Lab 24 Control Of Microbial Growth: UV Irradiation Of Bacteria


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Side ASide B
What are the 2 types of radiation used to kill microorganisms?
Gamma and Ultraviolet
What is Gamma radiation also known as?
Ionizing radiation, it's greatest impact is when it collides with molecules in the cell, creating free radicals which are toxic
What is Ultraviolet radiation also known as?
Non-Ionizing radiation, kills by damaging DNA
Give an example of UV radiation
formation of thymine or cytosine dimers (bonds between 2 adjacent pyrimidines in the DNA strand), these lead to mutations
What wavelength of UV light is most lethal?
200-900 nm
Why is UV light as a sterilzing method not a good idea?
It has poor penetrating ability, will not go through plastic, glass and many other materials. B/C of this, is is mainly used to kill microbes on the surfaces, in air, or in water
What kind of lamps are used in UV light?
Germicidal lamps
What will looking directly into UV raise cause?
Eye damage and cataracts, wear goggles
What 2 organisms were used in this experiment?
Bacillus cerus and Serratia
What were index cards used for in this experiment?
While half of the plates were exposed to UV light, the other half was covered with an index card to indicate non-exposure to UV light

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