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Questions and Answers
Which of the following is the best method to sterilize heat-labile solutions?
Which of the following is the best method to sterilize heat-labile solutions?
- Freezing
- Membrane filtration (correct)
- Dry heat
- Pasteurization
- Autoclave
Which of the following best describes the pattern of microbial death?
Which of the following best describes the pattern of microbial death?
- The pattern varies depending on the antimicrobial agent.
- The pattern varies depending on the species.
- Not all of the cells in a culture are killed.
- All the cells in a culture die at once.
- The cells in a population die at a constant rate. (correct)
Which of the following chemical agents is used for sterilization?
Which of the following chemical agents is used for sterilization?
- Alcohol
- Phenolics
- Soap
- Chlorine
- Ethylene oxide (correct)
Which of the following substances is used for surgical hand scrubs?
Which of the following substances is used for surgical hand scrubs?
Which of the following pairs of terms is mismatched?
Which of the following pairs of terms is mismatched?
The antimicrobial activity of chlorine is due to which of the following?
The antimicrobial activity of chlorine is due to which of the following?
Which of the following regarding antimicrobial control agents is FALSE?
Which of the following regarding antimicrobial control agents is FALSE?
Which of the following does NOT achieve sterilization?
Which of the following does NOT achieve sterilization?
Which of the following is a limitation of the autoclave?
Which of the following is a limitation of the autoclave?
An agent used to reduce the number of bacteria on a toilet would most accurately be called a(n)
An agent used to reduce the number of bacteria on a toilet would most accurately be called a(n)
Application of heat to living cells can result in all of the following EXCEPT
Application of heat to living cells can result in all of the following EXCEPT
Which of the following disinfectants acts by disrupting the plasma membrane?
Which of the following disinfectants acts by disrupting the plasma membrane?
Oxidizing agents include all of the following EXCEPT
Oxidizing agents include all of the following EXCEPT
Disinfection of water is achieved by all of the following EXCEPT
Disinfection of water is achieved by all of the following EXCEPT
All of the following substances are effective against nonenveloped viruses EXCEPT
All of the following substances are effective against nonenveloped viruses EXCEPT
Which of the following methods is used to preserve food by slowing the metabolic processes of foodborne microbes?
Which of the following methods is used to preserve food by slowing the metabolic processes of foodborne microbes?
Which concentration of ethanol is the most effective bactericide?
Which concentration of ethanol is the most effective bactericide?
All of the following factors contribute to hospital-acquired infections EXCEPT
All of the following factors contribute to hospital-acquired infections EXCEPT
Which of the following treatments is the most effective for controlling microbial growth?
Which of the following treatments is the most effective for controlling microbial growth?
Which of the following could be used to sterilize plastic Petri plates in a plastic wrapper?
Which of the following could be used to sterilize plastic Petri plates in a plastic wrapper?
Which of the following regarding antimicrobial control agents is FALSE?
Which of the following regarding antimicrobial control agents is FALSE?
In Figure 7.1, what is the thermal death time?
In Figure 7.1, what is the thermal death time?
In Figure 7.1, the thermal death point for this culture is
In Figure 7.1, the thermal death point for this culture is
In Figure 7.1, the decimal reduction time (D value) for the culture is approximately
In Figure 7.1, the decimal reduction time (D value) for the culture is approximately
Which of the following results in lethal damage to nucleic acids?
Which of the following results in lethal damage to nucleic acids?
Which of the following pairs is mismatched?
Which of the following pairs is mismatched?
In Table 7.1, which compound was the most effective against Staphylococcus?
In Table 7.1, which compound was the most effective against Staphylococcus?
In Table 7.1, which compound was the most effective against E.coli?
In Table 7.1, which compound was the most effective against E.coli?
In Table 7.1, which compound was bactericidal?
In Table 7.1, which compound was bactericidal?
In Table 7.2, which preservative is most effective?
In Table 7.2, which preservative is most effective?
An iodophor is a(n)
An iodophor is a(n)
Ethylene oxide
Ethylene oxide
All of the following substances are used to preserve foods EXCEPT
All of the following substances are used to preserve foods EXCEPT
In Table 7.3, which disinfectant is the most effective at stopping bacterial growth?
In Table 7.3, which disinfectant is the most effective at stopping bacterial growth?
In Table 7.3, which disinfectant was bactericidal?
In Table 7.3, which disinfectant was bactericidal?
In Table 7.3, which disinfectant was most effective against Salmonella?
In Table 7.3, which disinfectant was most effective against Salmonella?
