Lesson 2.3: Oxygen Requirements

Question 1

Oxygen relationships of microorganisms

Obligate Aerobes

Answer 1

require oxygen
aerobic respiration
Micrococcus luteus (skin, dust)

Question 2

Oxygen relationships of microorganisms

Facultative Anaerobes

Answer 2

do not require oxygen, but grows better with it

aerobic and anaerobic respiration, fermentation

E.coli

Question 3

Oxygen relationships of microorganisms

Microaerophilic

Answer 3

required but low levels (microoxic conditions)

Aerobic respiration

Question 4

Oxygen relationships of microorganisms
Anaerobes

Answer 4

does not respire oxygen

Question 5

Oxygen relationships of microorganisms
Aerotolerant

Answer 5

tolerate oxygen but do not use it
fermentation

Question 6

Oxygen relationships of microorganisms

obligate anaerobes

Examples

Answer 6

inhibited or killed by oxygen

Clostridium- gram-pos, spore-forming

methanogens

Question 7

Growth of bacteria on the medium based on their oxygen requirement

Answer 7

Obligate aerobes- top
Facultative anaerobes- grow throughout
Microaerophiles - grow near the top
Anaerobes- bottom

Question 8

Methods of culturing for aerobic

Answer 8

shaking flasks or bubbling air

Question 9

Methods of culturing for strict anaerobes

Answer 9

incubation in oxygen-free gas chamber
anoxic glove bags
remove trace oxygen