Class 12 Health Care Chapter 2 Sterilization and Disinfection

Class 12 Health Care Chapter 2 Sterilization and Disinfection Solutions English Medium As Per AHSEC New Syllabus to each chapter is provided in the list so that you can easily browse through different chapters Class 12 Health Care Chapter 2 Sterilization and Disinfection Question Answer and select need one. Class 12 Health Care Notes Download PDF. AHSEC Class 12 Elective Health Care Question Answer English Medium.

Class 12 Health Care Chapter 2 Sterilization and Disinfection

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Sterilization and Disinfection

Chapter: 2

EXERCISE

A. Fill in the Blanks:

1. Sterilization is defined as the process where all the living microorganisms, including __________ are killed.

Ans: Bacterial spores.

2. Disinfection eliminates most pathogenic microorganisms, but not __________.

Ans: Bacterial spores.

3. Dry heat acts by __________, oxidative damage and toxic effects of elevated electrolytes.

Ans: Protein denaturation.

4. The __________ oven method was introduced by Louis Pasteur.

Ans: Hot air.

5. Browne’s tube and biological spore test are used to check the __________ of sterilization.

Ans: Efficacy.

B. Short questions:

1. What is the main difference between sterilization and disinfection?

Ans: Sterilization kills all microorganisms including spores (absolute condition), while disinfection eliminates most pathogenic microorganisms excluding spores (not absolute).

2. Name two physical methods of sterilization.

Ans: Heat (dry and moist heat), Radiation (UV rays, gamma rays).

3. Why is moist heat more effective than dry heat?

Ans: Moist heat acts by coagulation and denaturation of proteins and requires lower temperature and time compared to dry heat.

4. What is the principle of the hot air oven method?

Ans: Articles are sterilized at 160°C for 60 minutes by conduction, convection, and radiation.

5. What is pasteurization?

Ans: Pasteurization is a method of heating at 63°C for 30 minutes (holder method) or 72°C for 15 seconds (flash method) to destroy milk-borne pathogens.

C. Long questions:

1. Explain in detail the factors affecting sterilization by heat.

Ans: Factors include nature of heat (moist more effective than dry), temperature and time (inversely proportional), number and type of microorganisms (spores are highly resistant), type of material (heavily contaminated items need more exposure), and presence of organic matter (proteins, fats increase time required).

2. Describe the hot air oven method of sterilization with its procedure, cycle, advantages, and disadvantages.

Ans: In a hot air oven, articles are sterilized at 160°C for 1 hr, 170°C for 40 min, or 180°C for 20 min. Articles must be dry, wrapped properly, and spaced for air circulation. The cycle includes heating, holding time, and cooling. Advantages: effective for heat-stable articles, oils, powders. Disadvantages: poor penetration, takes longer, glass may become smoky, paper slightly charred.

3. Write short notes on different physical methods of sterilization other than hot air ovens.

Ans: (i) Red heat: Direct flaming till red hot (loops, wires, forceps tips).

(ii) Flaming: Passing articles quickly over flame (slides, test tube mouths).

(iii) Incineration: Burning contaminated materials (dressings, carcasses).

(iv) Moist heat: Boiling, steaming, autoclaving, inspissation, pasteurization.

(v) Radiation: UV rays for surface disinfection, Gamma rays for deep sterilization.

(vi) Filtration: Separation of microbes using filters (membrane, sintered glass, asbestos).