How Roots are Adapted For Water and Mineral Ion Uptake
Laura Armstrong & Joe Wolfensohn
Teachers
Recall Questions
This topic requires prior knowledge of plant cell specialisation and osmosis to understand the role of root hair cells in uptake.
What is differentiation?
The process by which cells become specialised
What type of specialised cell is found in roots?
Root hair cells
What plant sub-cellular structure is absent from a root hair cell?
Chloroplasts
Topic Explainer Video
Check out this @JoeDoesBiology video that explains how roots are adapted for water and mineral ion uptake, then read the study notes. Once you’ve gone through them, don’t forget to try the practice questions!
Adaptations of Roots for Absorption
What Are Roots For?
Roots anchor the plant in the soil and absorb water and minerals needed for photosynthesis and growth.
What Do Roots Absorb?
- Water – needed for photosynthesis, transpiration and to maintain the shape of the cells.
- Mineral ions – such as nitrates (for making proteins) and magnesium (for making chlorophyll).
Adaptations of Roots (especially Root Hair Cells)
|
Adaptation |
Explanation |
|
Root hair cells |
Specialised cells with a long extension to increase surface area. |
|
Large surface area |
Maximises contact with soil for more efficient absorption. |
|
Thin cell wall |
Shortens diffusion distance. |
|
No chloroplasts |
Not needed underground – saves energy and space. |
|
Many mitochondria |
Provide energy for active transport of mineral ions. |
|
Steep concentration gradient |
Maintained by continuous transport of minerals into the xylem. |
How Substances Are Absorbed
- Water:
- Moves into root hair cells by osmosis. See separate study note on this topic.
- Moves into root hair cells by osmosis. See separate study note on this topic.
- Minerals:
- Absorbed by active transport – against the concentration gradient using energy released from respiration. See separate study note on this topic.
Key Terms
- Root hair cell – a specialised plant cell adapted for absorption.
- Osmosis – movement of water from a dilute to a concentrated solution, across a partially permeable membrane.
- Active transport – energy-requiring process to move substances against their concentration gradient.
- Surface area – area over which absorption can occur.
No answer provided.
Exam Tip
- Link the adaptations of the roots to the factors that affect the rate of diffusion.
No answer provided.
Practice Question
Explain why root hair cells have many mitochondria. (3 marks)
Model Answer:
- Mitochondria release energy from respiration.
- Energy is used for active transport.
- To absorb mineral ions against their concentration gradient.
More Practice
Try to answer these practice questions from the TikTok videos on your own, then watch the videos to see how well you did!