UV Lecture

Question 1

What are the two types of radiation?

Answer 1

Ionizing radiation and non-ionizing radiation

Question 2

What are two examples of ionizing radiation?

Answer 2

X-rays and gamma rays

Question 3

What is an example of non-ionizing radiation?

Answer 3

UV

Question 4

What is the UV wave length?

Answer 4

15-400 nanometers

Question 5

What happens to wave lengths that are below 200 nm?

Answer 5

it is absorbed by air and does not reach living organisms

Question 6

What is UVC?

Answer 6

200-290 nm. most lethal- biocidal

Question 7

What is UVB?

Answer 7

290-320 nm. can cause DNA damage.

Question 8

What is UVA?

Answer 8

320-400 nm. not readily absorbed.

Question 9

How is UV light lethal?

Answer 9

UV light induces thymine- dimers in DNA which causes mutation and death

Question 10

What is photo reactivation?

Answer 10

when exposed to light, photolyases are activated

Question 11

What do photolyases do?

Answer 11

they split the dimer and restore the DNA

Question 12

What is dark repair?

Answer 12

dimer is removed by endonuclease, DNA polymerase replaces the nucleiotide and then ligase

Question 13

What are the uses of UV light for disinfection?

Answer 13

heat sensitive solutions, hospital OR, food processing, water disinfection

Question 14

What are the two limitations of using UV?

Answer 14

it affects humans and doest penetrate well