Plant Tissues, Organs & Systems (AQA GCSE Biology: Combined Science)

Exam Questions

2 hours15 questions
1a1 mark

Figure 1 shows a cross section of a leaf.

Figure 1

plant-tissue

Which of the options below correctly describes the organisational structure of a leaf?

  • Cell

  • Tissue

  • Organ

  • Organ system

1b1 mark

Name structure X and Y in Figure 1.

1c2 marks

Describe how structure X (in Figure 1) helps control gas exchange in response to changing environmental conditions.

1d1 mark

Which feature of palisade mesophyll cells makes them adapted for efficient photosynthesis?

  • They are transparent to allow light to pass through.

  • They have a thick waxy coating.

  • Contain lots of mitochondria

  • Contain lots of chloroplasts

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2a1 mark

Figure 2 shows a drawing of the cross-section of a plant root.

The transport tissues are labelled.

Figure 2

xylem

What is the structure labelled X?

2b1 mark

Which substance is transported in the phloem.

  • Water.

  • Dissolved sugars.

  • Mineral ions.

  • Carbon dioxide.

2c1 mark

Which of A to D best represents the direction of movement of substances in the phloem and structure X?

  Structure X Phloem
A Up only Up and down
B Up and down Up and down
C Up and down Up only
D Up only Up only



                                         

    2d1 mark

    What is the name given to the flow of water from the roots to the leaves via the xylem vessel?

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    3a2 marks

    Complete the sentence.

    Choose the answer from the box

    Xylem         Sugars          Phloem          Mineral ions         Translocation         Water         Leaves     Transpiration          Roots         Photosynthesis

    The __________ transports food substances such as dissolved __________ made in the __________ to the rest of the plant, this process is called __________ .

    3b1 mark

    Which of the statements A to D does not refer to the xylem?

    • Tiny pores allow water and mineral ions to enter.

    • Composed of tubes of elongated living cells. 

    • Strengthened by lignin.

    • Dead cells form a hollow tube.

    3c2 marks

    Complete the sentences.

    Choose the answers from the box

    Evaporation         Diffusion          Active transport         

    Osmosis          Translocation           Transpiration          

    Water moves into the cytoplasm of root hair cells by the process of __________ .

    Mineral ions move into the cytoplasm of root hair cells by the process of __________ .

    3d2 marks

    Root hair cells possess long hair-like projections.

    Explain why this is a beneficial adaptation for absorbing water and mineral ions.

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    4a1 mark

    What is the predominant process by which water is lost from the leaf?

    • Diffusion.

    • Evaporation.

    • Translocation.

    • Photosynthesis.

    4b2 marks

    Suggest two reasons why transpiration is beneficial for the plant.

    4c4 marks

    Figure 3 shows the movement of water through a plant. Arrows indicate the direction of movement.

    Figure 3

    plant

    Explain how the transpiration stream happens in plants. Use the information in Figure 3.

    4d1 mark

    What would happen to the transpiration rate of the plant in Figure 3 during the night time?

    • Transpiration increases

    • Transpiration remains constant

    • Transpiration stops

    • Transpiration decreases

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    5a2 marks

    Table 2 below lists some of the factors that affect the rate of transpiration in plants.

    Table 2

    Factor Decreases transpiration rate? Increases transpiration rate?
    Increase in light intensity    
    Increase in temperature    
    Increase in air flow    
    Increase in humidity    

    Complete the table by placing a tick (✔) for each factor, in the correct box that corresponds to either a decrease or increase in transpiration rate.

    5b1 mark

    Two students set up the equipment shown in Figure 4 to investigate the effect of air flow on the rate of transpiration of a plant shoot.

    Figure 4

    reservoir

    What is the equipment shown in Figure 4 called?

    5c2 marks

    Using the equipment shown in Figure 4, some students investigated transpiration in a plant.

    The students initially left the equipment for 20 minutes and recorded the distance moved by the bubble.

    They then repeated the experiment but placed a moving electric fan next to the plant. Two different fan speeds were tested (fast and slow).

    The results are shown in Figure 5  

    Figure 5

    bubble-distance

    Explain why the air movement, caused by the fan, affects the rate of uptake of water by the shoot.

    5d2 marks

    Identify two factors that should be kept the same during the experiment...

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    1a1 mark

    Like animals, plants exchange substances with the environment to obtain what they need to survive and to remove waste.

    Substances need to be moved around a plant.

    Name two organs through which substances move in a plant.

    1b4 marks

    The roots of a plant use active transport to absorb mineral ions.

    A mature bean plant is replanted in soil lacking mineral ions, as shown in Figure 1.

    Figure 1

    bean-plant-minerals

    Describe and explain the impact of the soil on the ability of the roots of the bean plant to take up water.

    1c3 marks

    Explain what is meant by the term 'transpiration stream'

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    2a3 marks

    Plant leaves have many adaptations to maximise the rate at which they can photosynthesise.

    A group of students wanted to investigate the behaviour of stomata in different plants.

    Figure 2 is a drawing of the underside of a leaf of one of the plants as visualised under a light microscope.

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    Name cell X in Figure 2 and outline its role in the leaf.

    2b2 marks

    Calculate the number of stomata per mm2 of this leaf surface.

    2c2 marks

    Another plant species has 200 stomata per mm2 of its leaf surface. An increased number of stomata is not always advantageous.

    Explain why.

    2d3 marks

    The students then measured the mean widths of the stomata from three different species of plant which had been growing under different light conditions.

    Table 1 shows their results.

    Table 1

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    Species A is unlikely to be found growing in a hot, dry desert.

    Explain why, using data from Table 1.

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    3a1 mark

    Figure 3 shows a drawing of the cross-section of a plant root.

