Describe how water moves from the soil into the xylem of a plant root.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Water is absorbed by root hair cells by osmosis.
Root hair cells increase the surface area for absorption.
Water moves from root hair cells into the cortex cells by osmosis.
Water then enters and travels up the xylem vessel.
Root hair cells increase the surface area for absorption.
Water moves from root hair cells into the cortex cells by osmosis.
Water then enters and travels up the xylem vessel.
Examiner tips
- Use the word "osmosis" when describing absorption. Mention root hairs as the first point of contact. Show the sequence: root hair → cortex → xylem. Keep the answer concise and use correct plant anatomy terms.
Common mistakes
- Forgetting to mention osmosis. Omitting root hairs or the cortex. Using vague terms like "water flows" without specifying the mechanism. Writing in the wrong order or adding unnecessary detail.
Mark scheme (4 marks)
- Water is absorbed by root hair cells by osmosis
- Root hair cells increase the surface area for absorption
- Water moves from root hair cells into the cortex cells by osmosis
- Water then enters and travels up the xylem vessel
Key terms in this question
Related
- All Cambridge International IGCSE Biology (0610) revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →