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B3 1.5c – Student worksheet
Exchanges
1
Choose the correct words to complete the sentences to describe how water enters root hair
cells. (6 marks)
(diffuse, down, higher, osmosis, partially permeable)
Root hairs absorb water by _____. The concentration of water in the soil is _____ than the
concentration of water inside the root hair cell. This causes water to _____ through the _____
membrane into the cell. This increases the amount of water in the outer root hair cells. Water
moves by _____ from the root hair cells into other root cells _____ a concentration gradient.
2
The advice below appears in a gardening book. Use your knowledge of roots to explain the
reasons for this advice. (3 marks)
When you are moving a plant from one part of the garden to another, take great care not to
damage the roots. Leave as much soil around the roots as you can so that they do not get
damaged. When you have put the plant into its new position, give it plenty of water and
continue to water it well for the next few weeks.
3
Choose the correct words to complete the sentences.
(air, diffuses, evaporates, film, saturated, stomata (x2), transpiration, upper, water (x2), vapour)
Plants lose _____ from the surface of their leaves continuously. This loss of water is called
_____. The cells lining the _____ spaces in the leaf are covered with a thin _____ of water.
As this water _____, the air spaces become _____ with water vapour. The water vapour
_____ through the air spaces and then out through the _____. Most of the water _____ lost
by transpiration is through _____. A small amount of _____ is also lost through the _____
surface of leaves. (12 marks)
4
Match the terms to their meanings. (5 marks)
1 Stomata
A The loss of water vapour from the surface of the leaves.
2 Transpiration
B These provide a large surface area for leaf cells to absorb
carbon dioxide.
3 Guard cells
C This part of the leaf loses a small amount of water vapour.
4 Air spaces
D Tiny pores in the leaf through which most of the water
vapour is lost from a plant.
5 Upper surface
E These cells surround the stomata and control whether the
stoma is open or closed.
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