4. Environmental Conditions for Bacterial Growth

Question 1

What are the temperature requirements?

Answer 1

Minimum, optimum, maximum

35-37 degrees Celsius

Question 2

Describe each of the following: psychrophilic, mesophilic, thermophilic

Answer 2

Psychrophilic - cold loving, 15-20 degrees Celsius

Mesophilic - middle loving, 25-40 degrees Celsius

Thermophilic - heat loving, 45-50 degrees Celsius

Lab incubators are set at 35 degrees Celsius

Question 3

What are Capnophilic bacteria?

Answer 3

CO2 loving

Lab methods to increase CO2:

• candle extinction jar
• GasPak, chemical generation
• carbon dioxide incubator

Question 4

What are the four groups bacteria can be divided into depending on their response to oxygen?

Answer 4

Obligate Aerobes - require atmospheric O2 for growth
Obligate Anaerobes - only grow in absence of O2
Facultative Anaerobes - can grow anaerobically but grow better in the presence of oxygen (humans)
Microaerophilic - require molecular O2 for growth but at a concentration lower than in air

Question 5

What are the main two components that contribute to bacterial growth?

Answer 5

Temperature and Atmosphere (oxygen, carbon dioxide)