BIO 140 LAB PRACTICAL EXAM FINAL
MICROBIOLOGY UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS
Question:
1. Identify the labeled parts (A-F) on microscope.
Answer:
A. Eyepiece/ocular
B. Objective lenses
C. Stage
D. Diaphragm
E. Course adjustment knob
F. Fine adjustment knob
Question:
2. What does it mean when we say the microscope is
parfocal?
Answer:
Specimen will remain in focus when the objective lens is
changed.
Question:
3. Which objective lenses require immersion oil?
Answer:
Only the 100X objective
Question:
4. What is the total magnification of microscope B?
Answer:
400X
,Question:
5. List the following in decreasing size order:
Answer:
Stentor,
Red blood cell,
S. aureus,
E. coli,
HIV
Question:
6. What is a disinfectant?
Answer:
Destroys harmful vegetative microbes, but not endospores, on inanimate objects.
Question:
7. What is an antiseptic?
Answer:
Destroys harmful vegetative microbes, but not endospores, on animate objects.
Question:
8. Can a substance be both a disinfectant and an antiseptic?
Answer:
Yes, alcohol, iodine, hydrogen peroxide
Question:
9. Identify the labeled substances as disinfectants or
antiseptics (A - G).
Answer:
A. 70% alcohol - both
B. 10% Lysol - disinfectant
C. Mouthwash - antiseptic
D. Quadricide - disinfectant
E. Wescodine - disinfectant
F. 3% hydrogen peroxide - both
G. Bleach - disinfectant
Question:
10. How can you measure the effectiveness of an antiseptic
or disinfectant?
Answer:
Disc diffusion assay
, Question:
11. What is the name of the technique demonstrated by plate
A?
Answer:
Kirby-Bauer method
Question:
12. How does this method differ from the method we used to
measure the effectiveness of
disinfectants and antiseptics?
Answer:
Both methods are based on the principle of disc diffusion. However, the Kirby-
Bauer method is a standardized technique specifically to assess an organism's
sensitivity to antibiotics.
Question:
13. What does the zone of inhibition indicate?
Answer:
The zone of inhibition indicates that the antibiotic diffused from the disc into the
surrounding media and prevented the bacterium from growing in the zone.
Question:
14. For plate A...
a. What is the size of the zone of inhibition for the disc
labeled CIP-5?
Answer:
~29 mm
Question:
15. b. Is this organism sensitive, resistant, or intermediate to
this antibiotic?
Answer:
Susceptible
Question:
16. Narrow spectrum antibiotics?
Answer:
small subset of bacteria
MICROBIOLOGY UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS
Question:
1. Identify the labeled parts (A-F) on microscope.
Answer:
A. Eyepiece/ocular
B. Objective lenses
C. Stage
D. Diaphragm
E. Course adjustment knob
F. Fine adjustment knob
Question:
2. What does it mean when we say the microscope is
parfocal?
Answer:
Specimen will remain in focus when the objective lens is
changed.
Question:
3. Which objective lenses require immersion oil?
Answer:
Only the 100X objective
Question:
4. What is the total magnification of microscope B?
Answer:
400X
,Question:
5. List the following in decreasing size order:
Answer:
Stentor,
Red blood cell,
S. aureus,
E. coli,
HIV
Question:
6. What is a disinfectant?
Answer:
Destroys harmful vegetative microbes, but not endospores, on inanimate objects.
Question:
7. What is an antiseptic?
Answer:
Destroys harmful vegetative microbes, but not endospores, on animate objects.
Question:
8. Can a substance be both a disinfectant and an antiseptic?
Answer:
Yes, alcohol, iodine, hydrogen peroxide
Question:
9. Identify the labeled substances as disinfectants or
antiseptics (A - G).
Answer:
A. 70% alcohol - both
B. 10% Lysol - disinfectant
C. Mouthwash - antiseptic
D. Quadricide - disinfectant
E. Wescodine - disinfectant
F. 3% hydrogen peroxide - both
G. Bleach - disinfectant
Question:
10. How can you measure the effectiveness of an antiseptic
or disinfectant?
Answer:
Disc diffusion assay
, Question:
11. What is the name of the technique demonstrated by plate
A?
Answer:
Kirby-Bauer method
Question:
12. How does this method differ from the method we used to
measure the effectiveness of
disinfectants and antiseptics?
Answer:
Both methods are based on the principle of disc diffusion. However, the Kirby-
Bauer method is a standardized technique specifically to assess an organism's
sensitivity to antibiotics.
Question:
13. What does the zone of inhibition indicate?
Answer:
The zone of inhibition indicates that the antibiotic diffused from the disc into the
surrounding media and prevented the bacterium from growing in the zone.
Question:
14. For plate A...
a. What is the size of the zone of inhibition for the disc
labeled CIP-5?
Answer:
~29 mm
Question:
15. b. Is this organism sensitive, resistant, or intermediate to
this antibiotic?
Answer:
Susceptible
Question:
16. Narrow spectrum antibiotics?
Answer:
small subset of bacteria
