Ultraviolet Disinfection

Question 1

What is UV light primarily used to disinfect?

Answer 1

• smooth surfaces and clear liquids

- cannot penetrate for into solid material

Question 2

How does UV light cause damage?

Answer 2

• UV light between 200- 280 nm cause lesions called pyramiding dimers
  
  • when a cell with p.d attempts to replicate its DNA, the lesions lead to mutations, changes in the base- pair sequence of the DNA

Question 3

What does EMR stand for?

Answer 3

-electromagnetic radiation

Question 4

What are some forms of ionizing radiation?

Answer 4

• x rays
• gamma rays
• electron beams

Question 5

How does ionizing radiation EMRS cause damage?

Answer 5

• they are so energetic that they convert water molecules into highly reactive hydroxyl radicals which damage DNA and other cellular components.
  
  • the hydroxyl radicals cause double stranded DNA breaks, resulting in mutations that make the microorganism unable to survive and reproduce

Question 6

What are x-rays and gamma rays used to sterilize?

Answer 6

• medical devices

- reduce the microorganism contamination of meats, fruits, vegetables

Question 7

What is radiation?

Answer 7

-refers to forms of energy, like EMR, that are emitted from an object

• Some can cause damage, but it is also controllable
  
  • radiation does not persist in an object

Question 8

What is radioactivity?

Answer 8

-refers to the ability of a material to emit radiation

• the radiation they emit causes cellular damage
  
  • can increase risk of cancer

-while radioactive substances emit radiation, exposure to radiation does not make a substance radioactive

Question 9

Can microwaves be used to kill microbes?

Answer 9

-kill microbes by heat only (not specifically microbicidal, though high temps are)

Question 10

EMR with long and short wavelengths carries different amounts of energy, what are the differences?

Answer 10

EMR with long wavelengths: little energy

EMR with short wavelength: highly energetic