Transport in Plants
448 questions· page 1 of 45
Which row correctly describes the role of growing leaves as sources or sinks for amino acids and sucrose?
Options
| amino acids | sucrose | |
|---|---|---|
| A | leaves act as sinks only | leaves can act as sources or sinks |
| B | leaves act as sinks only | leaves act as sources only |
| C | leaves can act as sources or sinks | leaves act as sources only |
| D | leaves can act as sources or sinks | leaves can act as sources or sinks |
Which changes occur as amino acids are moved into phloem sieve tubes at a source?
Options
| change in water potential in phloem sieve tubes | change in volume of sap in phloem sieve tubes | |
|---|---|---|
| A | decreases | decreases |
| B | decreases | increases |
| C | increases | decreases |
| D | increases | increases |
The photomicrograph shows a section of the stem of a plant.
Which statements could describe Q?
1 The cell wall contains pits.
2 The cell wall contains cellulose and also lignin.
3 It is connected to adjacent cells via plasmodesmata.
Options
A 1 and 2
B 1 and 3
C 1 only
D 2 and 3
Three samples of liquid were taken from different locations in a plant and tested to measure the concentration of four solutes. The results are shown.
| sample | concentration of solute / | |||
|---|---|---|---|---|
| sucrose | nitrate ions | amino acids | magnesium ions | |
| 1 | 652 | 0.14 | 41 | 3.4 |
| 2 | 0.12 | 7.1 | 7.2 | 1.1 |
| 3 | 433 | 0.6 | 68 | 3.7 |
Which samples have been taken from phloem sieve tube elements?
Options
A 1, 2 and 3
B 1 and 2 only
C 1 and 3 only
D 2 and 3 only
A heated band was wrapped around the stem of a plant at a height of above the ground and left for 10 minutes.
How will heating a small section of the stem to affect the transport of phloem sap and xylem sap between the roots and leaves?
Options
| transport of phloem sap | transport of xylem sap | |
|---|---|---|
| A | ✓ | ✓ |
| B | ✓ | ✗ |
| C | ✗ | ✓ |
| D | ✗ | ✗ |
key
✓ = transport continues
✗ = transport stops
Which row is correct for transpiration?
Options
| definition of transpiration | comparison of water potential | |
|---|---|---|
| A | evaporation of water from leaf surfaces | higher inside air spaces in the leaf than the air outside |
| B | evaporation of water from leaf surfaces | lower inside air spaces in the leaf than the air outside |
| C | loss of water vapour from leaves | lower inside air spaces in the leaf than the air outside |
| D | loss of water vapour from leaves | higher inside air spaces in the leaf than the air outside |
Which features of companion cells and xylem vessel elements make them suitable for their function?
Options
| companion cells | xylem vessel elements | |
|---|---|---|
| A | transport contents of cell in one direction only | lignified walls provide support |
| B | cellulose walls provide support | nuclei allow cell division |
| C | nuclei allow cell division | gaps between cells allow rapid transport |
| D | numerous mitochondria supply energy | absence of cytoplasm allows mass flow |
The diagram shows some root cells.
Which statement is correct for the pathway shown by the arrows?
Options
A Water will be blocked by a band of suberin.
B Water will move through the Casparian strip.
C Water will pass easily through the root endodermis.
D Water will pass through plasmodesmata.
The graph shows the diameter of a tree trunk at different times.
Which statement is correct?
Options
A J shows the expansion of the trunk as water fills the xylem during transpiration.
B K shows a reduction in diameter of the trunk as water is lost from the phloem due to translocation.
C K shows a reduction in diameter of the trunk due to water held in tension in the xylem.
D L shows the expansion of the trunk as the phloem tissue acts as a sink at night.
The plan diagrams of transverse sections of two plant organs are shown. These are not drawn to scale.
Which tissues contain proton pumps?
Options
A Q and S
B Q and T
C R and S
D R and T