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Biology · Respiration · Respirometer
Comparing rate of respiration in different organisms
The organism sits in a sealed tube with KOH (absorbs CO₂). As it respires, O₂ is consumed and pressure drops. The manometer fluid moves toward the organism. Distance moved ÷ time → rate of O₂ uptake.
t = 0.00 min · d = 0.0 mm
Results table
| Organism | d (mm) | μL O₂ /g /min |
|---|---|---|
| Germinating peas | — | — |
| Maggots | — | — |
| Woodlice | — | — |
| Boiled peas | — | — |
Exam-style questions
1. What is the purpose of the KOH in each chamber?
2. Why is a SECOND identical apparatus set up alongside?
3. Why is rate calculated PER GRAM of tissue?
4. At 30 °C instead of 20 °C, you would expect the rate to: