Physical Methods Used To Destroy Microorganisms And Viruses

Front 1

moist heat

Back 1

denatures proteins. relatively fast, reliable, safe, and inexpensive.

Hint 1

widely used.

Front 2

boiling

Back 2

destroys most microorganisms and viruses except for endospores

Hint 2

treats drinking water.

Front 3

pressurized steam (autoclaving)

Back 3

typical treatment: 121*C/15psi for 15 min or longer, destroys endospores

Hint 3

sterilizes microbiological media, laboratory glassware, surgical instruments, and other items steam can penetrate.

Front 4

incineration

Back 4

burns cell components to ashes

Hint 4

flaming of wire inoculating loops. also used to destroy medical wastes and contaminated animal carcasses.

Front 5

dry heat ovens

Back 5

destroys cell components and denatures proteins. less efficient than moist heat, requiring longer times and higher temperatures.

Hint 5

laboratory glassware is sterilized by heating at 160*C to 170*c for 2-3 hours. powders, oils, and other dry materials are also sterilized in ovens.

Front 6

filtration of fluids

Back 6

various pore sizes are available; 0.2 micrometers is commonly used to remove bacteria

Hint 6

used for beer and wine, and to sterilize some heat-sensitive medications

Front 7

filtration of air

Back 7

HEPA filters are used to remove microbes that have a diameter of 0.3 micrometers or greater

Hint 7

used in biological safety cabinets, specialized hospital rooms, and airplanes. also used in some vacuum cleaners and home air purification units.

Front 8

ionizing radiation

Back 8

destroys DNA and possibly damages cytoplasmic membranes. produces reactive molecules that damage other cell components. items can be sterilized even after packaging.

Hint 8

used to sterilize heat-sensitive materials including medical equipment, disposable surgical supplies, and drugs (penicillin). also used to destroy microbes in spices, herbs, and approved types of produce and meats.

Front 9

UV radiation

Back 9

damages DNA. penetrates poorly.

Hint 9

used to destroy microbes in the air and drinking water, and to disinfect surfaces.

Front 10

high pressure

Back 10

treatments of 130,000 psi are thought to denature proteins and alter the permeability of the cell. products retain color and flavor.

Hint 10

used to extend the shelf life of certain commercial food products such as guacamole.