When performing the O/F test, one tube is covered with mineral oil and one tube is left uncovered. Why is one tube covered with mineral oil?
A) To create an anaerobic (fermentative) environment
B) To create an aerobic (oxidative) environment
C) To create a reductive environment
D) To create an asaccharolytic environment

Question

Quizplus · Accepted Answer

The tube covered with mineral oil creates an anaerobic environment, which is necessary for detecting the fermentation ability of the microorganism being tested. The absence of oxygen allows for the utilization of an alternative electron acceptor (such as nitrate) during respiration, leading to the production of acid and a color change in the medium. The uncovered tube allows for a control group to compare the results to, as it is exposed to oxygen and should not undergo fermentation.

When Performing the O/F Test, One Tube Is Covered with Mineral