Plant stems, fibres and mineral ions: Edexcel International A Level Biology questions

Every Edexcel International A Level Biology exam question on Plant stems, fibres and mineral ions (specification points 4.5–4.9), 2019–2025, with its mark scheme and examiner’s report.

All 116 questions on Plant stems, fibres and mineral ions, as a list

June 2025, AS Unit 2, Q4(a)(ii) (1 mark): Give one conclusion that can be made about the effect of age on the mean percentage of both cellulose and lignin content of bamboo plants. (1)
June 2025, AS Unit 2, Q4(c)(i) (1 mark): Which of the following are functions of xylem vessels? 1. give support to the plant 2. translocation of organic solutes to the leaves 3. transport of inorganic
June 2025, AS Unit 2, Q4(c)(ii) (1 mark): Give one difference between the distribution of phloem and xylem in the leaf compared with their distribution in a transverse section of a stem. (1)
June 2025, AS Unit 2, Q5(a) (2 marks): The photograph shows a drinking cup. (Source: © Alex Hinds / Alamy Stock Photo) This cup is made from parts of a sugarcane plant that are left over from commerc
June 2025, AS Unit 2, Q7(a)(i) (2 marks): Give two reasons why water is important to the strawberry plants. (2) 1 2
June 2025, AS Unit 2, Q7(a)(ii) (3 marks): The nutrient solution contains nitrate ions and calcium ions. Explain the importance of these ions to the strawberry plants. (3)
June 2025, AS Unit 2, Q7(b) (1 mark): The diagram shows the strawberry production in five continents, P, Q, R, S and T, in 2021. P 2.4 Q 24.9 T R 177.9 69.1 S 85.7 Continent Q produced 634 288 000 k
June 2025, AS Unit 2, Q7(c)(i) (2 marks): In plants, magnesium ions are needed to activate enzymes required for: • inorganic ion uptake • protein synthesis • photosynthesis. The diagram shows how the at
June 2025, AS Unit 2, Q7(c)(ii) (6 marks): Farmers concluded that they would make more money if magnesium ions were added to growing wheat plants. Discuss this conclusion. Use all the information in part
January 2025, AS Unit 2, Q3(b)(i) (2 marks): Give two conclusions for the effect of these treatments on the calcium ion content in the roots of these two types of maize. (2) 1 2
January 2025, AS Unit 2, Q6(a)(i) (1 mark): Which of the labelled structures is a xylem vessel? (1) A W B X C Y D Z
January 2025, AS Unit 2, Q6(a)(ii) (1 mark): Which of the labelled structures contains sieve plates? (1) A V B W C X D Y
January 2025, AS Unit 2, Q6(a)(iii) (3 marks): Explain the advantages for this millipede of being able to make holes in xylem and phloem. (3)
January 2025, AS Unit 3, Q1(a) (2 marks): Name two types of fibre cells found in a plant. (2) 1 2
January 2025, AS Unit 3, Q1(b)(i) (1 mark): State what is meant by the term tensile strength. (1)
January 2025, AS Unit 3, Q1(b)(ii) (4 marks): Describe how to investigate the relationship between the length of these fibres and their tensile strength. (4)
January 2025, AS Unit 3, Q1(d)(i) (1 mark): State the relationship represented by the gradient. (1)
January 2025, AS Unit 3, Q1(d)(ii) (3 marks): Suggest how differences in the structure of these three fibres could affect their tensile strength. Use the information in the graph, the drawing and the table
October 2024, AS Unit 2, Q5(b)(i) (2 marks): Explain the role of one named molecule that uses calcium ions. (2) Name of molecule Role of molecule
October 2024, AS Unit 2, Q5(b)(ii) (1 mark): Water is also important to plants. Which of the following would transport water down the stem of a plant? (1) A phloem B sclerenchyma C vacuole D xylem
October 2024, AS Unit 2, Q5(c) (2 marks): The photograph shows pods on a soybean plant. pod (Source: © B Christopher / Alamy Stock Photo) The effect of magnesium ions on the number of pods per soybean p
October 2024, AS Unit 2, Q5(d) (4 marks): In another investigation, the effect of magnesium ions on the mass of soybeans and maize grains was studied. The graph shows the results of this investigation.
October 2024, AS Unit 3, Q2(a)(i) (4 marks): Describe a method that could be used to obtain the results for the complete Hoagland treatment, so that it can be compared with the other treatments. (4)
October 2024, AS Unit 3, Q2(a)(ii) (2 marks): Calculate the percentage increase in shoot dry mass when VCL is added to Hoagland’s solution. (2) Answer %
October 2024, AS Unit 3, Q2(b)(ii) (2 marks): The photographs show the appearance of plants following each treatment. The photograph for each pair of plants has its own scale bar. X Y 30 mm 10 mm 30 mm 50 m
October 2024, AS Unit 3, Q2(b)(iii) (5 marks): Discuss the use of VCL as a fertiliser. Use all the information from this investigation. (5)
October 2024, Unit 6, Q2(d) (2 marks): Sclerenchyma fibres strengthen plant stems. Describe the structure of a sclerenchyma fibre. (2)
June 2024, AS Unit 2, Q6(a)(ii) (1 mark): Suggest why the closing of the pores reduces water stress in the plant. (1)
June 2024, AS Unit 2, Q6(b) (1 mark): Another effect is the reduction in the absorption of mineral ions, for example magnesium ions. Magnesium ions are needed in the formation of chlorophyll. The ef
June 2024, AS Unit 2, Q6(c) (6 marks): The graphs show three more effects of water stress on wheat plants. Graph A shows the effect of water stress on percentage survival rate. 100 80 Mean percentage
January 2024, AS Unit 2, Q1(a) (1 mark): Estimate the height of the sunflower, using the information in the diagram. Give your answer with appropriate units. (1) Answer
January 2024, AS Unit 2, Q1(b)(i) (1 mark): Name the tissue that would contain structure X. (1)
January 2024, AS Unit 2, Q1(b)(ii) (2 marks): Describe how two structures in this tissue enable it to carry out its function. (2) Structure 1 Structure 2
January 2024, AS Unit 2, Q1(c)(i) (1 mark): Which of the following tissues contain lignin? 1. phloem 2. sclerenchyma 3. xylem (1) A 1 only B 1 and 3 only C 2 and 3 only D 3 only
January 2024, AS Unit 2, Q1(c)(ii) (2 marks): The diagram shows a climbing plant that is growing up a bamboo pole. Suggest two reasons why a climbing plant may have a lower lignin content than a sunflower p
October 2023, AS Unit 2, Q3(a) (3 marks): Some plant cell walls develop secondary thickening. Diagram 1 shows a cell without secondary thickening. Diagram 2 shows part of the cell walls of two adjacent
October 2023, AS Unit 2, Q3(b)(ii) (2 marks): Secondary thickening occurs in sclerenchyma fibres. Explain how secondary thickening contributes to the physical properties of sclerenchyma fibres. (2)
October 2023, AS Unit 2, Q3(c) (2 marks): Some cells in xylem vessels have secondary thickening. The photograph shows pits in the wall of part of a xylem vessel, as seen using an electron microscope. ce
October 2023, AS Unit 2, Q5(a)(i) (1 mark): Which tissue is involved in the transport of magnesium ions in a plant? (1) A amyloplast B plasmodesmata C sclerenchyma D xylem
October 2023, AS Unit 2, Q5(a)(ii) (3 marks): Explain how a lack of magnesium ions could result in yellow leaves and reduced growth. (3)
October 2023, AS Unit 2, Q5(b) (6 marks): Calcium ions are also needed for the growth of vine plants and fruit production. Chicken eggshells contain calcium ions. Some farmers add crushed eggshells to t
October 2023, AS Unit 3, Q1(b)(i) (2 marks): Identify the cell types labelled X, Y and Z. (2) X . Y Z
October 2023, AS Unit 3, Q1(b)(ii) (1 mark): The photograph shows a longitudinal section of where two plant cells meet. (Source: DR KEITH WHEELER / SCIENCE PHOTO LIBRARY) State which of the cells labelled
June 2023, AS Unit 2, Q1(a)(i) (1 mark): Which of the following would be a different colour due to the presence of the stain? (1) A W B X C Y D Z
June 2023, AS Unit 2, Q1(a)(ii) (2 marks): Explain why, after one hour, this part of the stem would be a different colour. (2)
