Тест: Sterilization Techniques and Principles — 7 въпроса

1. What does moist heat sterilization primarily refer to in microbial control?

A. Heating materials at high temperature without moisture to oxidize microbial components

B. Heating liquids to boiling point to eliminate vegetative bacteria and viruses

C. Sterilization using steam under pressure at high temperature to kill all microorganisms including spores

D. Disinfection of surfaces by applying moist heat to reduce microbial load

Answer: (C)

Обяснение

Moist heat sterilization primarily involves the use of steam under pressure, such as autoclaving, to effectively destroy all forms of microbial life, including spores. This process relies on coagulation and denaturation of proteins, making it a reliable sterilization method. The other options describe related but different heat treatments: disinfection, boiling, and dry heat sterilization, respectively.

2. What is the primary effect of dry heat sterilization on microorganisms?

A. It induces oxidative damage leading to protein denaturation.

B. It results in physical removal of microbes from surfaces.

C. It chemically alters microbial DNA to prevent replication.

D. It causes dehydration of microbial cells.

Answer: (A)

Обяснение

Dry heat sterilization primarily kills microorganisms through oxidative damage, which denatures proteins. This process involves high temperatures that cause oxidative damage to microbial proteins, leading to cell death. Dehydration is more associated with moist heat, physical removal with filtration, and chemical alteration involves chemical sterilants, not dry heat.

3. When sterilizing heat-sensitive surgical instruments that cannot withstand moisture, which method should be applied in practice based on the concept of sterilization?

A. Employ chemical sterilants like Ethylene Oxide for all heat-sensitive instruments.

B. Apply dry heat in a hot air oven at 160-170°C for 1-2 hours to avoid moisture damage.

C. Use flaming directly over a Bunsen flame for sterilization.

D. Use autoclaving at 121°C under pressure to ensure complete microbial destruction.

Answer: (B)

Обяснение

Dry heat sterilization, such as in a hot air oven at 160-170°C, is suitable for heat-sensitive instruments that cannot tolerate moisture, as it destroys microbes through oxidative damage without involving moisture. Autoclaving is not suitable for moisture-sensitive items, flaming is impractical for surgical instruments, and chemical sterilants are used for specific applications but are not the primary method for heat-sensitive surgical tools.

4. What is a key characteristic of moist heat sterilization using an autoclave?

A. It employs steam under pressure at 121°C for 15 minutes.

B. It uses dry heat at 160°C for 2 hours.

C. It uses UV light exposure for surface sterilization.

D. It involves boiling liquids at 100°C for 30 minutes.

Answer: (A)

Обяснение

Autoclaving, the most reliable moist heat sterilization method, uses steam under pressure at 121°C for 15 minutes, as explicitly stated in the source. This combination of temperature and pressure ensures effective microbial destruction, including spores.

5. When was the hot air oven sterilization method established as a standard practice for sterilizing heat-resistant materials?

A. During the 18th century

B. In the mid-19th century

C. In the early 20th century

D. In the late 20th century

Answer: (C)

Обяснение

The hot air oven sterilization method, which uses heated air at 160-170°C for 1-2 hours, has become a standard practice mainly in the 20th century as laboratories and hospitals adopted more reliable dry heat sterilization techniques for heat-resistant materials.

6. Who proposed the theory of natural selection as a mechanism for evolution?

A. Charles Darwin

B. Alfred Russel Wallace

C. Gregor Mendel

D. Jean-Baptiste Lamarck

Answer: (A)

Обяснение

Charles Darwin published On the Origin of Species in 1859, proposing natural selection. Lamarck proposed inheritance of acquired characteristics, Mendel studied genetics, and Wallace independently conceived a similar theory but Darwin is primarily credited.

7. Which biological spores are used to monitor the effectiveness of moist heat sterilization?

A. Geobacillus stearothermophilus spores

B. Bacillus subtilis spores

C. Bacillus atrophaeus spores

D. Clostridium difficile spores

Answer: (A)

Обяснение

The source states that spores of Geobacillus stearothermophilus are used to verify the efficacy of moist heat sterilization processes, such as autoclaving, making it the correct choice over other options.