Microbiology Lab 2-2024- Questions With Verified Answers For Aseptic Technique & Culturing Microbe

Microbiology Lab 2-2024- Questions With Verified Answers For Aseptic Technique & Culturing Microbe What is the difference between a bactericidal and bacteriostatic agent? - correct answer Bactericidal refers to killing bacteria Bacteriostatic refers to inhibiting the growth of bacterial cells What is the difference between sterilization and disinfecting? - correct answer Sterilization is the complete destruction or elimination of all viable organisms in or on an object. There are no degrees of sterilization; an object is either sterile or it is not. Sterilization procedures involve the physical removal of cells or the use of heat, radiation, or chemicals. List five sterilization methods, how they work, and what they are used for. - correct answer 1. Incineration burns organisms and physically destroys them. This method is used for needles, inoculating wires, glassware, etc. 2. Boiling at 100oC for 30 minutes kills almost all endospores. Very long or intermittent boiling is required to kill endospores and sterilize a solution. Note: For the purpose of purifying drinking water, boiling at 100oC for five minutes is probably adequate. However, there have been some reports that Giardia cysts can survive this process. 3. Autoclaving (steam under pressure or pressure cooker) at 121oC for 15 minutes (15lbs/in2 pressure) is good for sterilizing almost anything; however, autoclaving will denature or destroy heat-labile substances. 4. Dry heat (hot air oven) at 160oC for 2 hours or 170oC for 1 hour is used for glassware, metal, and objects that will not melt.