Sterilization and Disinfection
Q. What is the main difference between sterilization and disinfection?
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A.
Sterilization kills all microbes; disinfection reduces them
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B.
Disinfection kills all microbes; sterilization reduces them
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C.
Sterilization is faster than disinfection
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D.
Disinfection is only for surfaces, sterilization is for instruments
Solution
Sterilization kills all microbes, while disinfection reduces the number of viable microorganisms.
Correct Answer: A — Sterilization kills all microbes; disinfection reduces them
Q. What is the minimum temperature and time required for effective autoclaving?
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A.
121°C for 15 minutes
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B.
100°C for 30 minutes
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C.
134°C for 10 minutes
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D.
160°C for 1 hour
Solution
The minimum temperature and time for effective autoclaving is 121°C for 15 minutes.
Correct Answer: A — 121°C for 15 minutes
Q. What is the primary purpose of sterilization in microbiology?
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A.
To reduce microbial load
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B.
To eliminate all forms of microbial life
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C.
To inhibit microbial growth
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D.
To enhance microbial growth
Solution
Sterilization aims to eliminate all forms of microbial life, including bacteria, viruses, fungi, and spores.
Correct Answer: B — To eliminate all forms of microbial life
Q. What is the role of a biological indicator in sterilization?
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A.
To measure temperature
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B.
To confirm the presence of microorganisms
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C.
To verify the effectiveness of the sterilization process
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D.
To indicate the type of sterilization method used
Solution
Biological indicators are used to verify the effectiveness of the sterilization process by confirming the destruction of specific microorganisms.
Correct Answer: C — To verify the effectiveness of the sterilization process
Q. Which chemical agent is commonly used for high-level disinfection?
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A.
Ethanol
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B.
Chlorine
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C.
Glutaraldehyde
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D.
Hydrogen peroxide
Solution
Glutaraldehyde is widely used for high-level disinfection of medical equipment.
Correct Answer: C — Glutaraldehyde
Q. Which of the following is a common use of alcohol in disinfection?
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A.
Sterilizing surgical instruments
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B.
Disinfecting skin before injections
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C.
Cleaning surfaces in laboratories
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D.
Preserving biological samples
Solution
Alcohol is commonly used to disinfect skin before injections due to its rapid antimicrobial action.
Correct Answer: B — Disinfecting skin before injections
Q. Which of the following is a disadvantage of using bleach as a disinfectant?
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A.
It is ineffective against viruses
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B.
It can corrode surfaces
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C.
It is too expensive
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D.
It requires long contact time
Solution
Bleach can corrode surfaces, which is a significant disadvantage when used as a disinfectant.
Correct Answer: B — It can corrode surfaces
Q. Which of the following is a physical method of sterilization?
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A.
Ethylene oxide gas
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B.
Autoclaving
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C.
Chlorine bleach
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D.
Hydrogen peroxide
Solution
Autoclaving is a physical method of sterilization that uses steam under pressure.
Correct Answer: B — Autoclaving
Q. Which of the following is NOT a method of disinfection?
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A.
Ultraviolet light
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B.
Autoclaving
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C.
Chemical disinfectants
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D.
Boiling water
Solution
Autoclaving is a method of sterilization, not disinfection, as it kills all microorganisms including spores.
Correct Answer: B — Autoclaving
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