LAB 24: Killing by Ultraviolet Light

Question 1

what is the main focus of Lab 24?

Answer 1

UV light and radiation

Question 2

give a case study summary

Answer 2

8 patients w severe respiratory diseases went to 3 different ERs with similar symptoms (cough and fever)…diagnosis was Legionnaire’s disease (pneumonia but worse) from community spa. Used UV to disinfect and prevent future outbreaks

Question 3

what are two types of radiation?

Answer 3

gamma (more toxic) and UV light (what we used)

Question 4

what wavelength is best to be most lethal?

Answer 4

200-290 nanometers
-more absorbed by DNA

Question 4

what are the limitations of UV light?

Answer 4

poor penetration through hard surfaces (plastic, glass)

Question 4

what is UV light often used on?

Answer 4

on top of surfaces, in air and in water

Question 5

where can you often kill microbes?

Answer 5

on top of surfaces, in air purifiers, and in water

Question 6

what organisms were used in lab 24?

Answer 6

Staphylococcus and Bacillus

Question 7

why did we use an older culture of Bacillus?

Answer 7

used for mature spores
(can withstand uvlight more)

Question 8

why did we use a notecard to cover half the culture?

Answer 8

to show the difference in UV light penetration
(growth without notecard vs covered with notecard)