    The transport tissues are labelled.

    Figure 3

    U9SJ5iIW_3

    What tissue is labelled X?

    3b1 mark

    Name two substances transported by the xylem.

    3c3 marks

    Compare the structure of the xylem with that of tissue X.

    3d3 marks

    A process called translocation occurs in tissue X.

    What is translocation and why is it important for plants?

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    4a3 marks

    Figure 4 shows two guard cells surrounding an open stoma and two guard cells surrounding a closed stoma.

    Figure 4

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    When light intensity is low, the stoma closes.

    Describe how the stoma close.

    4b1 mark

    Guard cells have cell walls with unevenly distributed cellulose.

    Suggest why this is important.

    4c1 mark

    A student investigated the effect of varying concentrations of salt solution on the opening of stomata on the lower epidermis of a leaf.

    Her results are shown in Table 2.

    Table 2

    Concentration of salt solution in mol /dm3 Number of stomata in field of view Number of open stomata in field of view Percentage (%) of open stomata in field of view
    0.0 15 15 100
    0.2 18 18 100
    0.4 13 11 85
    0.6 16 10 65
    0.8 15 6 40
    1.0 18 4 22

    The student calculated one of the percentages for open stomata in the field of view incorrectly.

    Identify for which solution the result was incorrect and give the correct value.

    4d1 mark

    Write a conclusion for the results of the experiment as shown in Table 2.

    4e3 marks

    The student measured the real diameter for the field of view to be 0.475 mm.

    Calculate the total number of stomata per mm2 of the leaf epidermis placed in 0.8 mol / dm3 salt solution if the value of π (pi) is 3.14.

    Show your working.

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    5a1 mark

    A potometer can be used to measure the uptake of water by a leafy shoot.

    Figure 5 shows a potometer.

    Figure 5

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    A group of students measured the uptake of water by the shoot under normal conditions.

    As water was taken up by the shoot, the level of water in the capillary tube decreased.

    Explain why.

    5b3 marks

    The water level of the shoot was recorded at 2 minute intervals over a 12 minute period.

    The results are shown in Table 3.

    Table 3

    Time in minutes 0 2 4 6 8 10 12
    Level of water in capillary tube (cm3) 2.8 3.7 4.8 5.6 6.7 7.7 8.8

    The area of the cross section of the capillary tube was 0.6 mm2.

    Calculate the volume of water taken up by the shoot in mm3 per minute.

    Show your working.

    5c2 marks

    The students decided to repeat the investigation but this time placed a humidifier in the room next to the potometer.

    A humidifier adds water vapour to the air.

    Suggest and explain how the results would be different to those obtained in Table 3.

    5d3 marks

    The students considered repeating the investigation again by measuring the uptake of water at different temperatures.

    They were conscious of not leaving the leaves for too long at temperatures above 30 °C.

    Explain why.

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    1a3 marks

    Explain how palisade cells are adapted to their function.

    1b4 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.

    1c4 marks

    Explain how the leaf is adapted for gas exchange.

    1d6 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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    2a1 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 environment.

    • The rate of transport fluctuates between different plant species.

    2b3 marks

    Figure 1 shows an aphid feeding on a plant stem.

    Figure 1

    aphid

    Explain why they target structure X.

    2c4 marks

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

    2d6 marks

    Compare the transport systems in plants and animals.

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    3a1 mark

    Figure 2 shows a cross section of a leaf.

    Figure 2

    plant-tisse

    Describe what is unusual about the underside of the leaf.

    3b4 marks

    Explain which kind of environment the leaf shown in Figure 2 is adapted for.

    3c3 marks

    Many plants that grow in hot arid environments like the desert, take in CO2 during the night and store it.

    Explain how this is advantageous to the plant.

    3d4 marks

    During an exam a student wrote the following statement:

    "Transpiration and photosynthesis in plants is a compromise".

    Suggest what evidence they could use to support this statement.

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    4a3 marks

    The development of root hair cells is complicated and under the control of many genes.

    Scientists have created mutants where particular genes are deleted ('knocked out'), these result in different phenotypes (observable characteristics). Table 1 shows the effect of knocking out various genes on the growth of root hair cells.

    Table 1

    Gene Effect of deleting the gene Phenotype
    WEREWOLF (WER1) Root hairs cells form on every cell Hairy root
    AGP14 Increased length of root hair cells Extra Hairy root
    CPC Reduced number of root hair cells Bald root
    DER6 Shortened length of root hair cells Spiky root

    Suggest why it is important for a plant to have such developmental control over the growth of root hair cells.

    4b5 marks

    Explain why a tree loses more water during the day compared to night time.

    4c4 marks

    Xerophytes are plants that are specially adapted to live in the desert.

    Explain why Xerophytes need to be adapted to their environment.

    4d3 marks

    Describe the special features that allow guard cells to open and close stomata.

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    5a4 marks

    Explain how a potometer can be used to estimate transpiration rates. 

    5b3 marks

    A student set up a potometer and stated that:

    "the potometer can tell me exactly how much water has been lost through transpiration".

    Suggest what is inaccurate about the student's statement.

    5c6 marks

    A student investigated the effect of light intensity on transpiration in a plant using a mass potometer as shown in Figure 3.

    Figure 3

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    Six plants were used, three in each of two different conditions: in a room or in the same room next to a bright lamp. Table 2 shows the results.

    Table 2

    Plant In a room (% loss in mass) Next to a light (% loss in mass)
    1 4 12
    2 3 10
    3 4 11
    Mean 3.6 11

    The student then set up an investigation to study the effect of increasing humidity levels on transpiration.

    Explain why the results of the two investigations may differ.

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