Transpiration

Figure 9 shows a stoma on the lower epidermis of a leaf as seen using a

Draw the stoma and two cells around it in the box.

Give the name of the two cells around the stoma.

A student observed that a plant in a room had grown towards the light.

Name the plant hormone that causes the plant to grow towards the light.

Name the type of tropism that causes the plant to grow towards the light.

Figure 10 compares the root hair cells of two plants.

Plant A is adapted to growing in wet soil.

Plant B is adapted to growing in dry soil.

Compare the root hair cells of Plant A with the root hair cells of plant B.

Figure 11 shows sections of a leaf from plant A and a leaf from plant B.

plant A (wet soil)
plant B (dry soil)

Figure 11

State two differences in the leaf structure shown in Figure 11 that help plant B to survive in a dry environment.

Figure 12 shows the lower epidermis of a leaf, with a stoma labelled.

(Source: © Quagga Media/Alamy Stock Photo)

Figure 12

State the number of guard cells shown in Figure 12.

State one gas that leaves the stomata and one gas that enters the stomata during daylight.

gas leaving stomata

gas entering stomata

State why the stomata close.

A student wanted to view the cross-section of a leaf on a prepared slide.

Describe how a light microscope would be used to observe this slide.

Sugars are transported from the leaves to the rest of the plant.

Explain how sugars are moved through the plant.

Figure 7 shows the structure of a leaf.

Which layer has the highest number of chloroplasts per cell?

When iodine solution was put onto these cells, small parts of the cells became blue‑black.

Name the substance stored in the parts of the cells that turned blue‑black.

State how the guard cells control the amount of gas exchange that occurs through the stomata.

A scientist measured the thickness of the cuticle from the leaves of plants growing in soil that had a different percentage of water content.

The scientist measured six plants at each percentage of water content.

Figure 8 shows the results.

Calculate the mean thickness of cuticle for the plants growing in soil containing 15% water.

Give your answer to one decimal place.

Explain why the thickness of the cuticle is different when a plant is grown in soil with a higher water content.

State one other way that the leaves of plants are adapted to help plants grow in soil with low water content.

Figure 13 shows a root hair cell from a plant.

Name the part labelled X.

State one way that the structure of the root hair cell increases the volume of substances it absorbs.

Explain why root hair cells do not contain chloroplasts.

*(c) The arrows in Figure 15 show the direction of water movement through a tree.

Explain how water is moved from the soil, through the plant and into the air.

7 A farmer wants to make sunflower seeds germinate faster.

(a) Which is the best hormone for the farmer to use?

(b) The sunflower plants grew and flowered. The farmer noticed that the flowers faced a different direction at different times of the day. Figure 8 shows a sunflower at different times of the day. This movement is an example of phototropism.

(Source: © yevgeniy11/Shutterstock)

Figure 8

(i) This movement of the flower was in response to the light. Explain how the sunflower changed direction throughout the day.

(ii) Explain how water moves through the stem of the sunflower plant to the leaves.

(iii) Sunflower leaves are large. Explain why large leaves are an advantage to the plant.

8 (a) Figure 14 shows a diagram of a plant root hair cell.

Figure 14

(i) Name the part labelled R.

(ii) Explain one adaptation of a root hair cell that increases the absorption of water and mineral ions.

(b) Figure 15 shows xylem and phloem from the stem of a plant.

Figure 15

(i) Living cells in phloem use energy to transport sucrose. Which organelles release energy in living cells?

(ii) Describe two features of the structure of xylem vessels that can be seen in Figure 15.

(c) A scientist investigated how the flow of air affected the rate of transpiration in a plant. A fan was used to change the flow of air. The volume of water taken up by the plant was measured. Figure 16 shows the results of this investigation. fan switched on

time in minutes

Figure 16

(i) Explain why switching on the fan caused a change in the volume of water taken up by the plant.

(ii) Give one reason why the volume of water taken up by the plant was also measured when the fan was not switched on.

