Microbiology questions for Chapter 7 Flashcards


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1

Sterilization is the:

Destruction of all forms of microbial life.

2

An antiseptic is used when one needs to remove microbes from:

Skin, prior to injection

3

Foods to be canned need not be sterile. However, all of Clostridium botulinum must be killed.

Enodpores

4

Some antimicrobial treatments kill microbes; some inhibit growth. Which term refers to an agent that inhibits bacterial growth?

Bacteriostatic.

5

Which of the following is not a major target for action of antimicrobials?

Flagella

6

Decimal reduction time is the time in minutes in which of the population at a given temperature will be killed.

90%

7

Which is not a characteristic of the autoclave?

The requirement for long (hours) exposure times

8

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.

9

Choose the best method for the sterilization of an enzyme solution.

A) Freezing.

B) Dry heat.

C) Filtration.

D)Treatment with phenol.

E)Autoclave.

Filtration

10

The bactericidal effect of UV light is attributed to damage to:

DNA

11

Some microbes are very resistant to antimicrobial chemicals. Which of the following would be the easiest to kill?

A)Pseudomonas aeruginosa

B) Mycobacterium tuberculosis

C) E. coli

D) cysts of Protozoa

E) Clostridium endospores

E. Coli

12

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.

Clear Zone

13

The first disinfectant used by Lister was

Phenol

14

Alcohol is most effective when used as a solution.

70%

15

Which chemical was once used to treat the eyes of newborn babies to kill N. Gonorrhoeae?

Silver Nitrate

16

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.

D) Xanthan.

E) Sorbic acid.

Xanthan

17

The more microbes present in a sample, the ____________________ it takes to eliminate the microbial population.

Longer

18

The ____________________ is the lowest temperature at which all microorganisms in a liquid suspension will be killed in 10 minutes.

Thermal Death Point

19

Dry heat kills by ____________________ , similar to the slow charring of paper in a heated oven.

Oxidation

20

____________________ is a common household disinfectant that has been used to disinfectant everything from dairies to drinking water.

Bleach

21

A zone of growth inhibition around a copper penny on a plate that had been swabbed with bacteria demonstrates the ____________________ of copper

oligodynamic action

22

____________________ has little value as an antiseptic but is important in the mechanical removal of microbes.

Soap

23

Oxidizing agents are useful for irrigating deep wounds where released oxygen will inhibit the growth of ____________________ .

anaerobic bacteria

24

__________________ can grow in solutions of quaternary ammonium compounds

Pseudomonas

25

____________ are commonly used as food preservatives in spite of their conversion to the carcinogenic products called nitrosamines.

Nitrates

26

_______ ammonia compounds are less effective against gram-negative bacteria and more effective against gram-positive bacteria.

Quaternary

27

Microbes vary with respect to sensitivity to an antimicrobial agent.

True

28

The presence of organic matter, such as blood or saliva, speeds the action of antimicrobial chemicals.

False

29

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.

True

30

Aldehydes, alcohols, and halogens kill bacteria by the same method of action

False

31

UV radiation and X ray radiation are similar in that they damage DNA and have a high penetrating power.

False

32

Soap is ineffective in killing bacteria. Therefore, hand washing is a rather ineffective measure in preventing disease transmission.

False

33

70% ethyl alcohol is a more effective bactericide than 100% alcohol.

True