Plant Structure (Edexcel GCSE Biology)

Exam Questions

2 hours14 questions
1a
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5 marks

Figure 1 shows a cross-section of a leaf.fig-1-1bio-2h-june19-qp-gcse-bio

Figure 1

(i)
What is the name of layer A?

(1)

  A spongy mesophyll
  B palisade mesophyll
  C upper epidermis
  D waxy cuticle

(ii)

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

(2)

(iii)
Explain the function of part C in Figure 1.

(2)

1b
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2 marks

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.

1...............................................

2................................................

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2a
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3 marks

Photosynthesis occurs in leaves.


(i)

Which substance is needed for photosynthesis?

(1)

  A carbon dioxide
  B glucose 
  C oxygen
  D nitrogen

(ii)

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.

(2)

.................................... mm

2b
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2 marks

Pine trees can live in dry soil.

Use words from the box to complete the sentences.

thickness water light
area chlorophyll volume


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

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

2c
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2 marks

Figure 1 shows young tomato plants growing in a glasshouse.fig-5-1bio-2f-june19-qp-gcse-bio

Figure 1

The young tomato plants are growing towards the light.

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

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3a
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4 marks

Separate: Biology Only

A plant leaf contains various structures that makes it adapted for the process of photosynthesis.

Complete the following by drawing lines to connect each listed structure with the correct adaptation.

Structure   Adaptation
     
Waxy cuticle   Allows gas exchange to occur
     

Stomata

  Tightly packed with chloroplasts for maximum absorption of light
     
Palisade mesophyll   Protect the leaf from water loss
     

Spongy mesophyll

  Increases the surface area to volume ratio for the diffusion of gases

3b
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4 marks

Separate: Biology Only

Figure 1 shows the cross section of a leaf.

figFigure 1

Structure Y represents a vascular bundle.

(i)

Identify two types of tissue found in structure Y.

(2)

(ii)

Describe the function of each type of tissue identified at part (i).

(2)

3c
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3 marks

Separate: Biology Only

Layers X and Z in Figure 1 form the outer boundaries of the leaf.

(i)

State one visible difference between layers X and Z.

(1)

(ii)

The cells in layer X are transparent.

Explain the importance of this to the plant.

(2)

3d
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3 marks

Separate: Biology Only

Carbon dioxide must enter the chloroplasts within plant cells for photosynthesis to occur.

Describe the movement of carbon dioxide from the atmosphere into the chloroplasts.

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4a
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2 marks

State the role of lignin in xylem cells.

4b
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2 marks
(i)
Describe a root hair cell.

(1)

(ii)
What characteristic of the root hair cell's cytoplasm contributes to its low water potential?

(1)

4c
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1 mark

Select the primary substance transported in phloem cells.

  A Water
  B Sucrose
  C Minerals
  D Amino acids
4d
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2 marks

Separate: Biology Only

Match each adaptation to its function for the xylem or the phloem in Table 1 below.

Table 1

Adaptation Function
  Strengthening tubes in xylem for water transport
Few subcellular structures  

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5a
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3 marks

Separate: Biology Only

Despite having modified leaves that function as spines, cacti are highly successful in arid  environments. 

Describe the physiological and structural adaptations in cacti that contribute to their ability to thrive in dry, hot conditions.

5b
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2 marks

Separate: Biology Only

State two functions of the upper epidermis in plant leaves.

5c
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1 mark

Separate: Biology Only

Which of the following options describes the primary role of the deep grooves in Marram grass leaves?

  A Enhance photosynthesis
  B Facilitate water uptake
  C Protect stomata from direct exposure
  D Increase leaf flexibility
5d
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4 marks

Complete Table 1 below by comparing the characteristics of xylem and phloem cells.

Table 1

Characteristic Xylem cells Phloem cells
Type of cells    
Main function    

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1a
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4 marks

Figure 1 shows part of a root as seen using a light microscope.

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Figure 1

Figure 2 shows information about the two types of cells labelled in Figure 1.

type of cell surface area in µm2 volume in µm3 surface area to volume ratio
root surface cell 4 000 220 000 1:55
root hair cell 37 000 259 000  

Figure 2

(i)
Calculate the surface area to volume ratio of the root hair cell. 

(2)

(ii)
Explain how root hair cells are adapted for their function in the plant. 

(2)

1b
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2 marks

Root hair cells can be viewed using an electron microscope. 

Describe and explain how the image in Figure 1 would appear different if taken using an electron microscope.

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2a
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2 marks

Figure 1 shows the mass of glucose produced in each layer of the leaf per hour.  

q2a_plant-structures_eexcel_gcse_biology_sqFigure 1

Describe the difference in the mass of glucose produced per hour in the palisade mesophyll and the mass of glucose in the spongy mesophyll shown in Figure 1. 

2b
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4 marks

Using your understanding of the structure of the leaf, explain the data in Figure 2.

