Explain how the process of transpiration is linked to the movement of water through xylem in a plant.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Transpiration is the evaporation of water from the leaves.
Water is lost through the stomata into the air.
This loss creates a pull (tension) and a lower water concentration in the leaf, which draws water upward through the xylem.
Xylem therefore transports water and dissolved minerals from the roots to the leaves.
Water is lost through the stomata into the air.
This loss creates a pull (tension) and a lower water concentration in the leaf, which draws water upward through the xylem.
Xylem therefore transports water and dissolved minerals from the roots to the leaves.
Examiner tips
- Use the word ‘transpiration’ first, then explain evaporation via stomata. Show the cause–effect chain: loss → tension → upward flow. Mention xylem’s role in transporting water and minerals.
- common_mistakes
- :
- Confusing transpiration with photosynthesis. Forgetting that the pull is due to tension, not pressure. Saying water moves from leaves to roots instead of roots to leaves.
Mark scheme (4 marks)
- Transpiration is the evaporation of water from the plant (leaves)
- Water evaporates / is lost through the stomata (into the air)
- This creates a 'pull' / tension / lower water concentration in the leaf, drawing water upwards through the xylem
- Xylem transports water and dissolved minerals from the roots to the leaves
Key terms in this question
Related
- Revision notes: Plant tissues, organs and systems →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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