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Topical›Biology 9700›Transport in plants›Transport mechanisms›Paper 1

Transport mechanisms — Paper 1 · A Level Biology 9700

7.2· 340 questions · 340 marks · 408 min · 2004–2025· Multiple choice

Every Cambridge A Level Biology Paper 1 question on transport mechanisms, laid out as 109 A4 pages with the mark scheme below. Nothing is left out. Free to read, no account.

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Question 1: A region of a stem of a plant is heated to kill the cells in the living vascular tissues. How will this treatment affect the transport bet…Question 2: Some soil-borne fungi cause wilting in crop plants by growing within the xylem vessels. Which process will be directly affected by these fu…Question 3: The movement of water through the vascular tissue in plants relies on which property of water? A changes in density with temperature B good…Question 4: The graph shows the relationship between the loss of water vapour through stomata and an environmental factor. loss of water vapour environ…1 / 109
Question 5: What is responsible for the movement of water up xylem vessels in plants? A active loading of water against the water potential gradient in…Question 6: A water potential gradient causes water to move through xylem. Which process is mainly responsible for this water potential gradient? A cap…Question 7: During transpiration, what is the site of evaporation of water in the leaves? A air spaces B mesophyll cell walls C stomata D walls of xyle…Question 8: The diagram represents the phloem pathway, with adjacent cells, from leaf to root in a plant. 2 leaf cell 1 chloroplast parenchyma cell nuc…2 / 109
Question 9: The diagram represents a transverse section through a part of the root of a plant. cortex xylem soil water Which values of water potential …Question 10: Translocation in plants moves sucrose from sources to sinks. Which of the following can be a source and which a sink? source sink A germina…3 / 109
Question 11: A large number of aphids were used to collect samples of the contents of the sieve tubes of a tomato plant. sieve tube element sample taken…4 / 109
Question 12: The diagram shows a dendrograph fixed to a tree. The dendrograph records changes in the diameter of the tree. Some results are shown on the…Question 13: Which features of xerophytes reduce water loss by transpiration? rolled leaves | swollen leaves | sunken stomata | thick waxy cuticle 0 O…Question 14: Four solutions, with different water potentials are listed. 1 endodermal cell solution 2 root hair cell solution 3 soil water solution 4 so…5 / 109
Question 15: Which feature of a root hair cell is not an adaptation for water uptake from the soil solution? A lack of a waxy cuticle B large numbers of…Question 16: The diagram shows a model to demonstrate the mass-flow hypothesis of translocation. W water concentrated dilute sucrose solution Y X Z sucr…Question 17: What is the sequence of events in the translocation of assimilates? A active loading of sucrose into sieve elements via companion cells at …Question 18: What occurs in the sieve tube elements of a photosynthesising leaf and an actively growing root? sieve tube elements in leaf sieve tube ele…6 / 109
Question 19: Some soil-borne fungi cause wilting in crop plants by growing within the xylem vessels. Which process will be directly affected by these fu…Question 20: What occurs in the sieve tube elements of a photosynthesising leaf and an actively growing root? sieve tube elements in leaf sieve tube ele…Question 21: Some soil-borne fungi cause wilting in crop plants by growing within the xylem vessels. Which process will be directly affected by these fu…Question 22: Some soil-borne fungi cause wilting in crop plants by growing within the xylem vessels. Which process will be directly affected by these fu…Question 23: What occurs in the sieve tube elements of a photosynthesising leaf and an actively growing root? sieve tube elements in leaf sieve tube ele…7 / 109
Question 24: The diagram shows some adjacent cells from the root of a plant. Which is the apoplastic pathway of water movement? A B C DQuestion 25: What determines the rate of water movement from the roots to the leaves? A absorption of water through the root hair cells B development of…Question 26: Which processes are involved in transpiration? 1 the diffusion of water vapour from stomata 2 the mass flow of water through the xylem 3 th…8 / 109
Question 27: Water passes across leaf tissues by different routes as a result of • differences in water potential • the pull transmitted by cohesive for…9 / 109
Question 28: The diagram shows the water potential (Ψ) in some plant cells and in their environment. cell 1 cell 2 Ψ = Ψ = cell 3 – 5 kPa Ψ = – 7 kPa – …Question 29: During transpiration, what is the site of evaporation of water in the leaves? A air spaces B guard cell walls C mesophyll cell walls D stom…Question 30: The photomicrograph shows a vascular bundle. 1 3 2 Which describes the relationship of water potential in the labelled cells? A cell 3 less…10 / 109
Question 31: The diagram represents the movement of water through a plant. 3 water vapour is lost from leaves 2 water passes 2 water passes 2 water …Question 32: Which processes are involved in transport in both phloem and xylem? 1 diffusion 2 mass flow 3 osmosis A 1, 2 and 3 B 1 and 2 only C 1 and 3…11 / 109
Question 33: The graph shows the results of measuring the concentration of sucrose in the xylem, phloem and leaves of a plant during 24 hours. phloem su…Question 34: Water that is present inside a root hair cell may leave the cell and pass to the xylem. Through which pathway must the water travel? A apop…12 / 109
