BIOD 171 MICROBIOLOGY REAL QUESTIONS + VERIFIED ANSWERS -
LATEST VERSION - TOP RATED (2026/2027)
1. What is the primary purpose of aseptic technique?
• A) To kill all microorganisms
• B) To prevent contamination of cultures and protect the worker
• C) To speed up bacterial growth
• D) To identify unknown bacteria ANSWER : B
2. Which biosafety level is most commonly used in teaching microbiology
labs?
• A) BSL-1
• B) BSL-2
• C) BSL-3
• D) BSL-4 ANSWER : B
3. When should hands be washed in the microbiology laboratory?
• A) Only at the end of lab
• B) Before and after lab activities
• C) Only if visibly contaminated
• D) Once per week ANSWER : B
4. What should you do if you spill a bacterial culture on the bench?
• A) Wipe it immediately with a paper towel
• B) Cover with disinfectant, wait, then clean up
• C) Leave it for the instructor
• D) Ignore small spills ANSWER : B
5. Which of the following is NOT appropriate lab attire?
• A) Closed-toe shoes
, • B) Lab coat
• C) Sandals
• D) Safety goggles ANSWER : C
6. The Bunsen burner creates a sterile field approximately how far around
the flame?
• A) 1-2 inches
• B) 6-8 inches
• C) 12-15 inches
• D) 20-24 inches ANSWER : B
7. Why do we flame the mouth of culture tubes?
• A) To kill bacteria on the rim
• B) To warm the medium
• C) To create updrafts preventing airborne contamination
• D) Both A and C ANSWER : D
8. What concentration of bleach solution is typically used for disinfecting
lab benches?
• A) 1%
• B) 5%
• C) 10%
• D) 50% ANSWER : C
9. Which of the following is considered a biological hazard?
• A) Bacterial cultures
• B) Bunsen burner flames
• C) Broken glassware
• D) Chemical spills ANSWER : A
10. When should safety goggles be worn in the microbiology lab?
• A) Only when working with acids
• B) When handling liquid cultures or when splashing is possible
, • C) Never, regular glasses are sufficient
• D) Only during unknown identification ANSWER : B
11. What does autoclave sterilization use to kill microorganisms?
• A) Dry heat only
• B) Steam under pressure
• C) Chemical disinfectants
• D) UV radiation ANSWER : B
12. The typical temperature and pressure for autoclaving is:
• A) 100°C at 0 psi
• B) 121°C at 15 psi
• C) 160°C at 30 psi
• D) 200°C at 50 psi ANSWER : B
13. How long should materials typically be autoclaved?
• A) 5 minutes
• B) 15-20 minutes
• C) 1 hour
• D) 4 hours ANSWER : B
14. What should you do if you get a culture in your eye?
• A) Rub your eye immediately
• B) Rinse at eyewash station for 15 minutes and notify instructor
• C) Wait until end of lab to wash
• D) Use hand sanitizer ANSWER : B
15. Which of the following can be sterilized in an autoclave?
• A) Glass petri dishes
• B) Heat-sensitive plastics
• C) Electronic equipment
• D) Paper notebooks ANSWER : A
, 16. What is the purpose of the incinerator loop sterilizer?
• A) To heat media
• B) To sterilize inoculating loops quickly
• C) To dispose of cultures
• D) To melt agar ANSWER : B
17. Before leaving the lab, you should:
• A) Disinfect your work area
• B) Wash your hands
• C) Remove your lab coat
• D) All of the above ANSWER : D
18. Eating and drinking in the microbiology lab is:
• A) Allowed if you wash hands first
• B) Allowed only during breaks
• C) Never allowed
• D) Allowed with instructor permission ANSWER : C
19. What should be done with contaminated pipette tips?
• A) Throw in regular trash
• B) Dispose in biohazard sharps container
• C) Wash and reuse
• D) Leave on the bench ANSWER : B
20. Which statement about lab coats is correct?
• A) They should be worn outside the lab
• B) They protect your clothing and skin from contamination
• C) They can be taken home for washing
• D) They are optional ANSWER : B
21. The zone of inhibition in antibiotic testing represents:
• A) Bacterial growth
LATEST VERSION - TOP RATED (2026/2027)
1. What is the primary purpose of aseptic technique?
• A) To kill all microorganisms
• B) To prevent contamination of cultures and protect the worker
• C) To speed up bacterial growth
• D) To identify unknown bacteria ANSWER : B
2. Which biosafety level is most commonly used in teaching microbiology
labs?
