Topic 3 – Week 2: Sterilization & Disinfection

What is the goal of sterilization?

• Kill viruses only

• Eliminate vegetative bacteria

• Destroy all microbial forms including spores

• Prevent microbial growth

Which method kills most bacteria but not spores?

• Sterilization

• Disinfection

• Autoclaving

• Pasteurization

Which agent prevents bacterial growth but doesn’t kill bacteria?

• Bactericidal

• Antiseptic

• Bacteriostatic

• Sporicidal

The most efficient method of sterilization is:

• Dry heat

• Pasteurization

• Autoclaving

• Filtration

Autoclaving requires which conditions?

• 15 psi at 121°C for 15–20 mins

• 100°C for 10 mins

• 180°C for 2 hours

• 0°C under vacuum

Boiling water can kill:

• Spores

• All microbial forms

• Only viruses

• Vegetative forms of microorganisms

Which method uses live steam for 3 days to kill spores?

• Autoclaving

• Tyndallization

• Dry heat

• UV light

What is the primary action of heat in sterilization?

• DNA replication

• Protein synthesis

• DNA breakage and protein denaturation

• Cell wall disruption

Which of the following is preferred for sterilizing glassware?

• UV radiation

• Autoclave

• Hot air oven

• Incineration

What is the mechanism of action of UV light?

• Breaks cell wall

• Coagulates proteins

• Forms thymine dimers in DNA

• Destroys lipids