Principles of Epidemiology and Microbiology
Lesson 3: Practical Application of Microbiology
Exercises: Lesson 3
EXERCISES, LESSON 3
INSTRUCTIONS. The following exercises are to be answered by marking the lettered response that best answers the question or by completing the incomplete statement or by writing the answer in the space provided at the end of the question.
After you have completed all the exercises, turn to “Solutions to Exercises” at
the end of the lesson and check your answers.
1. Crustaceans are important in the sanitation of natural bodies of water in that they
help to control ___________________________.
2. The presence of rotifers in water is an indication of _________ pollution levels.
a. Low.
b. High.
3. Bacteria of the genera Escherichia and Enterobacter are known as _________
_________________ bacteria.
4. The activated sludge process in sewage treatment is based upon __________
________________________digestion.
5. In anaerobic sewage digestion, _____________________ forming bacteria
predominate in the first stage, and __________________forming bacteria
become active in the second stage.
6. The septic tank is an example of _____________________ digestion.
7. The destruction of all microorganisms is known as ____________________.
8. The destruction of all pathogenic organisms id known as __________________.
9. Microorganisms may be destroyed by either _______________________ or
__________________ agents.
10. The most widely used and effective means of sterilization is ____________.
11. The thermal death point is the temperature at which a specific organism will be kill
after ________________________ minutes of exposure.
12. Dry heat requires __________ temperatures than moist heat to accomplish
sterilization.
a. Higher.
b. Lower.
13. Moist heat requires a ___________ exposure time than dry heat for complete
sterilization.
a. Longer.
b. Shorter.
14. The most common means of sterilization are ____________________________.
15. Which of the following statements is valid?
a. Sub-freezing temperatures are effective as a means of sterilization.
b. Very low temperatures inhibit the growth and multiplication of microorganisms,
but usually do not kill the microbes.
16. The standard for measuring the germicidal effectiveness of antiseptics is that of
_________________________________.
17. Alcohol is most effective as a disinfectant when applied in a concentration of
___________________________ percent.
18. The two halogens normally used as disinfectants are ________________ and
___________________.
19. Detergents accomplish sanitization primarily through the process of reducing
__________________________.
20. A 37-40 percent solution of formaldehyde gas in water is known as ___________.
21. Instruments, containers, and other equipment coming in contact with microbiological specimens must be ______________________________.
22. List, in order, the layers from the center outward of a microbiological specimen
properly packed for shipment:
a. Infectious b . Noninfectious
________________ __________________
________________ __________________
________________ __________________
________________ __________________
________________ __________________
________________ __________________
________________ __________________
________________ __________________