Question 35: The diagram represents the movement of water through a plant. 3 water vapour is lost from leaves 2 water passes 2 water passes 2 water …Question 36: The photomicrograph shows a vascular bundle. 1 3 2 Which describes the relationship of water potential in the labelled cells? A cell 3 less…13 / 109
Question 37: During transpiration, what is the site of evaporation of water in the leaves? A air spaces B guard cell walls C mesophyll cell walls D stom…Question 38: In which combination of environmental conditions are the stomata of a plant most likely to close? atmospheric soil water wind humidity pote…Question 39: The diagram shows the tissues involved in the transport of sucrose in a plant. Where is the highest concentration of sucrose? phloem sieve …14 / 109
Question 40: Which evidence supports the cohesion-tension theory for the movement of water in flowering plants? 1 When the rate of transpiration of a tr…Question 41: Which evidence supports the cohesion-tension theory for the movement of water in flowering plants? 1 When the rate of transpiration of a tr…Question 42: In which combination of environmental conditions are the stomata of a plant most likely to close? atmospheric soil water wind humidity pote…15 / 109
Question 43: The diagram shows the tissues involved in the transport of sucrose in a plant. Where is the highest concentration of sucrose? phloem sieve …Question 44: During transpiration, from where does the evaporation of water occur? A intercellular spaces B leaf surface C mesophyll cell walls D stomat…Question 45: The diagram shows a model to demonstrate the mass flow hypothesis of translocation. W water concentrated dilute sucrose solution Y X Z sucr…16 / 109
Question 46: The graph shows stomatal opening and closing in the leaves of a species of Pelargonium, during a 24 hour period. 100 light dark light 80 pe…Question 47: When transpiration is at a maximum rate, tree trunks decrease in diameter. Which statement explains this? A There is decreased suction pres…Question 48: Which statement explains how mass flow arises in sieve tube elements? A Sucrose actively loaded into sieve tube elements decreases the wate…Question 49: Which row identifies the tissue that contains the Casparian strip and the molecule forming this strip? tissue molecule A cortex lignin B en…17 / 109
Question 50: Which of the following are included in the apoplast pathway? 1 living components 2 plant vacuoles 3 cell walls 4 xylem vessels A 3 only B 1…Question 51: Which statement explains why the circumference (girth) of a tree is less in the middle of the day than at night? A Mineral uptake by the ro…18 / 109
Question 52: Sucrose is transported in solution in the phloem of plants. Transport takes place from sources to sinks. The process depends on differences…Question 53: During transpiration, from where does the evaporation of water occur? A intercellular spaces B leaf surface C mesophyll cell walls D stomat…Question 54: When transpiration is at a maximum rate, tree trunks decrease in diameter. Which statement explains this? A There is decreased suction pres…19 / 109
Question 55: The graph shows stomatal opening and closing in the leaves of a species of Pelargonium, during a 24 hour period. 100 light dark light 80 pe…Question 56: Which statement explains how mass flow arises in sieve tube elements? A Sucrose actively loaded into sieve tube elements decreases the wate…Question 57: The diagram shows a model to demonstrate the mass flow hypothesis of translocation. W water concentrated dilute sucrose solution Y X Z sucr…20 / 109
Question 58: The diagram shows a model which can be used to demonstrate mass flow. tube T concentrated X Y dilute sucrose sucrose solution solution wate…Question 59: Which of the following statements explain why a stem is both cut and connected to a potometer under water? 1 To prevent plasmolysis of xyle…Question 60: What is correct about the uptake and transport of water in plants? 1 water transported by the symplast pathway enters root hair cells down …21 / 109
Question 61: Which combination of conditions increases the rate of transpiration in plants? light intensity humidity temperature A high high low B high …Question 62: Which statement explains why sucrose, rather than glucose, is transported by phloem? A Sucrose can pass through plant cell surface membrane…Question 63: Which correctly matches the structure and function of sieve tube elements? structure function A cellulose cell wall with no lignin to preve…Question 64: How do single-celled organisms survive without a specialised transport system? A Their cell surface membranes are totally permeable. B They…22 / 109
Question 65: The photomicrograph shows a transverse section of a leaf. Which cell has the least negative water potential? C B D AQuestion 66: What occurs during the movement of water through the apoplast pathway? 1 water enters cell wall 2 water enters cytoplasm through plasma mem…Question 67: The loading of sucrose into companion cells involves a number of processes listed below. Which is an active process? A the movement of H+ i…Question 68: Which statement concerning transpiration is correct? A On a humid day, the water potential gradient between the intercellular air space and…23 / 109
Question 69: The diagram shows three xerophytic leaves of the same type in three different conditions, P, R and S. layer X X X P R S Which description o…Question 70: The diagram shows how sucrose is loaded into a sieve tube element. companion cell sieve tube element 1 hydrogen ions move out of the compan…Question 71: Halophytes are plants that can survive in regions where they are regularly exposed to sea water. Sea water has a water potential of approxi…24 / 109
