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What are the 2 types of radiation used to kill microorganisms? |
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Gamma and Ultraviolet |
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What is Gamma radiation also known as? |
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Ionizing radiation, it's greatest impact is when it collides with molecules in the cell, creating free radicals which are toxic |
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What is Ultraviolet radiation also known as? |
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Non-Ionizing radiation, kills by damaging DNA |
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Give an example of UV radiation |
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formation of thymine or cytosine dimers (bonds between 2 adjacent pyrimidines in the DNA strand), these lead to mutations |
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What wavelength of UV light is most lethal? |
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200-900 nm |
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Why is UV light as a sterilzing method not a good idea? |
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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 |
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What kind of lamps are used in UV light? |
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Germicidal lamps |
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What will looking directly into UV raise cause? |
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Eye damage and cataracts, wear goggles |
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What 2 organisms were used in this experiment? |
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Bacillus cerus and Serratia |
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What were index cards used for in this experiment? |
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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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