Question

A bacterium was grown in two test tubes filled with media rich in glucose. One tube was sealed to

produce anaerobic conditions, and the other was not. A third uninoculated, unsealed tube was used as a control. Glucose utilization by this bacterium causes acid production, which is indicated by a lightening of the media color. If the bacterium is able to produce ATP only by respiration, which
result do you expect to receive?

A) lightening of media in the unsealed tube only
B) lightening of media in all three tubes
C) lightening of media in the control tube only
D) lightening of media in the sealed and unsealed tubes only
E) lightening of media in the sealed tube only

Answer 1

A) lightening of media in the unsealed tube only

Lightening of the media would only occur in the unsealed tube, as the bacterium can produce ATP only by respiration, which requires oxygen.

Step-by-step explanation:

If the bacterium is able to produce ATP only by respiration, then we would expect to see lightening of the media only in the unsealed test tube, which is indicative of acid production from glucose utilization. Since respiration requires oxygen, anaerobic conditions (such as in the sealed tube) would not allow for respiration to occur, assuming the bacterium does not have the capability for anaerobic respiration or fermentation. Therefore, the correct answer would be A) lightening of media in the unsealed tube only.