Lab 17: Effect of UV Light

Question 1

UV light does what to electrons

Answer 1

excites electrons causing them to create new covalent bonds

Question 2

what is the most effective wavelength for thymine dimers

Answer 2

265 nm

Question 3

how do cells repair thymine dimers?

Answer 3

w/ enzymes

Question 4

UV light forms _______ in DNA

Answer 4

thymine (pyrimidine) dimers

Question 5

what cells are less susceptible to UV

Answer 5

cells w/ thicker walls like endospores

Question 6

UV is suitable for the use of disinfecting…

Answer 6

• air
• transparent fluids
• surfaces of objects
• used in water facilities

Question 7

how long did it take to kill S. epi?

Answer 7

3 mins

Question 8

how long did it take to kill B. mag?

Answer 8

6 mins

Question 9

why did B. mag take twice as long to die than S. epi?

Answer 9

b/c B. mag is a sporeformer meaning that it has thicker cell walls

Question 10

which molecule is the target of UV light? How is the damage actually caused?

Answer 10

thymine in DNA

by causing adjacent thymines to interact with one another, forming covalent bonds and creating thymine dimers