Topic 7 Practice Paper: Transport in plants — question paper

Section A: Multiple-choice questions[10 marks]

Choose one answer for each question. Each question is worth 1 mark.

1. 1

   Which substances are transported in the phloem?

   1. AWater and mineral ions
   2. BOxygen and carbon dioxide
   3. CSucrose and amino acids
   4. DStarch and cellulose
   ( )
2. 2

   Water evaporates from a leaf mainly from

   1. Athe stomata
   2. Bthe surfaces of mesophyll cells
   3. Cthe waxy cuticle
   4. Dthe xylem
   ( )
3. 3

   Which change would SLOW the rate of transpiration?

   1. ARaising the temperature
   2. BIncreasing wind speed
   3. COpening more stomata
   4. DIncreasing humidity
   ( )
4. 4

   The stain in a transpiration experiment is found only in the xylem because

   1. Aphloem blocks the stain
   2. Bstains cannot enter phloem
   3. Cwater travels only in the xylem
   4. Dthe stain was carried by active transport
   ( )
5. 5

   In a stem vascular bundle of a non-woody dicotyledon,

   1. Axylem is on the inside and phloem on the outside
   2. Bphloem is on the inside
   3. Cxylem is on the outside
   4. Dboth tissues are in the root cortex
   ( )
6. 6

   Which feature of a root hair cell speeds water uptake?

   1. AThick lignin walls
   2. BA long extension giving a large surface area
   3. CNo nucleus
   4. DMany chloroplasts
   ( )
7. 7

   In transpiration pull, the upward movement works because

   1. Aroots pump water actively
   2. Bgravity assists the flow
   3. Cphloem pushes from below
   4. Dwater molecules attract each other, holding the column together
   ( )
8. 8

   A plant cell loses more water than it gains during a drought. The cell becomes

   1. Aturgid
   2. Bfilled with sap under pressure
   3. Cflaccid and then plasmolysed
   4. Dburst
   ( )
9. 9

   A part of a plant that RELEASES sucrose into the phloem is called a

   1. Asource
   2. Bsink
   3. Cstoma
   4. Dlumen
   ( )
10. 10

    Why does a mature storage bulb act as a source in spring?

    1. AIt photosynthesises with its green skin
    2. BIt releases stored sucrose to power new shoots
    3. CIt stores the sucrose made by new leaves
    4. DIt carries water to the roots
    ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided.

1. 11

   A student sets up a potometer with a leafy shoot. The water column moves 5.0 cm³ in 2 hours in still air, and 12.0 cm³ in the next 2 hours when a fan is switched on.

   1. (a)

      Calculate the rate of water uptake in still air, in cm³ per hour.

      rate =cm³/h[1]
   2. (b)

      Calculate the percentage increase in the rate when the fan is on.

      [2]
   3. (c)

      Explain the increase, referring to water vapour and diffusion gradients.

      [2]
   4. (d)

      State one other factor the student should keep constant, and one reason the potometer estimates transpiration rather than measuring it directly.

      [1]
2. 12

   Describe the journey of a water molecule from the soil to the air outside a leaf.

   1. (a)

      State the pathway of the water from a root hair cell to a mesophyll cell.

      [2]
   2. (b)

      Name the process by which the water enters the root hair cell and state one other substance entering there, with its process.

      [2]
   3. (c)

      Describe what happens to most of the water that reaches a mesophyll cell.

      [2]
   4. (d)

      Name the force that pulls the water column up the xylem.

      [1]
3. 13

   An apple tree’s fruits grow and ripen from mid-summer, and the tree drops its leaves in autumn. In early spring, before the leaves open, buds use stored carbohydrate to grow.

   1. (a)

      For mid-summer, identify a source and a sink in the tree, with reasons.

      [2]
   2. (b)

      For early spring, explain why the stored carbohydrate in the tree acts as a source.

      [2]
   3. (c)

      Name the tissue transporting the sucrose, and state one other substance it carries.

      [2]
   4. (d)

      State one structural feature of mature xylem vessels and explain how it helps them withstand transpiration pull.

      [1]