UV & Autoclave

Question 1

What is the wavelength of visible light?

Answer 1

~400 nm - ~750 nm

Question 2

What is the wavelength range of Ultraviolet (UV) light?

Answer 2

~100 nm - 400 nm

Question 3

What is UV radiation called?

Answer 3

non-ionizing radiation

Question 4

Why is UV light damaging to cells?

Answer 4

because it causes thymine dimers in DNA

Question 5

What can thymine dimers in DNA lead to?

Answer 5

mutations during DNA replication

Question 6

What can kill microbes?

Answer 6

an accumulation of mutations

Question 7

What is UV light used for?

Answer 7

used to control microbial growth in both laboratory & residential situations

Question 8

Downside to using UV light?

Answer 8

UV does not penetrate materials well, so it is used mainly as a surface sterilizer

Question 9

How does an autoclave work?

Answer 9

uses moist heat (steam) to sterilize both liquid & solid materials

Question 10

What does the standard auto clave conditions involve?

Answer 10

121C, 15 psi, for 20 mins

Question 11

What do autoclaves kill?

Answer 11

endospores, bacteria, fungi, & viruses, generally do not inactivate prions

Question 12

What are autoclaves used for?

Answer 12

to sterilize equipment, culture media, & biological waste

Question 13

What is it critical to do with an autoclave?

Answer 13

to regularly test the function

Question 14

What are the 2 ways to test the autoclave?

Answer 14

1. heat-sensitive autoclave tape
2. biological indicator

Question 15

Steps for a biological indicator

Answer 15

1. label 2 tubes
2. place tube 1 in autoclave for a normal run
3. do not autoclave tube 2
4. crush both tubes so that the purple culture medium is released onto filter paper that has G. stearothermophilus endospores
5. incubate at 55-50C for 24 hours
6. assess color of tubes, if tube 1 is purple & tube 2 is yellow then the autoclave is functioning correctly