Microbiology questions for Chapter 7 Flashcards
Sterilization is the:
Destruction of all forms of microbial life.
An antiseptic is used when one needs to remove microbes from:
Skin, prior to injection
Foods to be canned need not be sterile. However, all of Clostridium botulinum must be killed.
Some antimicrobial treatments kill microbes; some inhibit growth. Which term refers to an agent that inhibits bacterial growth?
Which of the following is not a major target for action of antimicrobials?
Decimal reduction time is the time in minutes in which of the population at a given temperature will be killed.
Which is not a characteristic of the autoclave?
The requirement for long (hours) exposure times
Milk that you have never opened spoils in the refrigerator. A sample reveals the presence of microorganisms. The most likely explanation is:
The microbes that survived pasteurization were able to grow at 4 °C.
Choose the best method for the sterilization of an enzyme solution.
B) Dry heat.
D)Treatment with phenol.
The bactericidal effect of UV light is attributed to damage to:
Some microbes are very resistant to antimicrobial chemicals. Which of the following would be the easiest to kill?
B) Mycobacterium tuberculosis
C) E. coli
D) cysts of Protozoa
E) Clostridium endospores
In the filter paper method used for evaluation of antimicrobial chemicals, the effectiveness of a chemical is indicated by a around a disc immersed with the test chemical.
The first disinfectant used by Lister was
Alcohol is most effective when used as a solution.
Which chemical was once used to treat the eyes of newborn babies to kill N. Gonorrhoeae?
The following may be listed on the ingredients of your favorite snack food. Which of the following is not antimicrobial?
A) Potassium sorbate.
B) Calcium propionate.
C) Sodium benzoate.
E) Sorbic acid.
The more microbes present in a sample, the ____________________ it takes to eliminate the microbial population.
The ____________________ is the lowest temperature at which all microorganisms in a liquid suspension will be killed in 10 minutes.
Thermal Death Point
Dry heat kills by ____________________ , similar to the slow charring of paper in a heated oven.
____________________ is a common household disinfectant that has been used to disinfectant everything from dairies to drinking water.
A zone of growth inhibition around a copper penny on a plate that had been swabbed with bacteria demonstrates the ____________________ of copper
____________________ has little value as an antiseptic but is important in the mechanical removal of microbes.
Oxidizing agents are useful for irrigating deep wounds where released oxygen will inhibit the growth of ____________________ .
__________________ can grow in solutions of quaternary ammonium compounds
____________ are commonly used as food preservatives in spite of their conversion to the carcinogenic products called nitrosamines.
_______ ammonia compounds are less effective against gram-negative bacteria and more effective against gram-positive bacteria.
Microbes vary with respect to sensitivity to an antimicrobial agent.
The presence of organic matter, such as blood or saliva, speeds the action of antimicrobial chemicals.
Times required for sterilization in an autoclave are shorter than those required in a dry oven because moist heat penetrates biological specimens more effectively than does dry heat.
Aldehydes, alcohols, and halogens kill bacteria by the same method of action
UV radiation and X ray radiation are similar in that they damage DNA and have a high penetrating power.
Soap is ineffective in killing bacteria. Therefore, hand washing is a rather ineffective measure in preventing disease transmission.
70% ethyl alcohol is a more effective bactericide than 100% alcohol.