• A) BSL-1
• B) BSL-2
• C) BSL-3
• D) BSL-4 ANSWER : B
3. When should hands be washed in the microbiology laboratory?
• A) Only at the end of lab
• B) Before and after lab activities
• C) Only if visibly contaminated
• D) Once per week ANSWER : B
4. What should you do if you spill a bacterial culture on the bench?
• A) Wipe it immediately with a paper towel
• B) Cover with disinfectant, wait, then clean up
• C) Leave it for the instructor
• D) Ignore small spills ANSWER : B
5. Which of the following is NOT appropriate lab attire?
• A) Closed-toe shoes
, • B) Lab coat
• C) Sandals
• D) Safety goggles ANSWER : C
6. The Bunsen burner creates a sterile field approximately how far around
the flame?
• A) 1-2 inches
• B) 6-8 inches
• C) 12-15 inches
• D) 20-24 inches ANSWER : B
7. Why do we flame the mouth of culture tubes?
• A) To kill bacteria on the rim
• B) To warm the medium
• C) To create updrafts preventing airborne contamination
• D) Both A and C ANSWER : D
8. What concentration of bleach solution is typically used for disinfecting
lab benches?
• A) 1%
• B) 5%
• C) 10%
• D) 50% ANSWER : C
9. Which of the following is considered a biological hazard?
• A) Bacterial cultures
• B) Bunsen burner flames
• C) Broken glassware
• D) Chemical spills ANSWER : A
10. When should safety goggles be worn in the microbiology lab?
• A) Only when working with acids
• B) When handling liquid cultures or when splashing is possible
, • C) Never, regular glasses are sufficient
• D) Only during unknown identification ANSWER : B
11. What does autoclave sterilization use to kill microorganisms?
• A) Dry heat only
• B) Steam under pressure
• C) Chemical disinfectants
• D) UV radiation ANSWER : B
12. The typical temperature and pressure for autoclaving is:
• A) 100°C at 0 psi
• B) 121°C at 15 psi
• C) 160°C at 30 psi
• D) 200°C at 50 psi ANSWER : B
13. How long should materials typically be autoclaved?
• A) 5 minutes
• B) 15-20 minutes
• C) 1 hour
• D) 4 hours ANSWER : B
14. What should you do if you get a culture in your eye?
• A) Rub your eye immediately
• B) Rinse at eyewash station for 15 minutes and notify instructor
• C) Wait until end of lab to wash
• D) Use hand sanitizer ANSWER : B
15. Which of the following can be sterilized in an autoclave?
• A) Glass petri dishes
• B) Heat-sensitive plastics
• C) Electronic equipment
• D) Paper notebooks ANSWER : A
, 16. What is the purpose of the incinerator loop sterilizer?
• A) To heat media
• B) To sterilize inoculating loops quickly
• C) To dispose of cultures
• D) To melt agar ANSWER : B
17. Before leaving the lab, you should:
• A) Disinfect your work area
• B) Wash your hands
• C) Remove your lab coat
• D) All of the above ANSWER : D
18. Eating and drinking in the microbiology lab is:
• A) Allowed if you wash hands first
• B) Allowed only during breaks
• C) Never allowed
• D) Allowed with instructor permission ANSWER : C
19. What should be done with contaminated pipette tips?
• A) Throw in regular trash
• B) Dispose in biohazard sharps container
• C) Wash and reuse
• D) Leave on the bench ANSWER : B
20. Which statement about lab coats is correct?
• A) They should be worn outside the lab
• B) They protect your clothing and skin from contamination
• C) They can be taken home for washing
• D) They are optional ANSWER : B
21. The zone of inhibition in antibiotic testing represents:
• A) Bacterial growth
