Transport in plants — AS & A Level Biology (9700) questions by topic

Water potentials were measured inside a leaf cell, in the air spaces of the leaf and in the atmosphere. Which values of water potential (Ψ) would allow water to move from the leaf…

Three samples of liquid were taken from different locations in a plant and tested to measure the concentration of four solutes. The results are shown. sample sucrose / mol m⁻³…

A heated band was wrapped around the stem of a plant at a height of 1 m above the ground and left for 10 minutes. How will heating a small section of the stem to 60 °C affect the…

Which row is correct for transpiration? definition of transpiration comparison of water potential --- --- --- A evaporation of water from leaf surfaces higher inside air spaces in…

Which features of companion cells and xylem vessel elements make them suitable for their function? companion cells xylem vessel elements --- --- --- A transport contents of cell…

The diagram shows some root cells with arrows indicating the pathway of water moving from the soil. The water moves through the cell walls only (apoplast pathway), bypassing the…

The graph shows the diameter of a tree trunk at different times. The x-axis shows time of day (00:00 to 00:00 spanning one full day). The y-axis shows diameter of tree trunk in…

The plan diagrams of transverse sections of two plant organs are shown. These are not drawn to scale. The first organ (leaf-like shape) has Q labelling the upper…

A photomicrograph at ×80 magnification shows vascular tissue in longitudinal section. Which tissue is shown? A xylem only B phloem only, transverse section C xylem only,…

Bond R is a bond between water molecules in the xylem. Which type of bond is R and what property does it give to water in the xylem lumen? A R = covalent bond; cohesion in lumen B…

Water and solutes pass through the leaf via the symplast pathway. Which statement about the symplast pathway is correct? A Water moves through the cell walls. B Water moves…

Two plants, K and L, are parasites of other plants. Plant K grows into xylem tissue and plant L grows into phloem tissue. Which substances could plants K and L take from the…

Which statements are correct for the apoplast pathway? 1 Water enters the cell wall. 2 Water moves by osmosis. 3 Water moves from cell wall to cell wall. 4 Water moves through…

Mass flow is the bulk movement of materials from one place to another. Which vessels carry fluids by mass flow? 1 artery 2 phloem sieve tube element 3 vein 4 xylem vessel element…

Which features are present in companion cells and also in phloem sieve tube elements? ribosomes plasmodesmata --- --- --- A present not present B present present C not present…

Phosphate ions are absorbed from the soil solution by roots and are needed for cellular processes throughout plants. Scientists investigated the movement of phosphate ions in…

Fig. 1.1 is a photomicrograph of a transverse section through part of a root of a Ranunculus species. The photomicrograph shows a cross-section of the vascular cylinder with…

L1 is a slide of a stained transverse section through a plant organ. Draw a large plan diagram of a region of the organ on L1 to include the epidermis and two vascular bundles.…

Guard cells are located in the epidermis of the leaves of most plants. When environmental conditions change, this causes changes in guard cells that control the opening and…

Rice, Oryza sativa, can grow in flooded fields. Aerenchyma is a tissue found in the roots of rice. The development of aerenchyma is stimulated by flooding. Scientists grew rice…

The electron micrograph shows a longitudinal section of part of the stem of a plant. The structure labelled X is an elongated cell with a thick, patterned (lignified) wall and no…

Which substance makes xylem vessel walls impermeable to water?

Which row correctly identifies sinks for sucrose transported by mass flow in plants? The columns are 'root storage organ', 'growing leaf bud' and 'growing shoot tip'. (key: tick =…

The diagram shows a transverse section through a transport tissue in a plant. Cell 1 is a small cell adjacent to a larger cell; cell 2 is a large cell with a relatively empty…

Which statement correctly describes the movement of solutes in the symplast pathway?

Which statement helps to explain why water molecules are forced to move through xylem vessel elements as a consequence of transpiration?

Which substances in xylem tissue are impermeable to water and prevent the collapse of the vessels? impermeable to water prevent collapse --- --- --- A cellulose cellulose only B…

The electron micrograph shows a longitudinal section through phloem tissue. [Electron micrograph of a longitudinal section through phloem tissue, showing an elongated sieve tube…

Carrier proteins in the cell surface membranes of companion cells are involved in the transfer of assimilates to phloem sieve tubes. The diagram represents the use of two types of…

The pressure of water vapour inside and outside leaves can be measured. The difference between these pressures is known as the leaf vapour pressure deficit (LVPD). LVPD is one of…

Lignin and suberin are polymers that are present in plant tissues. Describe and explain the roles of lignin and suberin in the transport of water through the roots and stem of a…

Many plants store starch in their roots. The amount of starch present in roots can vary with the seasons. In the summer months, when plants are actively growing, the starch…

K1 is a slide of a stained transverse section through a plant leaf. Fig. 2.1 shows a circular outline of the whole leaf section with a shaded quarter-segment indicating the region…

Stomata in leaves respond to changes in environmental conditions by opening and closing. This regulates carbon dioxide uptake and water loss. Describe the mechanism by which…

Which statement correctly identifies the movement of sucrose and amino acids in plant vascular tissue?

