Question 1

Which of the following methods is most effective for sterilizing heat-sensitive medical equipment such as plastic syringes?

Accepted Answer

Ethylene oxide gas sterilization

Question 2

A hospital needs to sterilize a batch of nutrient broth that contains heat-labile vitamins. Which method should be used to ensure sterility without destroying the vitamins?

Accepted Answer

Filtration using a membrane filter with pore size $0.22\ \mu m$

Question 3

Which of the following statements best explains why autoclaving is more effective than boiling for sterilization?

Accepted Answer

Autoclaving uses higher pressure, allowing temperatures above $100^\circ$C to be reached, which kills bacterial endospores.

Question 4

A food manufacturer wants to preserve jam without refrigeration. Which method is most likely to be used and why?

Accepted Answer

Increasing osmotic pressure by adding high concentrations of sugar, which draws water out of microbial cells

Question 5

Which of the following is NOT a limitation of filtration as a sterilization method?

Accepted Answer

It cannot be used for heat-sensitive solutions

Question 6

A nurse is preparing a patient’s skin before an injection. Which of the following best describes the process and the agent used?

Accepted Answer

Antisepsis using alcohol to reduce microbial load on living tissue

Question 7

Why is refrigeration considered a method of microbial control, and what is its main limitation?

Accepted Answer

It slows microbial growth but does not kill most microbes, so spoilage can still occur over time

Question 8

Which of the following best explains why soaps and detergents are effective in controlling microbial populations on hands?

Accepted Answer

They physically remove microbes from the skin through emulsification and rinsing

Question 9

A wound dressing is impregnated with silver. What is the primary reason for using silver in this context?

Accepted Answer

Silver acts as an antimicrobial agent, inhibiting bacterial growth

Question 10

Which of the following halogens is commonly added to drinking water and toothpaste for its antimicrobial properties?

Accepted Answer

Fluorine ($F_2$)

Question 11

A laboratory technician needs to sterilize a solution that would be destroyed by heat or radiation. Which method should be used?

Accepted Answer

Filtration through a membrane filter

Question 12

Which of the following statements about alcohols as disinfectants is correct?

Accepted Answer

Isopropanol is generally more effective than ethanol and is commonly used for swabbing skin

Question 13

Which of the following is the best explanation for why pasteurization does not achieve sterilization?

Accepted Answer

It uses lower temperatures that kill most pathogens but not all microbes or spores

Question 14

A researcher is comparing the effectiveness of various antiseptics. According to the study materials, which of the following is likely to be the least effective?

Accepted Answer

Soap and water

Question 15

Which of the following best describes the principle behind using high concentrations of salt in food preservation?

Accepted Answer

It creates a hypertonic environment, causing microbial cells to lose water by osmosis

Question 16

Which of the following is a key difference between disinfection and antisepsis?

Accepted Answer

Disinfection is used on inanimate objects, while antisepsis is used on living tissue

Question 17

A hospital is considering using ultraviolet (UV) radiation to sterilize surgical instruments. What is a major limitation of this method?

Accepted Answer

UV radiation does not penetrate well, so it is ineffective for sterilizing surfaces that are not directly exposed

Question 18

Which of the following best explains why endospores are more resistant to heat than vegetative cells?

Accepted Answer

Endospores have a tough outer coat and low water content, making them less susceptible to heat damage

Question 19

A patient with a burn wound is treated with a dressing containing silver. Which property of silver is most important in this context?

Accepted Answer

Silver ions disrupt microbial enzymes and cell membranes

Question 20

Which of the following is the main reason why ethylene oxide is used for sterilizing items wrapped in paper?

Accepted Answer

Ethylene oxide gas can penetrate paper and destroy microbes without damaging heat-sensitive materials

Control of Microbial Growth: Methods and Applications ~ Chp 7

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