Single answerDifficulty 3/5 · ChallengingOlympiadRepresenting dataStatistical analysis
Potato cores in sucrose
Topic: Tonicity & water potential
A student cut identical cores from one potato, weighed them, and left three cores in each of six sucrose solutions in open beakers at 22 °C. After 24 hours she blotted and reweighed them. Sucrose does not cross potato cell membranes during the experiment.
Experimental setup
- Question
- What is the water potential of the potato tissue?
- Independent variable
- Sucrose concentration of the bathing solution (M)
- Dependent variable
- Percentage change in core mass after 24 h
- Kept constant
- Same potato · Core size and shape · Temperature (22 °C) · Time (24 h) · Blotting method
- Groups
- Control: 0.0 M (distilled water)
- Treatments: 0.2, 0.4, 0.6, 0.8 and 1.0 M sucrose
Data
| Sucrose (M) | Change in mass (%) |
|---|---|
| 0.0 | +18.5 |
| 0.2 | +4.0 |
| 0.4 | −4.2 |
| 0.6 | −11.6 |
| 0.8 | −17.9 |
| 1.0 | −21.3 |
Use the data and ψs = −iCRT (R = 0.0831 L·bar/mol·K) to estimate the water potential of the potato cells.
Answer every part to submit.