All of the following are effective for destroying prions EXCEPT
All of the following are effective for destroying prions EXCEPT
Which of the following pairs is mismatched?
Which of the following pairs is mismatched?
All of the following are methods of food preservation EXCEPT
All of the following are methods of food preservation EXCEPT
The preservation of beef jerky from microbial growth relies on which method of microbial control?
The preservation of beef jerky from microbial growth relies on which method of microbial control?
If you were preparing nutrient agar at home and did not have an autoclave, what could you use to sterilize the nutrient agar?
If you were preparing nutrient agar at home and did not have an autoclave, what could you use to sterilize the nutrient agar?
Bone and tendons for transplant are decontaminated by
Bone and tendons for transplant are decontaminated by
Which one of the following is most resistant to chemical biocides?
Which one of the following is most resistant to chemical biocides?
Any process that destroys the non-spore forming contaminants on inanimate objects is sterilization.
Any process that destroys the non-spore forming contaminants on inanimate objects is sterilization.
Desiccation is a reliable form of sterilization.
Desiccation is a reliable form of sterilization.
The thermal death time is the time needed to kill all the bacteria in a particular culture at a certain temperature.
The thermal death time is the time needed to kill all the bacteria in a particular culture at a certain temperature.
Pseudomonas has been found growing in quaternary ammonium compounds (quats).
Pseudomonas has been found growing in quaternary ammonium compounds (quats).
Moist heat destroys organisms by denaturing proteins.
Moist heat destroys organisms by denaturing proteins.
Some antimicrobial chemicals are considered to be disinfectants and antiseptics.
Some antimicrobial chemicals are considered to be disinfectants and antiseptics.
The pH of the medium has no effect on the activity of the disinfectant being applied.
The pH of the medium has no effect on the activity of the disinfectant being applied.
Ultraviolet light (UV) causes irreversible breaks in DNA strands.
Ultraviolet light (UV) causes irreversible breaks in DNA strands.
Autoclaving is the most effective method of moist heat sterilization.
Autoclaving is the most effective method of moist heat sterilization.
Microorganisms placed in high concentrations of salts and sugars undergo lysis.
Microorganisms placed in high concentrations of salts and sugars undergo lysis.
Study Notes
Sterilization and Microbial Control Methods
- Membrane filtration is the best method for sterilizing heat-labile solutions.
- Microbial death occurs at a constant rate, not all at once.
- Ethylene oxide is an effective chemical agent for sterilization.
- Chlorhexidine is commonly used for surgical hand scrubs.
Antimicrobial Terminology
- Bacteriostatic agents inhibit growth without killing bacteria.
- Hypochlorous acid formation is responsible for chlorine's antimicrobial activity.
- Effective disinfectants disrupt microbial cell membranes, such as bisphenols.
Dysfunctions and Misconceptions
- Pasteurization does not achieve complete sterilization.
- Autoclaves cannot be used with heat-labile materials, limiting their application.
- Organic debris can reduce the effectiveness of antimicrobial agents.
Heat and Radiation Effects
- Application of heat can damage DNA and disrupt membrane integrity without always affecting thermal death time.
- Radiation methods, such as gamma radiation, are effective for sterilizing heat-sensitive items like plastic Petri dishes.
Efficacy of Disinfectants
- The effectiveness of disinfectants can be measured by zones of inhibition, with larger zones indicating greater effectiveness.
- Sodium benzoate is identified as a highly effective preservative against bacterial growth in food products.
General Microbial Resistance and Preservation
- Gram-negative bacteria are more resistant to chemical biocides than gram-positive strains.
- Various methods, including desiccation and refrigeration, are employed for food preservation, while ionizing radiation is commonly used in industrial contexts.
Miscellaneous
- Some chemicals possess dual roles, serving as both disinfectants and antiseptics.
- The pH of the medium impacts the action of disinfectants, contrary to the false belief that it has no effect.
- Ultraviolet light can cause damage to DNA but does not create irreversible breaks.
True/False Statements
- Autoclaving is confirmed as the most effective method of moist heat sterilization.
- High concentrations of salts and sugars lead to cell lysis, contrary to common belief.
Importance of Correct Practices
- Proper understanding of sterilization and microbial control methods is essential for preventing infections and ensuring safety in healthcare and food practices.
Studying That Suits You
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Description
Test your knowledge with our flashcards for Microbiology Chapter 7. This quiz covers important sterilization methods and patterns of microbial death. Challenge yourself and enhance your understanding of key microbiology concepts.
