40 Questions
What is the primary reason for using 0.22 µm size filters for sterilization?
The pore size is smaller than that of bacteria
What is the purpose of using syringe filters?
For sterilization, by forcing the fluid through the disc (membrane) by pressing the piston of the syringe
What is the primary mechanism by which radiation damages microbial DNA?
Ionization and free radical production (gamma-rays and electrons) or excitation (UV light)
Which type of radiation is considered less damaging and less lethal?
UV light
Which microorganisms are most resistant to irradiation?
Bacterial spores and viruses
What is the purpose of using HEPA filters?
To decontaminate the air input into operation rooms, drug filling cubicles and laminar flow cabinets
What is the purpose of using Serratia Marcescens in testing bacterial filters?
To test the efficiency of bacterial filters
What type of radiation is used to sterilize large volumes of liquid or air?
Gamma-rays and accelerated electrons
What is the most effective bactericidal wavelength of UV light, and why is it so effective?
The most effective bactericidal wavelength of UV light is around 260 nm, which is the wavelength most effectively absorbed by DNA, thereby interfering with DNA replication.
What types of microorganisms are more resistant to UV light, and why?
Bacterial spores are generally more resistant to UV light than vegetative cells.
What are some of the applications of UV light in disinfection?
UV light is used to disinfect drinking water and enclosed areas such as entryways, hospital wards, operating theatres, laboratories, and ventilated safety cabinets.
What is the primary mechanism by which ionizing radiation damages DNA?
Ionizing radiation damages DNA through various mechanisms, including radiolysis of water, which contributes to damaging processes.
What is the purpose of using a cobalt-60 source in radiation sterilization?
The cobalt-60 source is used to produce high-energy gamma-rays for radiation sterilization of heat-sensitive products.
What are the two types of electron accelerator machines used in radiation sterilization?
The two types of electron accelerator machines are the electrostatic accelerator and the microwave linear accelerator.
What is the maximum energy of electrons produced by the microwave linear accelerator?
The maximum energy of electrons produced by the microwave linear accelerator is 10 MeV.
Why is radiation sterilization generally applied to articles in the dried state?
Radiation sterilization is generally applied to articles in the dried state because undesirable changes can occur in irradiated preparations, especially those in aqueous solution.
What is the primary purpose of calculating the holding sterilization timing in an autoclave?
To ensure proper sterilization of the materials
What type of materials are particularly suited for sterilization using an autoclave?
Materials that are water-containing, permeable, or wettable and not liable to be damaged by the process
What is the purpose of using Bacillus stearothermophilus spores in biological control?
To test the effectiveness of sterilization by detecting the presence or absence of growth
What is the significance of the color change in a Browne's tube during chemical control?
The change from red to green indicates proper sterilization
What is the primary mechanism of filtration that ensures the exclusion of all particles above a defined size?
Sieving
What is the unique characteristic of filtration as a sterilization technique?
It removes, rather than destroys, microorganisms
What is the purpose of using thermocouples in autoclave sterilization?
To monitor and control the temperature during the sterilization process
What type of materials are typically sterilized using filtration?
Heat-labile materials, such as sera, solutions of sugars or antibiotics
What type of filters are synthetic membrane filters derived from, and what is their characteristic?
Synthetic membrane filters are derived from cellulose esters or other polymeric materials, and they approximate most closely to sieve filters.
Which type of filters rely primarily on mechanisms of adsorption and entrapment, and what are some examples of these filters?
Fibrous pads, sintered glass, and sintered ceramic products rely primarily on mechanisms of adsorption and entrapment.
What is the primary application of filters in the sterilization of pharmaceuticals, ophthalmic solutions, and culture media?
Heat-sensitive solutions are sterilized using filters.
What is the purpose of using filters for the separation of bacteriophages and bacterial toxins from bacteria?
Filters are used to separate bacteriophages and bacterial toxins from bacteria.
What is the characteristic of Earthware filters, and what are some examples of these filters?
Earthware filters are manufactured in several different grades of porosity, and examples include Chamberland, Doulton, Berkefeld, and Mandler filters.
What is the composition of Asbestos filters, and how are they used?
Asbestos filters are made up of a disc of asbestos (magnesium trisilicate) supported on a perforated metal disc within a metal funnel.
What is the process of preparing Sintered glass filters, and what is the characteristic of these filters?
Sintered glass filters are prepared by size grading powdered glass followed by heating, and they are characterized by their porosity.
What are the common materials used to manufacture Membrane filters, and what is their range of porosity?
Membrane filters are manufactured from a variety of polymeric materials such as cellulose nitrate, cellulose diacetate, polycarbonate, and polyester, and they have a range of porosity from 0.015 to 12 µm.
What is the primary difference between high-level disinfectants and intermediate-level disinfectants in terms of their effectiveness against microbial spores?
High-level disinfectants can generally approach sterilization in effectiveness, whereas spore forms can survive intermediate-level disinfection.
What type of instruments or devices are typically treated with low-level disinfectants, and why?
Non-critical instruments and devices, such as blood pressure cuffs, electrocardiogram electrodes, and stethoscopes, are treated with low-level disinfectants because they do not penetrate through mucosal surfaces or into sterile tissues.
What is the primary mechanism of action of surface active disinfectants, such as phenolic compounds and alcohols?
They damage the cell membrane.
What is the common mechanism of action of acids and alkalis, as well as certain alcohols?
They denature proteins.
Which type of disinfectants are used to clean surfaces or instruments that are unlikely to be contaminated with bacterial spores and other highly resilient organisms?
Intermediate-level disinfectants.
What is the common mechanism of action of heavy metals and their compounds, as well as oxidizing agents like halogens and hydrogen peroxide?
They modify functional groups of proteins and nucleic acids.
What is the purpose of using high-level disinfectants, such as glutaraldehyde and hydrogen peroxide, for certain types of endoscopes and surgical instruments?
These instruments are involved in invasive procedures and cannot withstand sterilization procedures.
What is the characteristic of quaternary ammonium compounds, making them suitable for use as low-level disinfectants?
They do not penetrate through mucosal surfaces or into sterile tissues.
This quiz covers the process of sterilization using an autoclave, including the timing and procedures for sterilizing various materials. It also mentions the different types of materials that can be sterilized using this method.
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