B1.5 specialisation in plant cells Flashcards
Where are root hair cells found?
Close to the tips of growing roots
Where are phloem cells found?
In the stem of the plant
Where are xylem cells found?
Towards the centre of the stem
Where are photosynthetic cells (palisade cells) found?
On the top surface of a leaf
What is the function of a root hair cell?
They absorb minerals and water from the soil.
What is the function of a phloem cell?
They carry food made by photosynthesis around the body of the plant.
What is the function of a xylem cell?
They transport water and mineral ions around the plant
What is the function of a photosynthetic cell (palisade cell)?
To carry out photosynthesis
What adaptations do root hair cells have?
- large surface area to absorb lots of water
- thin cell wall to allow water to pass through easily
- large permanent vacuole that speeds to the movement of water by osmosis from the soil across the root hair cell
- Many mitochondria that transfer the energy needed for the active transport of mineral ions into the root hair cells
What adaptations do phloem cells have?
- cell walls form special sieve plates to allow water-carrying food to freely move throughout the stem.
- the companion cells have lots of mitochondria to release energy for the movement of food.
What adaptations do Xylem cells have?
- spirals of lignin to strengthen the cell and support the plant
- long hollow tube - easy movement of water and mineral ions.
What adaptations do Photosynthetic cells (palisade cells) have?
- tall and has a large surface area to absorb maximum sunlight
- packed with chloroplast to absorb sunlight
- large permanent vacuole that keeps the cell rigid as a result of osmosis. Lots of these rigid cells are arranged together to form photosynthetic tissue that helps support the stem
State one adaptation for each of the following specialised plant cells.
Describe how this adaptation helps the cell carry out its function:
a root hair cell
b xylem cell
c phloem cell
d photosynthetic cell
• increased surface area – to promote water uptake
• cells die forming long hollow tubes – to allow water and mineral ions to move easily through them
• cell walls break down to form sieve plates – to enable water and dissolved food to pass through
• chloroplasts – contain chlorophyll to trap light needed for photosynthesis
Suggest why a cell within the trunk of a tree cannot carry out photosynthesis
Cell not exposed to sunlight and therefore not adapted to photosynthesise (not photosynthetic)
Describe the features you would look for to decide on the unknown function of a specialised cell
• chloroplasts – presence indicates whether cell is photosynthetic
• large vacuole – presence indicates role in osmosis/rigid support
• lignin spirals – presence indicates strengthening and transport of
water
