why does e.coli and s.aureus still grow in areas exposed to ultraviolet light
Added by Andrew L.
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UV light can damage the DNA of microorganisms, leading to mutations or cell death. However, the effectiveness of UV light depends on factors such as intensity, duration of exposure, and the specific wavelength of UV light used. Show more…
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Why was there still E. coli growth after UV exposure? How can you explain this result? Did any colonies of D. radiodurans grow on the unexposed side of the TSA plate? Explain.
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Lab 2-12: The Effect of Ultraviolet Radiation on Microbial Growth With the exception of 0 minutes, the lids of the petri plates were removed. Side A was exposed to UV light. Side B was covered with a paper index card. Plates were incubated for 24 hours, and then growth was assessed on the plates: 0 = no growth; 1 = individual colonies; 2 = sparse confluent growth; 3 = heavy confluent growth. 1. Which organism survived the longest exposure to UV light? EXPLAIN IN DETAIL WHY YOU SUPPOSE IT DID. 2. What is the general relationship between bacterial death and UV exposure time? 3. Why were you told to remove the plate covers prior to exposing them to UV? 4. What was the purpose of covering half of the plate with a paper index card when exposing the plate to UV? 5. What specific wavelengths are most detrimental to bacteria? EXPLAIN WHY. 6. Which phase of bacterial growth, logarithmic or stationary, would Bacillus subtilis show the best survival to UV light? EXPLAIN WHY. 7. Give a specific example of how UV light is commonly used to disinfect within the healthcare setting.
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