Question

Obligate anaerobes which are sensitive to O2 would be found growing

A. only at the very top of a tube of thioglycolate broth
B. approximately one-third of the way down the thioglycolate broth.
C. only at the bottom of a tube of thioglycolate broth.
D. throughout a tube of thioglycolate broth.

Answer 1

Step-by-step explanation:

Obligate anaerobes are microorganisms that require an oxygen-free environment to grow and are sensitive to oxygen. Thioglycolate broth is a common culture medium used for growing microorganisms and is commonly used to test the oxygen requirements of bacteria.

The medium in a tube of thioglycolate broth is rich in nutrients and contains a reducing agent, which helps to create an anaerobic environment in the lower part of the tube. The oxygen concentration gradually decreases as you move down the tube, and the concentration of reducing agents increases.

Based on this information, we can determine that obligate anaerobes that are sensitive to O2 would be found growing at the bottom of a tube of thioglycolate broth, where the oxygen concentration is lowest and the environment is most anaerobic. Therefore, the correct answer is option C: only at the bottom of a tube of thioglycolate broth.