(iii) Calculate the rate of water uptake from 8 minutes to 10 minutes when the fan was switched on. Use the equation

_{..............................................................}mm³ per minute

2 (a) Figure 2 shows xylem and phloem from the stem of a plant.

(i) Living cells in phloem use energy to transport sucrose. Which organelles release energy in living cells?

(ii) Describe two features of the structure of xylem vessels that can be seen in Figure 2.

(b) A scientist investigated how the flow of air affected the rate of transpiration in a plant. A fan was used to change the flow of air. The volume of water taken up by the plant was measured. Figure 3 shows the results of this investigation. fan switched on

time in minutes

Figure 3

(i) Explain why switching on the fan caused a change in the volume of water taken up by the plant.

(ii) Give one reason why the volume of water taken up by the plant was also measured when the fan was not switched on.

(iii) Calculate the rate of water uptake from 8 minutes to 10 minutes when the fan was switched on. Use the equation

_{..............................................................}mm³ per minute

Figure 12 shows how the leaves are arranged on a plant.

Which reason explains why the leaves are arranged in this way?

Figure 13 shows guard cells and stomata on the lower surface of a leaf.

(Source: © Rattiya Thongdumhyu/Shutterstock)

Figure 13

Measure the length of the line on the labelled guard cell in mm.

The actual length of the labelled guard cell is 0.05 mm.

Calculate the magnification of this image.

Figure 14 shows the number of stomata per mm² on the lower surface of leaves from plants growing in soils with different water content.

Explain the difference in the number of stomata per mm² on the leaves of the plants grown in dry and wet soils.

*(d) Figure 15a shows a plant that has been placed on its side.

Figure 15b shows the same plant after 5 days.

Explain why the growth of the plant has changed.

Figure 2 shows an area of woodland with some small plants growing in the ground between the trees.

(Source: © Maksym Holovinov/Shutterstock)

Figure 2

Name a group of organisms that break down the dead leaves and release mineral ions into the soil.

The mineral ions are absorbed from the soil into the roots of plants.

Describe how these mineral ions are transported from the roots to the leaves of the plants.

A scientist recorded the mean light intensity and the mean number of small plants per m² for six 25 m² areas of the woodland.

Figure 3 shows the results.

Explain the effect of light intensity on the number of small plants per m².

State one variable the scientist should have controlled to make sure the light intensity measurements could be compared.

The scientist selects an area near the edge of the woodland where many stinging nettles are growing.

This area is partly shaded by the trees.

Describe how the scientist should use a belt transect to investigate how light intensity affects the growth of stinging nettles.

Figure 18 shows the leaves and flowers of water lily plants (Nymphaea odorata) on a lake.

Water lilies have stomata on the upper surface of the leaves.

Explain why water lilies have no stomata on the lower surface of the leaves.

The white petals of the water lily flowers cannot photosynthesise.

Which structure in leaf cells is the site of photosynthesis?

Glucose is made by photosynthesis.

Glucose is converted to another sugar to be transported in the plant.

What is the name of this sugar?

Describe how this sugar is transported from the leaves to the flowers of the water lily.

Figure 19 shows water lilies growing in a lake in Europe.

One water lily plant was brought from America 10 years ago and planted in the lake shown in Figure 19.

Explain why this non‑indigenous plant now covers the whole surface of the lake.

Explain how the water lilies will affect the biodiversity of this lake.

Figure 2 shows the leaves and flowers of water lily plants (Nymphaea odorata) on a lake.

Water lilies have stomata on the upper surface of the leaves.

Explain why water lilies have no stomata on the lower surface of the leaves.

The white petals of the water lily flowers cannot photosynthesise.

Which structure in leaf cells is the site of photosynthesis?

Glucose is made by photosynthesis.

Glucose is converted to another sugar to be transported in the plant.

What is the name of this sugar?

Describe how this sugar is transported from the leaves to the flowers of the water lily.

Figure 3 shows water lilies growing in a lake in Europe.

One water lily plant was brought from America 10 years ago and planted in the lake shown in Figure 3.

