A student investigated water loss from leafy shoots.
The student placed four similar leafy shoots in separate tubes of water. A layer of oil was added to the surface of the water in each tube.
Each tube was placed in a different condition. The student measured the mass of each tube at the start and after 4 hours.
The Table shows the results.
Table
| Condition | Mass at start in g\text{g}g | Mass after 4 hours in g\text{g}g |
|---|---|---|
| still air at 20 ∘C20\ ^{\circ}\text{C}20 ∘C in the light | 54.6 | 53.4 |
| moving air at 20 ∘C20\ ^{\circ}\text{C}20 ∘C in the light | 55.0 | 52.6 |
| still air at 30 ∘C30\ ^{\circ}\text{C}30 ∘C in the light | 54.2 | 52.2 |
| still air at 20 ∘C20\ ^{\circ}\text{C}20 ∘C in the dark | 54.8 | 54.4 |
Explain why a layer of oil was added to the surface of the water.
Calculate the rate of mass loss for the shoot in moving air, in g\text{g}g per hour.
Explain why the shoot in the dark lost the least mass.
The student concluded:
"Air movement has a bigger effect on water loss than temperature."
Comment on whether the results support this conclusion.
43 exam-style questions on Edexcel GCSE Biology 6.2 Transport in plants, covering 6.2.1 Root hair cell adaptations, 6.2.2 Structure of xylem and phloem, 6.2.3 Transpiration and stomata, 6.2.4 Translocation of sucrose, 6.2.5 Leaf structure for photosynthesis, 6.2.6 Environmental factors on water uptake, 6.2.7 Rate calculations for transpiration, and 6.2.8 Plant adaptations to extreme environments. Each one has a worked solution and a mark scheme showing where the marks go.