Xylem vessel elements are specialised cells that are adapted for the transport of water. Which statement correctly matches an adaptation of a xylem vessel element to its function?

A student makes an accurate labelled plan diagram of a section of a leaf containing a vascular bundle. Which statement correctly describes part of their plan diagram?

The diagram shows a longitudinal section of a phloem sieve tube with a companion cell. Four positions are labelled A, B, C and D. Label A points to a position within the sieve…

The diagram shows a phloem sieve tube element and a companion cell that are involved in translocation of sucrose. The boundary region between the two cells is labelled with…

Which types of molecules are cotransported into companion cells?

A student drew a plan diagram of some plant tissue. The diagram is shown and it contains a mistake in the way that it is drawn. The diagram shows a curved outer region with three…

Four students have drawn and labelled part of a structure seen on an electron micrograph (a sieve tube element with a companion cell). Which student has labelled their drawing…

The diagram shows some structures used for transport in the phloem. It shows cell Y with an associated companion cell at one end of a phloem sieve tube, and cell Z at the other…

The diagram shows a section through a root of a dicotyledonous plant, with the xylem vessel, Casparian strip, root cell and root hair cell labelled, and a soil particle next to…

The transport of water from the soil solution to the xylem of roots occurs by the apoplast and symplast pathways. Mineral ions can be transported dissolved in water. Describe the…

The leaves of many plants have stomata that show a regular daily rhythm of opening and closing over a period of 24 hours. Explain why it is important for plants to open and close…

Fig. 3.1 is a diagram of an area of phloem tissue from a transverse section through the stem of a squash plant, Cucurbita pepo, showing a companion cell and two sieve tube…

P1 is a slide of a stained transverse section through a plant root. Draw a large plan diagram of the region of the root on slide P1 indicated by the shaded area in Fig. 2.1. Use a…

The Venn diagram shows three overlapping circles for xylem vessel element, companion cell and phloem sieve tube element. Region B is the overlap of xylem vessel element and…

What is the correct term to describe intermolecular hydrogen bonding between water molecules? A adhesion B cohesion C osmosis D diffusion

The diagram shows the outline of a xerophytic leaf that had been left for 45 minutes in different conditions, P and Q. In condition P the leaf is shown flat and open; in condition…

How does sucrose move from chloroplasts to the phloem? 1 diffusion; 2 apoplast pathway; 3 symplast pathway. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

How are companion cells involved in loading sucrose into phloem sieve tube elements? A actively through cotransporter proteins and passively through plasmodesmata B actively…

Which row identifies cells with plasmodesmata? The options are given as a table with a tick for 'plasmodesmata present' and a cross for 'not present' across phloem sieve tube…

Which statements about the apoplast and symplast pathways are correct? 1 In the apoplast pathway, water molecules move through free spaces in the cellulose cell walls of plant…

Where does water evaporate from during transpiration? A intercellular spaces B leaf surface C mesophyll cell walls D stomatal pores

The diagram shows the outline of three xerophytic leaves of the same type in three different conditions, P, R and S. In condition P the leaf is flat and open, layer Y labelled; in…

The photomicrograph shows a transverse section of the leaf of a species of grass that is specially adapted to grow in a dry habitat, with rolled leaves and hair-like structures.…

Which statement supports the theory of active loading of sucrose into companion cells? A The pH decreases in the cell wall of the companion cells compared with the cytoplasm. B…

Which row correctly explains how the structures of phloem sieve tube elements and xylem vessel elements are related to their functions as transport systems? A phloem sieve tube…

Which component of plants is used by the apoplast pathway as water is moved from the soil to the xylem? A Casparian strip B cellulose C endodermis D suberin

Which statements correctly describe transport pathways in dicotyledonous plants? 1 In the symplast pathway, water may move through intercellular spaces. 2 The symplast pathway may…

Plants, such as the tobacco plant, retain very little of the water they take in and the volume of water lost during transpiration is very high. This is because these plants can…

