Transport in plants

Plants need to move water and other molecules through their stems.

A student uses this apparatus to estimate water uptake by a leafy shoot.

State the name of this apparatus.

Describe how the student can use this apparatus to find the rate that the gas bubble moves in cm/minute.

To find this estimate of water uptake in 10 minutes, the student took measurements for 60 minutes and divided their answer by 6.

Suggest why they did this.

The student wanted to check the reproducibility of their results.

State one way that they could do this.

The student wants to extend their experiment to investigate the effect of leaf area on the rate of water uptake.

Suggest how the student could measure the area of a leaf.

The student then investigates the number of stomata on the upper and the lower surfaces of one of the leaves from the shoot.

The table shows their results.

Calculate the mean number of stomata on the upper surface.

Mean number of stomata =........ per mm²

The mean number of stomata on the lower surface of the student’s leaf is 49 per mm². (i)

Use this value and the graph to find the transpiration rate for this plant.

Transpiration rate =........ arbitrary units

Suggest two conclusions that can be made from the trends shown in this graph.

Plants need to move water and other molecules through their stems.

A student uses this apparatus to estimate water uptake by a leafy shoot.

State the name of this apparatus.

Describe how the student can use this apparatus to find the rate that the gas bubble moves in cm/minute.

To find this estimate of water uptake in 10 minutes, the student took measurements for 60 minutes and divided their answer by 6.

Suggest why they did this.

The student wanted to check the reproducibility of their results.

State one way that they could do this.

The student wants to extend their experiment to investigate the effect of leaf area on the rate of water uptake.

Suggest how the student could measure the area of a leaf.

The student then investigates the number of stomata on the upper and the lower surfaces of one of the leaves from the shoot.

The table shows their results.

Calculate the mean number of stomata on the upper surface.

Mean number of stomata =........ per mm²

The mean number of stomata on the lower surface of the student’s leaf is 49 per mm². (i)

Use this value and the graph to find the transpiration rate for this plant.

Transpiration rate =........ arbitrary units

Suggest two conclusions that can be made from the trends shown in this graph.

The arrows show direction of movement inside the vessels.

Give two reasons why Fig. 15.2 shows phloem vessels.

Compare the type of substances transported in xylem and phloem vessels.

Explain how the transport of substances through xylem changes on a warm day compared with a cold day.

Fig. 11.1 and Fig. 11.2 show two different transport vessels in plants.

Fig. 11.1
Fig. 11.2

Xylem vessels
Phloem vessels

The arrows show direction of movement inside the vessels.

Give two reasons why Fig. 11.2 shows phloem vessels.

Compare the type of substances transported in xylem and phloem vessels.

Explain how the transport of substances through xylem changes on a warm day compared with a cold day.

The photograph shows a cross section of a root seen under a light microscope.

Transport cell

Complete each sentence about root hair cells. Use words from the list.

active transport glucose
mineral ions

osmosis
surface area
volume

Root hair cells take in water and........ from the soil.

Water is taken in by the process of........

For more efficient uptake, the root hair cell has a large........

Water moves from the root hair cells into the transport cells of the roots.

Describe how water travels to the leaves of the plant from the roots.

A student investigates the effect of air movement on the rate of water uptake using a plant cutting.

The diagram shows the apparatus they use.

Electric fan

This is the method they follow:

• Measure the level of water in the calibrated pipette.

• Switch on the fan and record the level of water again after 25 minutes.

• Repeat investigation with the fan switched off.

The table shows their results.

Describe the effect of air movement on water uptake.

Calculate the rate of water uptake when the fan is switched off.

Give your answer to 1 significant figure.

Rate of water uptake =........ cm³ / min

Suggest one way the student could now investigate the effect of light intensity on water uptake.

Which sentence describes one function of translocation?

A The transport of mineral ions from the leaf to the meristem.

B The transport of mineral ions from the meristem to the leaf.

C The transport of sugars from the leaf to the meristem.

D The transport of sugars from the meristem to the leaf.

A student investigates the environmental factors that affect water uptake by plants.

The diagram shows the apparatus they use.

What is the name of the apparatus shown in the diagram?

gas syringe funnel potometer water bath

Describe how the student would use the air bubble to measure water uptake.

Write down two environmental factors that increase the rate of water uptake by plants.

When they set up the apparatus, the student cut the shoot under water.

Suggest why.

Most of the water taken in by the plant is lost in transpiration.

Complete the table to compare the processes of transpiration and translocation.

Water is transported in xylem vessels.

Write down one way xylem vessels are adapted to this function.

Why was each pot covered with a clear plastic bag?

What would be the effect on the results if the pots were not covered?

The student has not tried to reduce the effects of random error.

Suggest how they should have done this.

Write down the independent variable and dependent variable for this investigation.

Independent variable........

Dependent variable........

Plant C has 2 leaves. It had a starting mass of 138 g. After 24 hours the mass of plant C was 131 g.

Calculate the percentage decrease in mass for plant C.

Give your answer to 2 significant figures.

* The percentage decrease in mass for:

• plant A (6 leaves) is 16.2%

• plant B (4 leaves) is 8.9%.

Explain the difference in the percentage decrease for plant A and plant B.

Use ideas about transpiration in your answer.

Which statement describes how water is lost from the leaf?

A Diffusion of water from cells followed by diffusion through the stomata.

B Diffusion of water from cells followed by evaporation through the stomata.

C Evaporation of water from cells followed by diffusion through the stomata.

D Evaporation of water from cells followed by evaporation through the stomata.

Which substances are transported in the phloem vessels?

A Sucrose only

B Water and mineral ions

C Water and sucrose

D Water only

Translocation is a process that occurs in plants.

Which row describes translocation?