Explain why this non‑indigenous plant now covers the whole surface of the lake.

(a) Photosynthesis occurs in leaves.

Which substance is needed for photosynthesis?

A leaf cell is 0.08 mm long.

Calculate the length of the image of this cell after it has been magnified 50 times using a microscope.

Pine trees can live in dry soil.

Use words from the box to complete the sentences.

The pine leaf has stomata in pits to reduce the loss of_........ .

The pine leaf is needle-shaped to reduce the surface_........ .

Figure 5 shows young tomato plants growing in a glasshouse.

The young tomato plants are growing towards the light.

Explain how a plant hormone causes these shoots to grow towards the light.

(a) Figure 1 shows a cross section of a leaf.

What is the name of layer A?

Explain the function of the spaces between the cells in layer B.

Explain the function of part C in Figure 1.

Xerophytes are plants adapted to live in very dry conditions.

State two differences between the leaf structure of a xerophyte and the leaf structure shown in Figure 1.

(a) (i) Water enters a plant through root hair cells.

Root hair cells have

Explain how water in the root is transported to the leaves of the plant.

How is sucrose transported from the leaves to other parts of the plant?

Figure 7 shows the average size of stomata in a leaf during one day.

Name the cells that change the size of stomata.

Describe the trend shown in Figure 7.

The temperature increased from 8 am to 1 pm.

Explain why this affected the size of the stomata.

State why a coverslip is placed on top of the leaf peel.

Explain why the leaf peel rather than the whole leaf was viewed with a microscope.

The student drew a biological diagram of the leaf peel taken from the underside of the leaf.

Figure 23 shows this diagram.

State the number of stomata visible on Figure 23.

The student observed that the stomata were open.

Describe how stomata open.

*(c) Figure 24 shows xylem and phloem. Xylem and phloem are involved in the transport of substances through a plant.

Use Figure 24 to help you describe how water and sucrose move through a plant.

A student compared the number of stomata on the upper and lower surfaces of a leaf.

She completed a leaf peel as shown in Figure 5.

leaf coated with clear layer of nail varnish layer of nail varnish placed nail varnish
removed on a microscope slide

Figure 5

The layer of nail varnish shows an impression of the cells on the surface of the leaf.

State why a coverslip is placed on top of the leaf peel.

Explain why the leaf peel rather than the whole leaf was viewed with a microscope.

The student drew a biological diagram of the leaf peel taken from the underside of the leaf.

Figure 6 shows this diagram.

State the number of stomata visible on Figure 6.

The student observed that the stomata were open.

Describe how stomata open.

The leaf peel from the upper surface of this leaf showed no stomata.

Explain why it is an advantage to the plant to have this distribution of stomata in the upper and lower surfaces of the leaf.

(a) Figure 16 shows the effect of light intensity and temperature on the rate of photosynthesis.

Describe the effect of light intensity on the rate of photosynthesis.

Explain the effect of temperature on the rate of photosynthesis.

A student measured the rate of photosynthesis using algal balls in a laboratory. The tube of algal balls was kept at a temperature of 25 °C and was moved to different distances from a light source.

The results of this investigation showed that the rate of photosynthesis is

*(c) Explain how substances are moved through a plant by transpiration and translocation.

(a) Figure 18 shows an investigation into the growth of plant shoots.

Experiment 1:

The tip of a shoot was removed from the plant.

There was no growth in the shoot after 3 days.

Experiment 2:

The tip of a shoot was cut off and then placed back onto the shoot.

The shoot had grown 6 mm after 3 days.

Give one variable that must have been controlled for the plant shoot to grow vertically, as shown in experiment 2.

State one conclusion that could be made based on these two experiments.

Which plant hormone causes growth in the plant shoot?

Explain one way that this investigation could be improved.

*(b) Marram grass is a plant that grows on exposed areas of sand dunes.

Figure 19 shows marram grass growing and a cross section through a leaf of marram grass.

Explain how marram grass is adapted to survive in the hot, windy and dry conditions of a sand dune.