Directions:Multiple choice. Circle the correct answer. Total of 23 points.
1. Which of the following does not kill
c. Hot air sterilization
d. Free flowing steam
e. None of these
2. Which of the following is best to sterilize
c. Membrane filtration
d. Boiling water
3. Which of the following substances can
a. 70% Ethanol
b. Sodium benzoate
c. 8% Formaline
d. Sodium hypochlorite
4. Which of the following is used for surgical
a. Cresyl acetate
b. Chlorine bleach
d. Tincture of iodine
5. Which of the following is not a heavy metal
b. Mercuric bichloride
e. Zinc oxide
6. These agents are also usually
7. Which of the following is not true about
a. Greater activity against
b. Outer membrane of
c. Viricidal against
d. Ineffective against tubercule
e. None of the above
Exam II Page 2
8. Which of these disinfectants acts by protein
e. All of these
9. Which of these is an alkylating agent?
b. Hydrogen peroxide
e. ethylene oxide
10. Which of the following treatments is the
pasteurization of milk?
a. 62.9C for 30 min.
b. 71.6C for 15 sec.
c. 61.7C for 30 min.
d. Only a and b.
e. Only b and c.
11. Which of the following treatments does not
yield a sterile
a. Moist heat at
121.5 C for 15 min.
b. Moist heat at 135
C for 3 min.
c. Moist heat at
71.6C for 15 sec.
d. Dry heat at 160C
for 3 hr.
e. None of the
12. A classmate is trying to determine how a
kill cells. You observed
that when he spilled
the disinfectant in your
reduced litmus milk,
the litmus turned blue
again. You suggest
to your classmate that
a. The disinfectant
might inhibit cell wall
b. The disinfectant
might oxidize molecules.
c. The disinfectant
might inhibit protein
disinfectant might denature
e. He take his work
away from yours.
13. Which of the following pairs is not
- ophthalmia neonatorum
b. Betadine -
c. Cresyl acetate -
antiseptic and analgesic
d. 10% H2O2
- deep wounds
e. None of these
14. Which of the following statements is true
non-germicidal soaps over a
soaps have a persistant
effect on skin over time.
soaps reduce bacterial
count by half over four days.
soaps are just as effective
germicidal soaps in reducing microbial
d. microbial count
actually increases two-fold
using non-germicidal soaps.
e. there is no
sustained effect of
non-germicidal soaps on reduction of
Exam II Page 3
15. All of the following antibiotics inhibit
16. Effects of antimicrobial agents on cell
blocking its synthesis,
digesting it, or
breaking down its surface.
Which of the
following is mismatched?
a. penicillin -
b. lysozyme -
c. lystophin -
d. detergents -
disrupts cell wall
e. alcohol -
17. All of the following act by competitive
e. None of these.
18. Which of the following antibiotics are used
a. 1, 2, and 3
b. 3 and 4
c. 3, 4, and 5
d. 4 and 5
e. All of the
19. These agents work as microbicidal agents
because they lower
surface tension of cell
e. dry heat
20. In testing for the drug susceptibility of
concept of therapeutic
a. the smallest
concentration of drug that
visibly inhibits growth.
b. the zone of
inhibition around a disc in a
c. the largest zone
size compared to the
smallest zone size.
d. the ratio of
the drug's toxic dose to its
minimum effective dose.
e. both b and c are
21. Which of the following descriptions of
chemotherapeutic agents are
a. acyclovir -
herpes simplex virus
b. ribavirin -
respiratory syncytial virus (RSV)
c. azidothymidine -
d. interferon -
produced naturally by infected
e. none of these
Exam II Page 4
22. Which of the following statements regarding
antifungal agents is
a. amphotericin B -
b. nystatin -
c. griseofulvin -
d. flucytosine -
e. none of
23. Uses of antiparasitic drugs includes all of
a. mebendazole -
b. quinine -
c. chloroquine -
d. metronidazole -
Part B Directions- Matching. Match the physical
method on the left with the statement on the
right. Multiple answers are possible. Total of 12
C. mechanical disruption
E. cold temperature
F. osmotic pressure
H. ultraviolet light
K. gamma rays
__A__the first step in many disinfecting
__E__works by slowing down enzymatic
__F__employed in preserving jams and
__G__mode of action is photo-oxidation.
__D__important in helping to stop fungal
__D__used to preserve powdered drugs.
__F__not effective against halophitic
__J__used to disinfect natural pigments in
__H__causes thymine dimers
Exam II Page 5
Part C Directions Matching. Write the letter (s)
the term in the space next to the description that
it matches. Two points for each correct letter.
Total of 30 points.
D. ammonium hydroxide
H. bile salts
L. polymyxin B
N. benzalkonium chloride
R. benzoic acid
S. phenoxymethyl penicillin
T. amphotericin B
X. procaine penicillin
_W_ from Streptomyces species. DOC for
methicillin resistant organisms.
_X__ repository penicillin.
_N__ cationic detergent.
_L__ polypeptide antibiotic from Bacillus
used in topical preparations.
_H__ anionic detergent.
_G__ semisynthetic penicillin used for
beta-lactamase resistant organisms.
_B__ antimetabolite whose structure
nicotinamide, and is used against
_K__ aminoglycoside used for resistant
_O__ macrolide antibiotic, inhibits protein
synthesis, DOC for Legionnaires disease
_J__ DOC for dermatophytes. Interferes with
_Q__ sulfone used against Mycobacterium
_M__ aminoglycoside used for Plague and
_V__ a penicillin substitute used for people
hypersensitive to penicillin.
_P__ inhibits RNA synthesis and is a first
drug against tuberculosis.
_C__ Inhibits RNA synthesis and is DOC for
Exam II Page 6
Part D Directions- Essay. Answer each question
the space provided. The value of each question is
indicated in parenthesis. Total of 35 points.
1. Discuss the influence of concentration (0.1,
and 5 %) of phenol on its cidal
Influenced by time. (3 pt)
1%-20 to 30 min-cidal
5%- 2 to 3 min-cidal
2. When discussing the effectiveness of an agent
in controlling microorganisms,
related to the organism is its
Discuss how the previous history
ability of an agent to control
Young (log phase)- easy to kill since metabolically active.
mature (stationary phase)- hard to kill since low metabolism, capsules.
very old ( death phase)- easy to kill since sitting in toxic wastes.
3. What are the modes of action of dry heat as a
method of controlling
microorganisms? (3 pt)
dehydration- remove water necessary for enzymes.
protein coagulation after prolonged heating
4. Why is moist heat considered more destructive
than dry heat? (4 pt)
quicker penetration and faster destruction due to moisture
5. Describe the use of chemicals which are
coagulants. Are they narrow or
spectrum? Are they used
topically? Explain. (6 pt)
broad spectrum. used topically since protoplasmic poisons.
Exam II Page 7
6. What are the two common pore diameters of
microbiological filters? Discuss
sterilize or disinfect. (4 pts)
0.45 micrometers- disinfects
0.2 micrometers- disinfects since viruses (0.02 micrometers) can pass through
7. Compare the effectiveness of methanol,
ethanol and isopropanol as
Which is more
effective and why? Are they
disinfectants? Explain. (6
isopropyl most effective since higher molecular weight disinfectants since not
effective against spores
8. Explain the modes of action (i.e., how an
active group is converted to an
for non-specific chemical
combination. (6 pt)
protein oxidation- E-SH (sulfhydryl) group > E-S-S-E (mercaptide)
alkylating agent- CH2O (formaldehyde) + E-SH > inactive E-S-CH2-OH