course Notes For Test One Cont. ( Microbe Utilization Of Oxygen)

Question 1

Aerobe

Answer 1

-Uses oxygen in metabolic reactions
-Requires oxygen for growth

3) Pseudomonas spp. (spoilage)

Question 2

Strict Aerobe

Answer 2

Grows only in the presence of air (21% oxygen)

Question 3

Anaerobe

Answer 3

• cannot use oxygen
• Oxygen is toxic
• cannot grow in the presence of air

Question 4

Microaerophile

Answer 4

• requires a small amount of oxygen (5% for growth)
• large amounts of oxygen are toxic

-anaerobic environment inhibits growth

• 85% nitrogen, 10% CO2, 5% oxygen

Question 5

Facultative anaerobe

Answer 5

• Does not require oxygen for growth, but may use it if available

Ex. Listeria Monocytogenes

Question 6

Aerotolerant anaerobe

Answer 6

• Does not use oxygen in metabolic reactions, but can grow in its presence
• an aerobe that will tolerate air (21% oxygen)

Question 7

Psychrophile

Answer 7

• Can grow at 0C
  -optimum growth range : 15C or lower
  -maximum growth temperature: 20C
• commonly isolated from arctic environments (90% of the ocean is 5C or colder offering an ideal environment)
• Enzymes, transport systems, and protein synthesis mechanisms of psychrophiles work well at cold temperatures
  -many suffer from membrane disruption (cell may rupture, stop functioning) at temperatures higher than 20C and leak cytoplasmic constituents (cells cannot function)