A single-celled extension of an epidermis cell in the root, adapted for the efficient uptake of water (by osmosis) and mineral ions (by active transport).

How is a root hair cell adapted to absorb substances efficiently?

Its long, narrow extension greatly increases the surface area to volume ratio for absorption.

Why does water move into the root hair cell by osmosis?

The high proportion of dissolved minerals and sugars in its cytoplasm gives it a low water potential, so water moves in from the soil.

Why does increasing the surface area to volume ratio help the root hair cell?

It increases the rate of absorption of mineral ions by active transport (and of water by osmosis).

Where are root hairs found and how do they reach water?

They are single-celled extensions of root epidermis cells that grow between soil particles to absorb water and minerals from the soil.

Why is having a low water potential important for a root hair cell?

It ensures water moves from the soil into the cell by osmosis.

Transport tissue made of dead, hollow cells that carries water and dissolved mineral ions from the roots to the stem and leaves.

Living transport tissue that carries dissolved sugars (e.g. sucrose) and amino acids around the plant by translocation.

What is the function of xylem vessels?

To transport water and dissolved mineral ions from the roots to the stem and leaves.

Give three adaptations of xylem vessels.

No top and bottom walls between cells, forming continuous hollow tubes Cells are dead, with no organelles or cytoplasm, allowing free passage of water Outer walls are thickened with lignin to strengthen the tubes and support the plant

What is the function of phloem?

To transport dissolved sugars (e.g. sucrose) and amino acids around the plant.

Give three adaptations of phloem cells.

Made of living cells, supported by companion cells Cells joined end-to-end with holes (sieve plates) in the end walls so sugars and amino acids flow easily Very few subcellular structures to aid the flow of materials

Why are phloem cells described as living while xylem cells are not?

Phloem cells still retain some subcellular structures (and have companion cells), whereas xylem cells are dead and empty.

What are sieve plates and what do they do?

Holes in the end cell walls of phloem cells that allow sugars and amino acids to flow easily from one cell to the next.

GCSEScienceEdexcelCombined ScienceBiologyFlashcardsPlant Structures & their FunctionsPlant Structure

Plant Structure (Edexcel GCSE Combined Science: Biology): Flashcards

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Root hair cell

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Root hair cell
A single-celled extension of an epidermis cell in the root, adapted for the efficient uptake of water (by osmosis) and mineral ions (by active transport).
How is a root hair cell adapted to absorb substances efficiently?
Its long, narrow extension greatly increases the surface area to volume ratio for absorption.
How do root hair cells take up water?
By osmosis.
How do root hair cells take up mineral ions?
By active transport.
Why does water move into the root hair cell by osmosis?
The high proportion of dissolved minerals and sugars in its cytoplasm gives it a low water potential, so water moves in from the soil.
Why does increasing the surface area to volume ratio help the root hair cell?
It increases the rate of absorption of mineral ions by active transport (and of water by osmosis).
Where are root hairs found and how do they reach water?
They are single-celled extensions of root epidermis cells that grow between soil particles to absorb water and minerals from the soil.
Why is having a low water potential important for a root hair cell?
It ensures water moves from the soil into the cell by osmosis.
Root hair cells absorb water by and mineral ions by .
osmosis / active transport
The long shape of a root hair cell increases its area for absorption.
surface
Xylem
Transport tissue made of dead, hollow cells that carries water and dissolved mineral ions from the roots to the stem and leaves.
Phloem
Living transport tissue that carries dissolved sugars (e.g. sucrose) and amino acids around the plant by translocation.
What is the function of xylem vessels?
To transport water and dissolved mineral ions from the roots to the stem and leaves.
Give three adaptations of xylem vessels.
No top and bottom walls between cells, forming continuous hollow tubes
Cells are dead, with no organelles or cytoplasm, allowing free passage of water
Outer walls are thickened with lignin to strengthen the tubes and support the plant
What is the function of phloem?
To transport dissolved sugars (e.g. sucrose) and amino acids around the plant.
Give three adaptations of phloem cells.
Made of living cells, supported by companion cells
Cells joined end-to-end with holes (sieve plates) in the end walls so sugars and amino acids flow easily
Very few subcellular structures to aid the flow of materials
What substance thickens and strengthens xylem walls?
Lignin.
Why are phloem cells described as living while xylem cells are not?
Phloem cells still retain some subcellular structures (and have companion cells), whereas xylem cells are dead and empty.
What are sieve plates and what do they do?
Holes in the end cell walls of phloem cells that allow sugars and amino acids to flow easily from one cell to the next.
Xylem cell walls are thickened with to support the plant.
lignin
The holes in the end walls of phloem cells are called .
sieve plates

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