Transport in Plants (Edexcel GCSE Biology: Combined Science)

The graph shows the changes in stomatal size over a 12 hour period throughout the day.

Describe the changes in stomatal size over the 12 hour period.

The temperature increased from 8 am to 1 pm. 

Explain why this affected the size of the stomata.

Figure 1 shows a stoma before and after opening. 

Figure 1

Name the cells shown in this image and describe the changes that occur in these cells that cause the stoma to open.

A pair of students wanted to investigate how water moves through a plant.

They placed a plant with exposed roots into a conical flask containing water. They then placed a mass balance below to measure how the mass of water changed during the experiment.

They set up their equipment as shown in Figure 1. 

Figure 1

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(2)

Explain how water is moved through a plant from the roots to the surrounding air.

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(2)

Glucose is produced in the leaves of a plant through the process of photosynthesis. 

It can then be transported to other areas around the plant in order to be used. 

Explain how glucose is transported through a plant.

When the sugars travel through the plant they are transported to the place where they are required, known as a sink. 

(1)

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The process of transporting sugars through the plant is aided by active transport.

Describe how active transport can be used to transport sugars in a plant. 

A student set up a potometer to investigate the effect of temperature on the rate of transpiration. 

Figure 1 shows the equipment they used. 

Figure 1

Explain the function of the reservoir in this equipment. 

The student placed the equipment in areas with different air temperatures. They left the equipment for 45 minutes and recorded the rate of transpiration during that time. 

Their results are shown in Figure 2. 

Figure 2

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(2)

Explain how glucose production could be affected if this plant lost a lot of water. 

An investigation was carried out over a 12-hour period to compare transpiration in two species of plant, Coleus and Begonia. 

The mass of each plant was recorded before and after the 12-hour period to find out the effect of transpiration.

The investigation was repeated five times with the same plants.

Figure 1 shows the change in mass of each plant over each 12-hour period.

Figure 1

(2)

The wilted Coleus plant was observed to recover more quickly than the wilted Begonia plant after they were both watered.

Explain this observation.

Figure 3 shows xylem and phloem.

Xylem and phloem are involved in the transport of substances through a plant.

Figure 3

Use Figure 3 to help you describe how water and sucrose move through a plant.