Question

A student poured a solution of bromthymol blue indicator into three test tubes. Then, he placed an aquatic plant in two of the test tubes. He placed a stopper on each test tube and placed them all in the dark for 24 hours. Bromthymol blue turns from blue to yellow in the presence of CO2. Which process(es) would you expect the organisms in the test tubes to carry out - cellular respiration, photosynthesis, or both? When would you expect each process to occur?

Answer 1

The organisms in the test tubes with aquatic plants would carry out both cellular respiration and photosynthesis. During the daylight hours, they would undergo photosynthesis, producing glucose and oxygen. During the dark hours, they would undergo cellular respiration, producing carbon dioxide and water.

Step-by-step explanation:

In the test tubes with aquatic plants, the organisms would carry out both cellular respiration and photosynthesis.

During the daylight hours, the organisms would undergo photosynthesis. They would take in carbon dioxide and water and use sunlight to produce glucose and oxygen. This would cause the bromthymol blue indicator to turn blue since there would be a lower concentration of carbon dioxide.

During the dark hours, the organisms would undergo cellular respiration. They would take in glucose and oxygen and produce carbon dioxide and water. This would cause the bromthymol blue indicator to turn yellow since there would be a higher concentration of carbon dioxide.