Question

an experiment to measure the rate of respiration in crickets and mice at 10°c and 25°c was performed using a respirometer, an apparatus that measures changes in gas volume. respiration was measured in ml of o₂ consumed per gram of organism over several five - minute trials, and the following data were obtained. during aerobic cellular respiration, oxygen gas is consumed at the same rate as carbon dioxide gas is produced. in order to provide accurate volumetric measurements of oxygen gas consumption, the experimental setup should include which of the following? a valve to release excess water a substance that removes carbon dioxide gas a plant to produce oxygen a glucose reserve

Explanation:

• Option A: A valve to release excess water is not relevant to measuring oxygen consumption accurately as it doesn't address the issue of gas exchange (oxygen consumption and carbon dioxide production) in the context of the experiment.
• Option B: Since oxygen is consumed at the same rate as carbon dioxide is produced during aerobic respiration, if we want to measure oxygen consumption accurately, we need to remove carbon dioxide. This is because if carbon dioxide is not removed, it will contribute to the gas volume in the respirometer, and we won't be able to accurately isolate the volume change due to oxygen consumption.
• Option C: A plant to produce oxygen is not useful. The experiment is about measuring the respiration (oxygen consumption) of crickets and mice. Adding a plant that produces oxygen would introduce an additional variable (oxygen production) that would confound the measurement of oxygen consumption by the test organisms.
• Option D: A glucose reserve is not relevant to volumetric measurements of oxygen consumption. Glucose is a substrate for respiration, but having a glucose reserve doesn't help in accurately measuring the volume of oxygen consumed as it doesn't address the gas - volume relationship (removal of carbon dioxide) in the respirometer.

Answer:

B. A substance that removes carbon dioxide gas