1 markThe diagram below shows a potted plant and the same plant 48 hours later.
What has caused the plant’s appearance to change?
Water loss by translocation is greater than water uptake.
Water evaporating from the leaves by translocation.
Water loss by transpiration is greater than water uptake.
Water loss from the leaves by osmosis.
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1 markWhich of the following is a correct explanation of the process of translocation in a plant?
The movement of mineral ions through the xylem of a plant.
The movement of sucrose and amino acids through the phloem from a source to a sink.
The one-way movement of sucrose and amino acids through the phloem.
The movement of sucrose and amino acids through the phloem from a sink to a source.
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1 markThe diagram shows a simplified water cycle.
Which of the processes listed below would be involved in the loss of water from the tree?
Respiration
Translocation
Photosynthesis
Evaporation
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1 markA potometer can be used to measure the rate that a piece of plant transpires under various conditions.
Part of a potometer is shown in the diagram below.
Which statement, relating to how a potometer works, is false?
A potometer uses the transpiration stream to produce movement of an air bubble that can be measured.
In a potometer, an air bubble moves away from the piece of plant tissue that is under investigation.
In order to determine the rate of transpiration, the movement of the bubble must be measured alongside the time taken.
The leaves of the plant in the potometer must be dry during the experiment.
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1 markThe diagram below shows part of the trunk of a small dicotyledonous tree with a ring of bark removed.
Removing the ring of bark removes one type of transport tissue but leaves the other type intact.
What effect does removing the bark have on the two branches?
| upper branch | lower branch | |||
| leaves | growth | leaves |
growth |
|
| A | normal | normal | normal | reduced |
| B | wilted | normal | wilted | normal |
| C | wilted | reduced | normal | normal |
| D | normal | reduced | wilted | reduced |
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1 markThe xylem has specific adaptations to allow it to transport water and mineral ions from the roots of a plant to the leaves as a result of transpiration.
Which processes produce the adaptations in xylem vessels to allow the continuous flow of water?
|
cell walls break down between adjacent cells |
cytoplasm and organelles removed from each cell |
|
|
A |
✘ | ✘ |
|
B |
✓ | ✓ |
|
C |
✘ | ✓ |
|
D |
✓ | ✘ |
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1 markWhich of the following graphs shows most clearly what would happen to the rate of transpiration as humidity decreases?
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1 markThe diagram below shows two shoots at the start of an experiment set up by a group of students.
What are the most likely readings on the spring balances after four days?
| Spring balance readings / g | ||
| shoot A | shoot B | |
| A | 40 | 40 |
| B | 40 | 34 |
| C | 34 | 40 |
| D | 34 | 34 |
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1 markThe table below shows some characteristics of four different plants.
The plants are growing in the same environmental conditions.
Which plant will have the lowest rate of transpiration?
|
number of leaves on plant |
average surface area of one leaf / cm2 |
average density of stomata on leaves / stomata per mm2 |
average diameter of one stoma / µm |
|
| A | 36 | 53 | 276 | 19 |
| B | 21 | 51 | 247 | 18 |
| C | 24 | 45 | 249 | 15 |
| D | 17 | 40 | 151 | 16 |
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1 markWhich row of the table below shows substances transported through the phloem and xylem, and the direction of transport, correctly?
| phloem | direction of transport | xylem | direction of transport | |
| A | sucrose and amino acids | bi-directional (up and down) | water and mineral ions | bi-directional (up and down) |
| B | sucrose | unidirectional (up) | water and mineral ions | bi-directional (up and down) |
| C | sucrose | bi-directional (up and down) | water | unidirectional (up) |
| D | sucrose and amino acids | unidirectional (up) | water | unidirectional (up) |
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1 markWhich of the following processes is/are involved in the loss of water from the leaves of plants?
1 and 3
1 only
4 only
1 and 4
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1 markA student collected some of the solution from the phloem in the stem of a plant.
Which of the following would be present in the liquid?
Glucose
Starch
Amino acids
Cellulose
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1 markA decrease in which of the following factors would normally cause the transpiration rate to increase?
Stomatal density
Light intensity
Temperature
Humidity
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1 markWhich environmental factor is most likely to be responsible for a plant to wilt?
A decrease in light intensity.
An increase in humidity.
A decrease in the amount of available water.
A decrease in wind speed.
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The diagram shows the pathway of water molecules through part of a leaf, seen under a microscope, in a transverse section.
Where does water evaporate?
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Which row shows how the rate of transpiration changes when conditions in the atmosphere change?
| reduced wind | increased humidity | |
| A | decreases | decreases |
| B | decreases | increases |
| C | increases | decreases |
| D | increases | increases |
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