June 2023, AS Unit 2, Q3(b) (2 marks): The digested insects are a source of nitrogen for the pitcher plant. Give two ways in which this source of nitrogen is used by the pitcher plants. (2) 1 2
June 2023, AS Unit 2, Q7(a) (1 mark): The smallest flower on Earth is produced by Wolffia globosa. The flower of W. globosa measures 50 μm in diameter. Which is the ratio for the diameters of the fl
June 2023, AS Unit 2, Q7(b)(ii) (3 marks): Suggest how the corpse lily plant obtains organic solutes, such as sucrose, from one of the tissues in the vine plant. (3)
June 2023, AS Unit 3, Q1(a)(i) (2 marks): Name two types of cell found in plant fibres. (2) 1 2
June 2023, AS Unit 3, Q1(a)(ii) (2 marks): Fibres have cell walls with secondary thickening of lignin. Describe two ways in which secondary thickening affects the properties of the cell. (2) 1 2
June 2023, AS Unit 3, Q1(b)(ii) (3 marks): After soaking, the diameter of each fibre was measured. Describe how fibre diameter could be measured accurately using a microscope. (3)
June 2023, AS Unit 3, Q1(c)(ii) (3 marks): Describe the results of this investigation. (3)
January 2023, AS Unit 2, Q1(a)(i) (3 marks): Label the photograph to show the position of the phloem, sclerenchyma fibres and xylem vessels. (3)
January 2023, AS Unit 2, Q1(a)(ii) (1 mark): How many of the following statements about phloem are correct? • connected to other cells by plasmodesmata • transports water and organic solutes • translocatio
January 2023, AS Unit 3, Q1(a)(i) (2 marks): Describe how you would use the information in the photograph to identify structures A and C. (2)
January 2023, AS Unit 3, Q1(a)(ii) (3 marks): A longitudinal section was taken through one of the labelled tissues A, B or C. The photograph shows a view of some of the cells in this tissue, as seen using a
January 2023, AS Unit 3, Q1(a)(v) (3 marks): In another part of the investigation, a plan of the tissues in the stem was drawn. Describe how a thin section of a stem could be prepared and viewed using a li
October 2022, AS Unit 2, Q2(a) (1 mark): One water lily leaf has a diameter of 305 cm. Which of the following shows the upper surface area of this leaf? Assume the leaf is circular. Use the formula πr2
October 2022, AS Unit 2, Q2(b) (1 mark): The photograph shows a cross-section of the stem of a water lily. X (Source: © Scenics & Science/Alamy Stock Photo) The structure labelled X contains xylem vess
October 2022, AS Unit 2, Q3(a)(i) (2 marks): The nutrient solutions contain magnesium ions and nitrates. Describe the roles of these inorganic ions in the plants. (2) Magnesium ions Nitrates .
October 2022, AS Unit 2, Q3(a)(ii) (1 mark): Suggest one advantage of the vertical system over the horizontal system. (1)
October 2022, AS Unit 2, Q3(b)(i) (1 mark): Which is the percentage increase in mean fruit firmness between the cherries from the control plants and those from plants treated three times with the higher c
October 2022, AS Unit 2, Q3(b)(ii) (1 mark): Give one conclusion for this investigation. (1)
October 2022, AS Unit 2, Q3(b)(iii) (3 marks): Explain the effect of calcium ion concentration on the firmness of cherry fruits. (3)
October 2022, AS Unit 2, Q4(a)(ii) (2 marks): Explain why boards made from oil-based plastics are not considered sustainable. (2)
October 2022, AS Unit 3, Q3(a)(i) (4 marks): Devise a procedure to provide a valid comparison of the growth of shoots, bulbs and roots of onion plants grown in these three solutions. (4)
October 2022, AS Unit 3, Q3(a)(ii) (2 marks): The graph shows the results of this investigation. 7.0 Key 6.0 double strength 5.0 normal strength 4.0 Mass / g half strength 3.0 2.0 1.0 0.0 shoot bulb root T
October 2022, AS Unit 3, Q3(a)(iii) (3 marks): Describe three conclusions that can be drawn from the results of this investigation. Use the information in the graph and table to support your answer. (3) 1 2
October 2022, AS Unit 3, Q3(a)(iv) (3 marks): Describe the information that is needed to decide if any of the differences seen are statistically significant. . (3)