Which changes occur as sucrose is transferred from leaves into phloem sieve tubes to be transported to a sink? A water potential in phloem sieve tubes becomes less negative;…

The graph shown does not have any axis labels; it shows a straight line with a negative gradient starting at a high value on the y-axis and decreasing as the x value increases.…

Fig. 6.1 is a diagram showing the passage of water through the tissues of a flowering plant from the soil to the atmosphere. The arrows show the direction of water movement. The…

Phloem and xylem are specialised tissues involved in the transport of water, ions and assimilates in plants. A photomicrograph of a transverse section of a dicotyledonous stem is…

J1 is a slide of a stained transverse section through a plant leaf. Draw a large plan diagram of the region of the leaf on J1, indicated by the shaded area in Fig. 2.1. Use a…

K1 is a slide of a stained transverse section through a plant root. Draw a large plan diagram of the region of the root on K1 indicated by the shaded region in Fig. 2.1. Use a…

L1 is a slide of a stained transverse section through a plant root. Draw a large plan diagram of the whole section on L1. Use a sharp pencil. Use one ruled label line and label to…

N1 is a slide of a stained transverse section through a plant stem. Draw a large plan diagram of the region of the stem on N1 indicated by the shaded area in Fig. 2.1. Use a sharp…

M1 is a slide of a stained transverse section through a plant leaf. Draw a large plan diagram of the region of the leaf on M1 indicated by the shaded region in Fig. 2.1. Use a…

The plan diagram of a transverse section through a dicotyledonous plant stem was drawn by a student. They had stained the section with a chemical that stains lignin. The diagram…

Which routes must water travel through in a plant, using the symplast pathway? 1 from soil into root hair cell vacuoles 2 from soil into root hair cell walls 3 from root hair cell…

A plant leaf seen in transverse section with a microscope shows the features listed: a thick waxy cuticle on the upper surface, sunken stomata on the lower surface, and a rolled…

What occurs as carbohydrate is taken out of a sink into a phloem sieve tube element? water potential in phloem sieve tube element becomes volume of liquid in phloem sieve tube…

Four students sketched diagrams of the apoplast pathway and the symplast pathway through root cells towards the xylem. Each diagram shows a row of cells with a Casparian strip in…

The photomicrograph shows some xerophytic adaptations in leaf tissue. Structure 1 points to hairs on the leaf surface, structure 2 points to a rolled leaf edge, and structure 3…

Which processes are required for the transfer of assimilates from a source cell into a phloem sieve tube? A active transport, facilitated diffusion and simple diffusion B active…

When sucrose is loaded into the phloem it has to travel from mesophyll cells to a companion cell and then into the phloem. Which row shows the relative concentrations of sucrose…

Which feature of transport in plants is correct for xylem and phloem? A It is passive. B It occurs by mass flow. C It occurs from source to sink. D It occurs only in one direction.

Which statement about xylem vessel elements is correct? A Hollow vessels enable the constant movement of water up and down a plant. B Pits enable the movement of water into…

Ammonium ions, NH4+, can enter the xylem of plant roots by two pathways. • In the apoplast pathway, ammonium ions move through cell walls until this pathway is blocked by the…

Which row correctly shows processes required for the movement of water from a root hair cell to the atmosphere? cohesion diffusion evaporation --- --- --- --- A ✓ ✓ ✓ B ✗ ✓ ✗ C ✓…

Plants have specialised cells for the efficient transport of assimilates. Table 3.1 shows some of the features of two different types of cell found in plant tissue, which are…

Water that is absorbed from the soil solution by the roots of a plant enters xylem vessels and is transported to the leaves and buds. Fig. 6.1: a spider diagram listing four…

In flowering plants, transport of assimilates occurs in phloem tissue between sources and sinks. Explain why a root can be a source and a sink.

K1 is a slide of a stained transverse section through a plant leaf. Draw a large plan diagram of the whole leaf on K1. Use a sharp pencil. Use one ruled label line and label to…

M1 is a slide of a stained transverse section through a plant leaf. Draw a large plan diagram of the region of the leaf on M1 indicated by the shaded area in Fig. 2.1 (the midrib…

L1 is a slide of a stained transverse section through a plant stem. Draw a large plan diagram of the region of the stem on L1 indicated by the shaded area in Fig. 2.1 (a quarter…

N1 is a slide of a stained transverse section through a plant stem. Draw a large plan diagram of the region of the stem on N1 indicated by the shaded area in Fig. 2.1 (a corner…