Culturing Microbes

Question 1

Defined Media / Minimal Media

Answer 1

All the components are known

Synthetic

Question 2

Media

Answer 2

Includes:
carbon source
nitrogen source
water
phosphorus
sulfur

Question 3

Undefined Media / Complete Media

Answer 3

Contents are unknown

Don’t care because the cells will grow

Question 4

Selective Media

Answer 4

Special media that you make so that only certain microbes will grow
Eg. If you want nitrogen fixing bacteria, make media without a nitrogen

Question 5

Differential Media

Answer 5

Allows you to see the difference between microbes

Eg. xgal added so that only those bacteria that have B-galactosidelase will turn blue

Question 6

Sterilization - various ways

Answer 6

Autoclave - pressurized cooker, heat to sterilize
Need pressure so that the boiling temperature of water can go up to 121 C without boiling
Filter - use for heat sensitive media (0.2-0.45 um filter), can trap bacteria but not viruses

Question 7

Establishing a pure culture

Answer 7

Use streaking

Question 8

Storage of pure culture

Answer 8

Short - 4 C
Long - -80 C, need to add glycerol or DMSO to reduce the size of the ice crystals so that you don’t directly kill the cells once the water expands
Forever - lyophilization (free dry)