October 2022, AS Unit 3, Q3(b) (2 marks): The table shows the mineral salts used to make a complete mineral ion solution. Mineral salt formula Mineral salt name KNO3 potassium nitrate Ca(NO3)2 calcium n
October 2022, AS Unit 3, Q3(c) (4 marks): The pH of the soil can affect the uptake of mineral ions by plants. The chart shows the effect of pH on the uptake of some mineral ions. The height of the bar f
June 2022, AS Unit 2, Q3(a)(i) (2 marks): A spherical calabash fruit was cut in half to make two bowls. Each bowl had a radius of 25 cm. Calculate the volume of one bowl to the nearest whole number. Use
June 2022, AS Unit 2, Q3(a)(ii) (2 marks): Explain why bowls made from calabash fruits are a sustainable resource. (2)
June 2022, AS Unit 2, Q3(b)(i) (1 mark): How many of the following statements about sclerenchyma fibres are correct? • they provide support to the plant • they are used to translocate organic solutes •
June 2022, AS Unit 2, Q3(b)(ii) (4 marks): Compare and contrast the structures of phloem sieve tubes and xylem vessels. (4)
January 2022, AS Unit 3, Q2(a)(i) (2 marks): Each of the smallest units on the graticule is 3 × 10−6 m. Calculate the width of the pith cell labeled A in micrometres (μm). (2) Answer μm
January 2022, AS Unit 3, Q2(a)(ii) (2 marks): Name the two types of tissue found in fibres from plant stems. (2) 1 2
January 2022, AS Unit 3, Q2(b)(i) (4 marks): Describe how you could use this apparatus to make a valid comparison of the tensile strength of fibres with different diameters. (4)
January 2022, AS Unit 3, Q2(b)(ii) (4 marks): Some results from this investigation are shown in the table. Diameter / μm Tensile strength / MPa 21 1280 25 830 40 610 43 580 60 390 81 190 84 180 Plot a suita
January 2022, AS Unit 3, Q2(b)(iii) (3 marks): Describe the relationship between the diameter and the tensile strength of these fibres. (3)
January 2022, Unit 6, Q1(a) (6 marks): Describe an experiment to measure the tensile strength of fibres that have been extracted from these plants. (6)
October 2021, AS Unit 2, Q5(b)(i) (3 marks): Calculate the width of the phloem vessel along the line XY in micrometres. Give your answer in standard form. (3) Answer µm
October 2021, AS Unit 2, Q5(b)(ii) (2 marks): Describe the role of phloem. (2)
October 2021, AS Unit 2, Q5(b)(iii) (1 mark): How many of the following statements about mature sclerenchyma fibres are correct? • they contain cellulose microfibrils • they contain pits • they contain cyto
October 2021, AS Unit 2, Q5(c) (3 marks): The roots of plants contain phloem and xylem vessels, as shown in the diagram. epidermis xylem phloem Give three differences between the distribution of phloem
June 2021, AS Unit 2, Q1(a)(iii) (1 mark): Which molecule contains magnesium ions? (1) A calcium pectate B chlorophyll C DNA D starch
June 2021, AS Unit 2, Q1(b)(i) (1 mark): Name one tissue that gives the plant support and is also involved in the transport of water through the plant. (1)
June 2021, AS Unit 2, Q1(b)(ii) (1 mark): Name one fibre that gives the plant support but is not involved in the transport of water through the plant. (1)
June 2021, AS Unit 2, Q4(b)(i) (2 marks): In 2018, a company in Mexico produced 130 000 kg of bioplastic cutlery and straws per month. 40% of the products were straws. Calculate the mass of cutlery prod
June 2021, AS Unit 2, Q4(b)(ii) (2 marks): The use of these plant‑based products is more sustainable than the use of cutlery and straws made from oil‑based plastic. Explain what is meant by the term sust
January 2021, AS Unit 2, Q5(a)(i) (1 mark): Which of the labelled structures is sclerenchyma? (1) A W B X C Y D Z
January 2021, AS Unit 2, Q5(a)(ii) (1 mark): Which of the labelled structures is involved in transporting substances both up and down the plant stem? (1) A W B X C Y D Z
