Chapter 8
1.
Look at the diagram of the root hair in the soil.
(a) Name the parts labelled A to F.
A
B
C
D
E
F
[6]
(b) Explain how water gets into the root hair cell from the soil.
[2]
(c) Give two other functions of root hair cells.
[2]
2.
In plant transport, the part of the plant where a substance begins its journey is called a source.
The part where it ends its journey is a sink.
(a) Define the term translocation.
[1]
(b) What substances are translocated in the phloem?
[1]
(c) What are the materials transported in the phloem used for?
[1]
3.
The diagrams show transverse sections of A root, B stem and C leaf.
(a) Shade the areas that represent the positions of xylem and phloem in A, B and C.
[3]
(b) Complete the table below to compare the functions of xylem and phloem. The term sap
refers to the liquid transported in these two tissue.
Feature
Composition of the sap
Direction of flow in the stem
Destinations
Phloem
Xylem
[6]
(c) Describe how you would discover the pathway taken by water as it travels through the parts
of the plant that are above ground.
[3]
4.
A photometer was used to measure water uptake by a leafy shoot.
A
B
C
D
E
Conditions
Cool, humid air in daylight
Cool, dry air in daylight
Warm, dry air in daylight
Warm, humid air in daylight
Warm, humid air at night
Time taken for the water to move 100 mm / min
2
6
1
3
60
(a) Calculate the rate of water movement in mm/min for each of the conditions, A to E, and
present your answer in a table.
[3]
(b) Draw a bar chart to show the effect of the five conditions on the rate of water movement.
[5]
(c) From the results, state three environmental conditions that affect the rate of water
movement through the plant.
[3]
(d) State two ways in which the air around the shoot would be affected if it was covered with a
transparent plastic bag.
[2]
5.
A leafy shoot was cut from a plant and laced into a photometer which was placed on a balance.
The table shows the rate of water uptake and the rate of transpiration by the leafy shoot during
a hot, dry day.
Time / h
Midnight
0300
0600
0900
1200
1500
1800
2100
Midnight
Rate of water loss / gram per hour
4
6
12
18
24
22
18
8
6
Rate of water absorption / gram per hour
7
9
12
14
17
19
20
14
10
(a) Plot a graph to show the data in the table.
[5]
(b) Calculate the percentage change in the rate of water loss between 0600 hours and 1200
hours. Show your working.
[2]
(c) Describe the changes in water loss and water absorption over the 24-hour period.
[4]
(d) Explain how water moves from the cut end to the stem to the atmosphere.
[4]
6.
Using the apparatus shown below, a student set out to investigate the factors that influence
water uptake by a plant.
A series of experiments he obtained the following results.
Environmental condition
Time taken for bubble to Rae of bubble movement /
move 10 cm / min
cm per minute
1, High light intensity
5
2, High humidity (plant
16
enclosed in clear plastic bag)
3, Wind (electric fan blowing
1
over plant surface)
4, Dark and windy
17
5, Dark and low humidity
25
(a) Calculate the rate at which the bubble moves.
[5]
(b) Plot these results in the form of a bar chart.
[5]
(c) Plants require light for photosynthesis, and ‘anticipate’ the need for carbon dioxide uptake
during photosynthesis by opening their stomata under appropriate conditions. Does this
help to explain the results of the first experiment? Explain your answer.
[2]
(d) Water is lost from leaves by evaporation and diffusion if the stomata are open, and a suitable
water potential gradient exists. Use this information to explain the results of experiment 2
and 5.
[3]
(e) How can you explain the results of experiments 3 and 4?
[2]
7.
Four leaves were removed from the same plant. Petroleum jelly (a waterproofing agent) was
spread onto some of the leaves, as follows:
Leaf A: on both surface
Leaf B: on the lower surface only
Leaf C: on the upper surface only
Leaf D: none applied
Each leaf was then placed in a separate beaker, as shown in the diagram.
Each beaker was weighed at intervals. The results are shown in the graph.
(a) Give evidence from the graph in answering the following questions.
(i)
Which surface (upper or lower) loses water most rapidly?
[1]
(ii) Is water lost from both surfaces of the leaf?
[1]
(b) The diagrams below show the appearance of each surface of the leaf as seen through a
microscope.
(i)
Name space X and cell Y.
[2]
(ii) Use the information in the diagram to explain why the results are different for leaves B
and C.
[2]
8.
The diagrams show the underside of two leaves.
(a) Name the structures labelled A.
(b) Make a labelled drawing of a side view of one of these structures.
(c) Water can be lost from a leaf through these structures. The water on the surface of spongy
mesophyll cells changes to water vapour, and then moves out of the leaf down a
concentration gradient.
(i)
Name the process in which water changes from liquid to vapour.
[1]
(ii) Name the process by which the molecules of water vapour move down a concentration
gradient.
[1]
(iii) Suggest one advantage and one disadvantage of this process to the plant.
[2]
(d) The view of leaf underside cover 1 mm2. Each of the leaves measured 5 cm x 2 cm. Calculate
the total number of the structures A on each of the leaves. Show your working.
Leaf
X
Y
Number of structures A in 1 mm2
Total numbers of structures A on leaf
[4]
(e) Which of the leaves is better adapted to living in dry, hot conditions? Explain your answer.
[2]
(f)
Give two other features of leaves adapted to life in dry, hot conditions.
[2]
9.
The diagram below shows a transverse section through an Ammophila leaf. This plant has very
long roots. The diagram on the right shows a cactus plant. Both plants live in very dry conditions.
(a) Suggest how each of the following adaptations would enable the named plant to survive in
very dry conditions.
(i)
Ammophila
1)
rolled leaves with stomata on the inside of the leaf
[2]
2)
thich way cuticle on the outside of the leaf
[1]
(ii) Cactus
1)
very long roots
[1]
2)
fleshy green stem
[2]
(b) Suggest why having only a few, very small leaves could be a disadvantage to a plant.
[2]
(c) Water is involved in a number of processes in plants. Complete the table by naming the
process described and stating one variable that, if increased, would speed up the process.
Description
of Name of process
process
Absorption of water
from the soil
Using water to form
glucose
Movement of water
vapour out of leaves
Variable that, if increased, would
speed up the process
[6]
10. Think carefully about the following statements. Write T if the statement is true and F if the
statement is false.
Statement
The transport system in plants is an open system.
Only xylem elements have cell walls.
Both xylem and phloem elements are non-living.
Xylem and phloem elements are made up of very long cells stretching from the
roots to the leaves.
(e) Xylem and phloem elements provide mechanical support for the plant.
(f) Companion cells in the vascular bundle help produce more xylem and phloem
cells.
(g) Water can only enter the roots by the root hairs.
(h) Root pressure pushes water into the root hairs.
(i)
Root pressure forces water to climb up the narrow vessels of xylem.
(j)
Roots use active transport to absorb mineral salts from the soil.
(k) Evaporation of water from the leaves increases the strength of the cohesive
force which results in more water molecules being pulled up the xylem.
(l)
The rate of transpiration is affected only by the concentration of water
molecules in the air around the leaves.
(m) Food manufacturers by the leaves will only move towards the vigorously
growing parts.
(n) The rate of translocation depends on the sugar concentration in the leaves.
(o) The rate of translocation is linked to the rate of the transpiration.
(p) Transpiration only takes place during the day but translocation takes place all
the time.
(a)
(b)
(c)
(d)
T/F