Lab Assignment #16

Which type of organism requires oxygen as its final electron acceptor in the electron transport chain?

obligate aerobe

The pink color in the top of the broth in an FTM tube indicates

the presence of oxygen.

Where would you predict a facultative anaerobe would grow in a tube of fluid thioglycolate medium?

throughout the tube

If an organism grew on both plates in this experiment, what is its classification?

facultative anaerobe

Some organisms exhibit flexibility in terms of their energy harvesting reactions. If provided with oxygen, they will obtain energy through aerobic respiration. If in an environment without oxygen, they will turn to fermentation to satisfy their energy needs. These organisms are classified as

facultative anaerobes.

What type of environment is created in the GasPak jar?

anaerobic

Where would you expect obligate anaerobes to grow in an FTM culture tube?

at the bottom

Clostridium, a known obligate anaerobe, does not grow in the GasPak jar. What might be the reason for this lack of growth?

The chemical reaction failed to remove all of the oxygen in the jar.

True or false: Obligate aerobes, obligate anaerobes, aerotolerant anaerobes, and facultative anaerobes are all present at different places on/in the human body.

True

Which of the following enzymes are produced by aerobic bacteria to neutralize toxic oxygen byproducts?

catalase peroxidase

E. coli grows throughout an FTM tube. What would be its oxygen preference classification?

facultative anaerobe

Compare the growth of a facultative anaerobic organism with an aerotolerant anaerobe in a broth culture. Make sure to explain any differences.

Facultative organisms will grow throughout the tube since they can use oxygen if present but can grow in anaerobic environments if oxygen is absent. The tube will appear cloudy from top to bottom after incubation. Aerotolerant anaerobe does not use oxygen and will not be affected if oxygen is present. The tube will appear equally dispersed after incubation.

True or false: The organism inoculated onto the plates was likely a facultative anaerobe.

False

What might explain the reason why obligate anaerobes cannot grow at all in the presence of oxygen?

They lack enzymes to degrade toxic forms of oxygen.

Where would you predict an obligate anaerobe would grow in a tube of fluid thioglycolate medium?

at the bottom of the tube

A bacterial isolate is subcultured to two blood agar plates, one of which is incubated in an anaerobic jar, and the other is incubated on a shelf in the incubator. After incubation, growth is observed on the plate from the anaerobic jar, but there is no growth on the plate incubated on the incubator shelf. Based on these results, how would this organism be categorized?

obligate anaerobe

A bacterial species that cannot tolerate the presence of oxygen and will only grow in the absence of oxygen is classified as a(n)

obligate anaerobe

Which of the following organisms will grow on agar plates incubated in an anaerobic jar?

obligate anaerobe facultative anaerobe aerotolerant anaerobe