January 2021, AS Unit 2, Q5(a)(iii) (1 mark): Which of the labelled structures is involved in transporting calcium ions from the stem to the leaves? (1) A V B W C X D Y
January 2021, AS Unit 2, Q5(a)(iv) (1 mark): Which of the following may have secondary thickening in the cell walls? (1) A phloem sieve tubes only B phloem sieve tubes and sclerenchyma fibres C xylem vesse
January 2021, AS Unit 2, Q5(b)(i) (2 marks): Explain the importance of magnesium ions to plants. (2)
January 2021, AS Unit 2, Q5(b)(ii) (4 marks): Comment on the results of this investigation. Use the information in the table to support your answer. (4)
January 2021, AS Unit 3, Q2(a)(i) (2 marks): Describe the contents of two more Petri dishes that could be controls for this investigation. (2) Dish 1 Dish 2
January 2021, AS Unit 3, Q2(b)(i) (4 marks): Plot a suitable graph to show the results of this investigation. (4)
January 2021, AS Unit 3, Q2(b)(ii) (3 marks): Explain the difference in duckweed growth in the mineral solution missing nitrate and the mineral solution missing phosphate. Use the information in the table t
January 2021, AS Unit 3, Q2(c)(i) (2 marks): Suggest why counting plants will give an inaccurate result for the growth of duckweed after 14 days. Use the information in the photograph to support your answe
January 2021, AS Unit 3, Q2(c)(ii) (4 marks): Explain how this investigation could be modified to provide an accurate measure of the growth rate of duckweed. (4)
October 2020, AS Unit 2, Q4(a) (3 marks): The diagram shows the structure and composition of a grain of wheat. wheat bran (14%) endosperm (83%) embryo (3%) Wheat bran contains 43% fibre. A grain of whea
October 2020, AS Unit 2, Q4(b) (3 marks): Disposable plates and cutlery can be made from either plant‑based products or from oil‑based plastics. The photograph shows cutlery and a plate made from wheat
January 2020, AS Unit 2, Q6(a)(i) (1 mark): The diagram shows a transverse section through the stem of a plant. Label the diagram to show the position of the xylem and the phloem. (1)
January 2020, AS Unit 2, Q6(a)(ii) (1 mark): Below are some statements about xylem and phloem. • both tissues have a transport function • xylem vessels contain sieve plates • phloem transports polysacchari
January 2020, AS Unit 2, Q6(b)(i) (3 marks): Calculate the percentage decrease in the mean diameter of the fibres from plants in row 2 compared with those from plants in row 1. (3) Answer %
January 2020, AS Unit 2, Q6(b)(ii) (4 marks): Comment on the results of this investigation. Use the information in the table to support your answer. (4)
January 2020, AS Unit 2, Q6(d) (4 marks): Explain how xylem vessels are adapted for support and transport. (4) Support Transport
January 2020, AS Unit 3, Q2(a) (4 marks): Describe a valid method that could be used to compare the breaking force of these fibres. (4)
January 2020, AS Unit 3, Q2(b)(i) (5 marks): Devise a method to determine the cross-sectional area of a fibre, using the following equipment: • a sharp blade • a microscope • a microscope slide and coversl
January 2020, AS Unit 3, Q2(b)(ii) (3 marks): The breaking force and the cross-sectional area were used to determine the tensile strength of fibres from five species of plant. The graph shows the results of
January 2020, AS Unit 3, Q2(b)(iii) (3 marks): The breaking force of a jute fibre is 1.08 newtons. Calculate the cross-sectional area of a jute fibre, using the information in the graph and the following for
June 2019, AS Unit 2, Q1(a)(i) (1 mark): Which letter identifies a xylem vessel? (1) A W B X C Y D Z
June 2019, AS Unit 2, Q1(a)(ii) (1 mark): Which letter identifies a sclerenchyma fibre? (1) A U B V C W D Z
June 2019, AS Unit 2, Q1(b)(i) (1 mark): The concentration of calcium ions is 0.45 mmol dm–3. Plot this concentration on the graph. (1)
June 2019, AS Unit 2, Q1(b)(ii) (3 marks): Explain the importance of each of these ions to the plant. (3)

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