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3a
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2 marks

A student wanted to view the stomata on the underside of a leaf.

She completed a leaf peel as shown in Figure 1. 

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Figure 1

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

Explain the function of the stomata in the leaf.

3b
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1 mark

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

Figure 2 shows this diagram.

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Figure 2

State the number of stomata visible in Figure 2. 

3c
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5 marks

On the underside of the leaf, the student found that they could see 30 stomata. 25 of these were open. 

(i)
Describe how stomata open.

(3)

(ii)
Calculate the percentage of stomata that were open. 

(2)

3d
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2 marks

The student completed another leaf peel but of the upper surface of the leaf instead. 

They found that there were no stomata on the upper surface of the leaf.

Explain why it is an advantage to the plant to have this distribution of stomata on the upper surface of the leaf. 

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4a
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4 marks

Xylem and phloem are both types of vessels that transport substances through plants. 

During periods of drought, xylem and phloem can experience shrinkage. This can be observed by measuring the circumference of the trunks of trees. 

Figure 1 shows the difference in circumference of three trees before and after a seven day period of drought.

species name trunk circumference before drought (mm) trunk circumference after drought (mm)
Cedrela montana 315 313
Handroanthus chrysanthus 358 355
Podocarpus oleifolius 276 275

Figure 1

(i)

Calculate the percentage decrease in the trunk circumference of Handroanthus chrysanthus before and after the period of drought. 

(2)

(ii)
Handroanthus chrysanthus had a larger leaf surface area than Podocarpus oleifolius. 

Suggest why this might have led to a greater decrease in trunk circumference in the Handroanthus chrysanthus.

(2)

4b
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4 marks

Figure 2 shows the structure of a xylem and a phloem vessel. 

7

Figure 2

(i)
Name two substances that are transported in xylem vessels. 

(2)

(ii)
Describe the features of a xylem vessel that make it adapted for its function in the plant. 

(2)

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5a
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2 marks

Figure 1 shows a cactus plant.

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Figure 1

Describe two features that allow this plant to grow in hot, dry conditions. 

5b
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5 marks

Another plant that is adapted for hot, dry conditions is marram grass (Ammophila arenaria). This species grows mostly in sand dunes where there is very little fresh water. 

Some of its adaptations are as follows:

  • Leaves can roll up to reduce the surface area exposed to the wind
  • Stomata are found in grooves within the protected inner part of the leaf
  • Humid air is trapped within the protected inner part of the leaf, aided by small hairs
(i)
Explain why it is beneficial for the plant to have these adaptations.

(2)

(ii)
Suggest how this species could have evolved these adaptations. 

(3)

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66 marks

Marram grass is a plant that grows on exposed areas of sand dunes.

Figure 1 shows marram grass growing and a cross section through a leaf of marram grass.

fig-19-1bio-2h-june18-qp-gcse-bio

Figure 1

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

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1a
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1 mark

Figure 1 shows how the leaves are arranged on a plant.

fig-12-1bio-2f-nov2021-qp-gcse-bio

Figure 1

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

  A the upper leaves allow more light to reach the lower leaves
  B the leaves do not need stomata 
  C the phloem in the leaves will absorb more water
  D more insects will be attracted to the plant to eat the leaves
1b
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3 marks

Figure 2 shows guard cells and stomata on the lower surface of a leaf.

A ruler has been overlayed on the image for scale purposes.

edexcel-gcse---6-2-plant-structure8b

Figure 2

Use the ruler overlay to 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.

1c
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2 marks

Figure 3 shows the number of stomata per mm2 on the lower surface of leaves from plants growing in soils with different water content.

fig-14-1bio-2f-nov2021-qp-gcse-bio

Figure 3

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

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2a3 marks

Explain how palisade cells are adapted to their function.

2b4 marks

A scientist saw the following query on a question and answer website:

"If plant leaf epidermis cells are the outermost cells in a leaf and closer to the sun, why do they not contribute much to photosynthesis?"

Suggest a suitable response to the query.

2c4 marks

Explain how the leaf is adapted for gas exchange.

2d6 marks

Sketch an annotated diagram of the cross-section of a leaf. You do not need to include the structures responsible for transport of food and water.

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3a1 mark

Which statement from A to D would indicate that transport of materials in the phloem involves metabolic processes rather than just a physical process?.

  • Material can be transported in both directions within the phloem.

  • Removing the leaves results in a decrease in rate of transport.

  • No transport is observed if the plants are grown in an anoxic (no oxygen) environment.

  • The rate of transport fluctuates between different plant species.

3b3 marks

Figure 1 shows an aphid feeding on a plant stem.

aphid

Figure 1

Explain why they target structure X.

3c4 marks

Describe how the xylem is adapted for the transport of water.

3d6 marks

Compare the transport systems in plants and animals.

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