzyme unwinds DNA? |
DNA helicase |
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What enzyme relaxes supercoiling? |
DNA gyrase |
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Which strand of DNA is synthesized continuously? |
Leading strand |
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Because of the lagging strands orientation the DNA is added in chunks called... |
Okazaki fragments |
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What are the three enzymes needed on the lagging strand? |
RNA primate (makes RNA primer) DNA polymerase (extends the primer and digests RNA and replaces it with DNA) DNA ligase (seals the okazaki fragments) |
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What is the start codon and what does it code for? |
AUG, Met |
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What are the three stop codons? |
UAA, UGA, UAG |
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A series of structural genes under control of one regulatory gene |
Operon |
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Operons that have to be turned on in order for the genes to be translated.. |
Inducible (lac operon) |
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Operons that are transcribed until they are turned off. |
Repressable (tryptophan operon) |
