Lesson 4.4.3

4.4.3 Cellulose microfibrils and xylem, phloem and sclerenchyma Quiz: Pearson Edexcel Biology A (Salters-Nuffield), Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.4.3, Cellulose microfibrils and xylem, phloem and sclerenchyma: 20 multiple choice questions for the Pearson Edexcel Biology A (Salters-Nuffield) (9BI0), Unit 4: Biodiversity and Natural Resources, written with Revision Ninja.

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The 20 questions

  1. Which tissue transports water and mineral ions through a plant stem?

    • Xylem
    • Epidermis
    • Phloem
    • Sclerenchyma

  2. Which tissue carries organic solutes such as sucrose?

    • Cortex
    • Xylem
    • Phloem
    • Sclerenchyma

  3. Xylem vessels are best described as:

    • Living cells with many plasmodesmata only
    • Dead cells with no cell wall
    • Living cells with cytoplasm and sieve plates
    • Dead, hollow cells with thick lignified walls

  4. Sieve tubes in phloem have:

    • Sieve plates between their end walls
    • No cytoplasm and no membrane at maturity
    • Lignified secondary walls, like xylem vessels
    • Pits only, with no end walls between cells

  5. Sclerenchyma fibres are mainly involved in:

    • Photosynthesis
    • Support
    • Active uptake of nitrate
    • Gas exchange

  6. Secondary thickening of xylem vessels and sclerenchyma is important because it:

    • Adds mechanical strength to support the plant
    • Prevents starch being stored in the cell
    • Enables photosynthesis in the stem
    • Stops water from entering the cell

  7. Which phloem cells are living cells that support adjacent sieve tube elements?

    • Guard cells
    • Xylem parenchyma
    • Sclerenchyma fibres
    • Companion cells

  8. Sieve tubes are living cells with few organelles. Which feature explains how sucrose moves through them?

    • Sclerenchyma fibres pump sap upwards
    • Sieve plates allow bulk flow of sap
    • Xylem vessels pump sucrose along the stem
    • Lignin in the sieve walls transports sugars

  9. In a light microscope section of stem, a cell with thick, lignified walls and no cytoplasm is:

    • A companion cell
    • A sieve tube
    • A xylem vessel
    • A palisade cell

  10. Thick-walled cells with no cytoplasm are seen near the outside of a stem section. Which tissue is most likely?

    • Xylem vessels in the centre
    • Guard cells
    • Sclerenchyma fibres
    • Phloem sieve tubes

  11. A ring of bark is removed to cut the phloem of a stem. What is the most likely effect above the cut?

    • Water stops moving up the xylem immediately
    • Photosynthesis stops in every leaf
    • Sugar builds up above the ring, starving the roots
    • Lignin in the xylem is destroyed

  12. A stem bends in wind. Which structure most directly resists bending?

    • Sclerenchyma fibres with thick, lignified walls
    • Root hairs on the epidermis absorbing water
    • Companion cells beside the phloem sieve tubes
    • Sieve tubes carrying sucrose through the phloem

  13. Which statement comparing xylem vessels and sieve tubes is correct?

    • Both have sieve plates between their end walls
    • Both carry sucrose to the roots
    • Both are living cells at maturity
    • Xylem vessels are dead; sieve tubes are living

  14. Why do cellulose microfibrils in secondary walls contribute to the physical properties of xylem?

    • Layers of microfibrils resist collapse under tension
    • They allow photosynthesis to occur in the xylem
    • They make the wall permeable to all solutes equally
    • They are digested by amylase during transport

  15. A student predicts that a stem with more sclerenchyma resists bending better but does not transport more water. Which investigation tests this?

    • Counting chloroplasts in the leaves only
    • Measuring the pH of the leaf surface
    • Measuring bending and water flow in each stem
    • Staining starch in the roots only

  16. Why do sieve tube elements depend on companion cells?

    • Companion cells make the lignin needed for sieve plates
    • Companion cells carry water upwards through the stem
    • Companion cells replace the xylem during water transport
    • They lack a nucleus, so companion cells support them

  17. Xylem vessels are under tension during transpiration. Which feature of their walls prevents collapse?

    • Plasmodesmata that let water drain between cells
    • Thick, lignified secondary walls that resist collapse
    • Sieve plates that hold the vessel open
    • Starch granules that absorb the pressure

  18. Plants from a windy site have more lignified xylem than plants from a sheltered site. What is the best interpretation?

    • Lignin increases sucrose loading into the phloem
    • Extra support against wind-induced bending
    • The plant transports less water in all conditions
    • The plant is a phloem-only species

  19. Two stems of equal mass: stem A has more sclerenchyma near the outside and stem B has more xylem in the centre. Which statement is best?

    • A resists bending better and B transports water better
    • B resists bending better than A
    • Both stems have identical mechanical and transport properties
    • A transports more water than B

  20. Why do sieve plates matter for translocation?

    • They block flow completely to store sugars
    • They have pores that let sap flow between sieve tube elements
    • They filter out sucrose before it reaches the leaves
    • They store starch for later use by the plant

All Pearson Edexcel Biology A (Salters-Nuffield) quizzes