In a respirometer experiment measuring cellular respiration, how should the movement of the gas bubble be interpreted?

• A. The bubble's movement reflects the rate of glucose uptake by the organism.
• B. The distance the bubble moves indicates the amount of carbon dioxide produced by the organism.
• C. The bubble's movement shows the change in temperature inside the respirometer.
• D. The distance the bubble moves indicates the volume of oxygen consumed by the organism.

Answer: (D)

Verified step by step guidance

1. Understand the purpose of a respirometer: A respirometer is a device used to measure the rate of cellular respiration by tracking the consumption of oxygen. It typically consists of a sealed chamber containing the organism, a gas-tight syringe or pipette, and a liquid or gas bubble that moves in response to changes in gas volume.
2. Recognize the role of oxygen in cellular respiration: During cellular respiration, organisms consume oxygen to break down glucose and produce energy in the form of ATP. The oxygen consumption is directly proportional to the rate of cellular respiration.
3. Interpret the movement of the gas bubble: The movement of the bubble in the respirometer is caused by the reduction in gas volume inside the chamber as oxygen is consumed by the organism. This movement is not related to glucose uptake, carbon dioxide production, or temperature changes.
4. Relate the bubble's movement to oxygen consumption: The distance the bubble moves along the scale of the respirometer indicates the volume of oxygen consumed over a specific period of time. This measurement can be used to calculate the rate of cellular respiration.
5. Conclude the correct interpretation: Based on the principles of how a respirometer works, the correct interpretation is that the distance the bubble moves reflects the volume of oxygen consumed by the organism during cellular respiration.