Explain why root hair cells are well adapted for absorbing water and mineral ions from the soil.

Eduqas GCSE Biology — 1.5.1 Plant structure and function · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Root hair cells have a very large surface area relative to their volume, which increases the rate of absorption and allows more water and mineral ions to be taken up from the soil.
Water enters the root hair cells by osmosis, moving down a water potential gradient.
Mineral ions are absorbed by active transport, which requires energy (ATP).

Examiner tips

Mention large surface area and its effect on absorption rate; include osmosis for water and active transport for ions; use correct terminology.
Use concise, exam‑style sentences; keep answer focused on the four points.

Common mistakes

Failing to state that water moves by osmosis; confusing diffusion with osmosis.
Not mentioning that ion uptake is active transport requiring energy; treating it as passive diffusion.

Mark scheme (4 marks)

Root hair cells have a large surface area
Which increases the rate of absorption / allows more water and mineral ions to be absorbed
Water moves into root hair cells by osmosis (down a water potential gradient)
Mineral ions are absorbed by active transport (requiring energy)

Key terms in this question

root hair cells · mineral ions