Which of the following regarding antimicrobial control agents is FALSE? O A true antimicrobial control agent is equally effective against both bacteria and viruses. O Some agents kill by denaturing DNA. O Some agents kill by an oxidation reaction Some agents kill by denaturing enzymes. Submit Request Answer Which of the following is the best method to sterilize heat-labile solutions? O membrane filtration O low temperature O autoclave O moist heat Submit Request Answer Which of the following methods is used to preserve food by slowing the metabolic processes of foodborne microbes? pasteurization osmotic pressure moist heat sterilization freezing Submit Request Answer Which of the following does NOT achieve sterilization? incineration O autoclave O ethylene oxide pasteurization Submit Request Answer Part A Which of the following is a limitation of the autoclave? It can only be used with glassware, It cannot kill endospores. t requires extra time to achieve sterilization. It cannot be used with heat-labile materials. Submit Request Answer Which of the following regarding antimicrobial control agents is FALSE? Alcohols effectively inactivate nonenveloped viruses by attacking lipids. Some agents kill by inhibiting vital cellular functions. Silver is used for treating antibiotic-resistant bacteria. Some agents work by mechanical removal of microbes. Submit Request Answer All of the following substances are effective against nonenveloped viruses EXCEPT alcohol. iodine. ethylene oxide. None of the answers is correct. Submit Request Answer Bone and tendons for transplant are decontaminated by aldehydes. plasma sterilization. autoclave. supercritical fluids. Submit Request Answer Which of the following chemical agents is used for sterilization? chlorine lodine supercritical fluids mercury Submit Request Answer Which of the following pairs is mismatched? copper algicide O alcohols open wounds SO2 food preservation O H2O2 open wounds silver-sulfadiazine wound dressings Submit Request Answer Which of the following disinfectants acts by disrupting the plasma membrane? O nitrates Ophenol soaps O iodine
The Correct Answer and Explanation is :
Correct Answers:
- Which of the following regarding antimicrobial control agents is FALSE?
- Answer: A true antimicrobial control agent is equally effective against both bacteria and viruses.
- Explanation: This statement is false because antimicrobial agents generally have varying levels of effectiveness against different types of microorganisms. Bacteria and viruses have different structures and replication mechanisms, so agents that target one might not necessarily target the other effectively. For example, antibiotics target bacterial structures like cell walls, which viruses lack. Similarly, antiviral agents focus on viral replication processes, which are distinct from bacterial metabolic pathways.
- Which of the following is the best method to sterilize heat-labile solutions?
- Answer: Membrane filtration
- Explanation: Heat-labile solutions cannot be sterilized by heat methods like autoclaving or moist heat, as they may degrade. Membrane filtration is the best method for sterilizing heat-sensitive liquids, as it physically removes microbes through a filter with pores small enough to trap bacteria and viruses.
- Which of the following methods is used to preserve food by slowing the metabolic processes of foodborne microbes?
- Answer: Freezing
- Explanation: Freezing slows down the metabolic processes of microbes, thus inhibiting their growth and prolonging the shelf life of food. It does not kill all microorganisms but slows them down significantly. Pasteurization and osmotic pressure are also used for food preservation but do not directly slow microbial metabolism in the same way freezing does.
- Which of the following does NOT achieve sterilization?
- Answer: Pasteurization
- Explanation: Pasteurization does not achieve sterilization; instead, it reduces the number of pathogens in food and beverages by heating them to a specific temperature for a set period. Sterilization refers to the complete elimination of all microorganisms, which is achieved through methods like autoclaving or incineration.
- Which of the following is a limitation of the autoclave?
- Answer: It cannot be used with heat-labile materials.
- Explanation: Autoclaving uses high-pressure steam and heat to sterilize equipment. However, it is unsuitable for heat-labile materials, such as plastics and certain chemicals, because they may be damaged by the high temperatures.
- Which of the following regarding antimicrobial control agents is FALSE?
- Answer: Alcohols effectively inactivate nonenveloped viruses by attacking lipids.
- Explanation: Nonenveloped viruses are resistant to alcohol because alcohol primarily disrupts the lipid membranes of enveloped viruses, and nonenveloped viruses lack these lipid layers. Alcohol is less effective against nonenveloped viruses.
- All of the following substances are effective against nonenveloped viruses EXCEPT:
- Answer: Alcohol
- Explanation: Alcohol is generally ineffective against nonenveloped viruses because it targets lipid membranes, which nonenveloped viruses do not have. Iodine, ethylene oxide, and some other chemical agents can effectively inactivate nonenveloped viruses.
- Bone and tendons for transplant are decontaminated by:
- Answer: Supercritical fluids
- Explanation: Supercritical fluids, especially supercritical carbon dioxide, are used to sterilize biological tissues like bone and tendons for transplants. These fluids have unique properties that allow them to penetrate tissues and effectively sterilize them without damaging the tissue.
- Which of the following chemical agents is used for sterilization?
- Answer: Supercritical fluids
- Explanation: Supercritical fluids are one of the few chemical agents capable of sterilizing biological materials and equipment. Chlorine, iodine, and mercury are disinfectants but do not achieve sterilization.
- Which of the following pairs is mismatched?
- Answer: H2O2 open wounds
- Explanation: Hydrogen peroxide (H2O2) is sometimes used on wounds, but it can be too harsh, damaging tissue and delaying healing. Silver sulfadiazine, on the other hand, is more commonly used in wound dressings for its antimicrobial properties.
- Which of the following disinfectants acts by disrupting the plasma membrane?
- Answer: Phenol
- Explanation: Phenol and its derivatives are known to disrupt the plasma membrane of microorganisms, leading to leakage of cellular contents and microbial death. Nitrates, soaps, and iodine do not act through this mechanism.
Each of these answers highlights key concepts about the different methods and agents used for antimicrobial control, focusing on sterilization, disinfection, and preservation, and explaining the differences between them.