Transpiration

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 graphs show how the rate of water uptake in plants can change.

Which graph shows the correct effect of increased air movement on the rate of water uptake?

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.

The moisture content in soil affects the growth of plants.

A student investigates the moisture content of different soils.

This is the method they use:

• Measure the mass of each soil sample.

• Place the soil samples in a warm oven to dry for 4 hours.

• Measure the mass of each soil sample again.

The table shows their results.

Calculate the change in mass for each soil sample.

Write your answers in the table. Give all answers to the same number of decimal places.

The student uses the changes in mass to conclude that soil sample B had the highest percentage moisture content.

Suggest why the student cannot make a fair comparison between the samples.

Describe two ways the student could improve their investigation to get a valid conclusion.

Explain how low moisture content in soil affects transpiration in plants.

Moisture content is one abiotic factor that affects plants.

State two other abiotic factors that affect plant growth.

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.

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

The function of cell Q in the photograph is the uptake of water.

Explain how the structure of cell Q is adapted to this function.

Explain how the water moves through the root from cell Q to the xylem. Include ideas about water potential.

Explain the effect of turning on the electric fan upon the rate of water uptake shown in the table.

Suggest how the student could develop their investigation to explore the effect of changing the speed of air movement.

Plants and animals both have transport systems.

Fig. 15.1 shows cells found in the transport system of animals.

Fig. 15.1

Identify the type of cell shown in Fig. 15.1.

The transport system in animals is the circulatory system.

Describe the relationship between the circulatory system and the gas exchange system in the human body.

Phloem is part of the transport system in plants. Fig. 15.2 is a diagram of phloem sieve tubes.

Fig. 15.2

Explain how phloem sieve tubes are adapted to their function. Use Fig. 15.2.

Fig. 15.3 shows apparatus used to investigate the rate of water uptake in plants.

Fig. 15.3

Name the apparatus shown in Fig. 15.3.

The air-tight seal stops air getting into the water-filled tube.

Suggest why it is important to stop air getting into the tube.

The apparatus is set up and left for 10 minutes. The water level moved 8 mm.

Calculate the rate of water uptake in mm per second.

Give your answer to 2 significant figures.

Rate of water uptake =........ mm per second [3]

The investigation is repeated with an electric fan switched on next to the apparatus.

The rate of water uptake would increase / decrease / stay the same.

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.

Materials are cycled in the environment.

Complete these sentences about cycled materials.

Choose words from this list. You can use each word once, more than once or not at all.

decomposition condensation nutrition

photosynthesis translocation transpiration

Plants remove carbon from the atmosphere by the process of........

Plants return water to the atmosphere by the process of........

Nitrogen is returned to the soil by the process of........

Describe two ways that the water cycle is important to humans.

Abiotic and biotic factors can affect ecosystems.

Which two are biotic factors?

Tick (✓) two boxes.

The diagram shows a weather chart over 3 days.

The 24-hour rainfall for Sunday April 3 is ~1 mm.

Explain what is meant by the term ~1 mm.

Plants are an important part of ecosystems.

Which day would plants be most likely to take up water from the soil at the fastest rate?

Tick (✓) one box.

Explain your answer.

Water is cycled in nature.

Name one abiotic factor that affects water uptake by a plant.

Look at the diagram of the carbon cycle.

Which process is shown by arrow X in the diagram above?

Tick (✓) one box.

Which process releases carbon when organisms die ?

Tick (✓) one box.

The graph shows how carbon dioxide levels in the atmosphere have changed during the last 160 000 years.

Read this statement:

Carbon dioxide levels in the atmosphere are rising out of control.

What evidence is there in the graph for and against this statement?

Look at the section of the graph for the last 20 000 years.

What conclusions can be made about the release of carbon dioxide into the atmosphere and also its removal from the atmosphere during the last 20 000 years?

Describe how human activity has contributed to the trends in the graph and suggest how this activity could affect biodiversity.

The information in the box is part of a scientific journal report.

Growing crops with shiny leaves could cause an annual global cooling of over 0.1 °C.

This is almost 20% of the total global temperature increase since the Industrial Revolution.

Most crop plants have non-shiny leaves.

A few varieties of crop plants do have shiny leaves but they do not all produce high yields.

Explain how scientists could use selective breeding to help reduce global temperatures.

Water is cycled in nature.

Name one abiotic factor that affects water uptake by a plant.

Look at the diagram of the carbon cycle.

Which process is shown by arrow X in the diagram?

Tick (✓) one box.

Which process releases carbon when organisms die ?

Tick (✓) one box.

The graph shows how carbon dioxide levels in the atmosphere have changed during the last 160 000 years.

Read this statement:

Carbon dioxide levels in the atmosphere are rising out of control.

What evidence is there in the graph for and against this statement?

Look at the section of the graph for the last 20 000 years.

What conclusion can be made about the release of carbon dioxide into the atmosphere and also its removal from the atmosphere during the last 20 000 years?

Describe how human activity has contributed to the trends in the graph and suggest how this activity could affect biodiversity.

The information in the box is part of a scientific journal report.

Growing crops with shiny leaves could cause an annual global cooling of over 0.1 °C.

This is almost 20% of the total global temperature increase since the Industrial Revolution.

Most crop plants have non-shiny leaves.

A few varieties of crop plants do have shiny leaves but they do not all produce high yields.

Explain how scientists could use selective breeding to help reduce global temperatures.

The diagram shows a potometer.

Why is structure X needed?

A Maintains temperature of the apparatus

B Provides the plant with mineral ions

C Returns the air bubble to its original position

D Sucks water up from the beaker

Look at the diagram of a potometer.

How can the apparatus be changed to increase the rate of water uptake?

A Add more water to the beaker

B Place an electric fan next to the apparatus and switch the fan on

C Place a plastic bag over the plant

D Remove half of the leaves from the plant