Question 72: The diagram shows part of a transverse section of a leaf. Where does evaporation of water occur during transpiration? A D C BQuestion 73: A potometer can be used to measure transpiration rates in a plant. Why is the plant stem cut under water before attaching to the potometer?…Question 74: Three solutions, with different water potentials (ψ) are listed. 1 cortex cell solution 2 endodermal cell solution 3 root hair cell solutio…25 / 109
Question 75: The statements describe some of the properties of water. 1 requires a lot of heat energy to evaporate 2 retains a lot of heat energy 3 is a…Question 76: Which row is correct? needs energy from transfers heat energy carries assimilates ATP A translocation mass flow xylem vessel element B tran…Question 77: An investigation was carried out into the effect of light intensity on the rate of transpiration. All other variables were standardised. A …26 / 109
Question 78: Different substances, such as sucrose and amino acids, can move in different directions in the phloem sieve tubes. Which statement explains…Question 79: Which feature of a plant cell is an adaptation for water uptake from the soil solution? A waxy cuticle B large numbers of mitochondria C lo…Question 80: A student used a potometer to measure the rate of water loss from a plant by transpiration. The internal diameter of the capillary tube and…Question 81: Which feature of xylem vessel elements helps the cohesion of water? A lignin forms an incomplete secondary wall B new vessels carry extra w…27 / 109
Question 82: What determines the rate of water movement from the roots to the leaves? A absorption of water through the root hair cells B development of…Question 83: The photomicrograph shows a transverse section through a leaf. ×50 Which features of a xerophytic leaf are visible in this section? 1 sunke…Question 84: What is transpiration and which advantage does it give to a plant? transpiration advantage to a plant A evaporation of water maintains the …Question 85: What occurs in the sieve tube elements of a photosynthesising leaf and an actively growing root? sieve tube elements in leaf sieve tube ele…28 / 109
Question 86: What occurs in the apoplast and symplast pathways? water enters water moves from water enters cytoplasm through cell to cell through vacuol…Question 87: Some fungi cause wilting in crop plants by growing within the xylem vessels. Which process will be directly affected by these fungi? A cohe…Question 88: Which processes are involved in transpiration? 1 the diffusion of water vapour from stomata 2 the mass flow of water through the xylem 3 th…29 / 109
Question 89: The graph shows the results of using a potometer to measure the effect of wind speed on the rate of water loss in a plant. 30 25 20 rate of…Question 90: Land flooded by the sea is not suitable for growing plants after the salty flood water has drained away. Which values of water potential in…Question 91: What is the role of ATP in a companion cell when sucrose is loaded into a sieve tube element? A moving sucrose into the sieve tube element …30 / 109
Question 92: Which feature of xylem vessel elements helps adhesion during transpiration? A lignin forms an incomplete secondary wall B new vessels carry…Question 93: The diagram represents part of the phloem pathway, with adjacent cells, from leaf to root in a plant. 2 leaf cell 1 chloroplast parenchyma …Question 94: Which xerophytic adaptations reduce the water potential gradient? 1 rolled leaves 2 hairy leaves 3 sunken stomata 4 fewer stomata 5 fleshy …31 / 109
Question 95: In which combination of environmental conditions are the stomata of a plant most likely to close? atmospheric soil water wind humidity pote…Question 96: What changes occur to the water potential and the volume of liquid in the phloem when carbohydrate is moved into a sink? water potential vo…Question 97: Some plant species can take up heavy metal contaminants that are dissolved in soil water and then transport them within the plant. Within p…Question 98: What is the main function of a companion cell in phloem tissue? A providing cytoplasmic contact with the sieve tube element for loading B p…Question 99: How does sucrose move from chloroplasts to the phloem? 1 mass flow 2 apoplast pathway 3 symplast pathway A 1, 2 and 3 B 1 and 2 only C 1 an…32 / 109
Question 100: A large number of aphids were used to collect samples of the contents of the sieve tube elements of a tomato plant. sieve tube element samp…33 / 109
Question 101: A leafy shoot was attached to a potometer and exposed to a variety of conditions. The time taken for the meniscus to move 50 mm along the c…Question 102: How will the root pressure in a plant be affected by waterlogged soil? A It will not be affected. B It will decrease due to a lack of oxyge…Question 103: Which processes occur in the vascular tissue in leaves and in roots? in leaves in roots A sucrose enters phloem water passes from phloem an…34 / 109
Question 104: The diagram shows the water potential (Ψ) in some plant cells and in their environment. cell 1 cell 2 Ψ = Ψ = cell 3 – 5 kPa Ψ = – 7 kPa – …Question 105: A region of a plant containing the vascular tissue is treated with a metabolic poison. How will this treatment affect the transport betwee…Question 106: A tissue composed of plasmolysed plant cells was put into distilled water. The graph shows how the mean cell volume changes with time. X me…35 / 109
Question 107: The diagram shows a vascular bundle from the stem of a plant. 3 2 1 Which row describes the functions of the labelled cells? transports tra…Question 108: Which changes to the water potential and the volume of liquid in the phloem occur when amino acids are moved into a sink from phloem sieve …36 / 109
Question 109: What is the sequence of events in the translocation of sucrose? A active loading of sucrose into sieve elements at the source, increased hy…Question 110: Where does water evaporate from during transpiration? A inside the guard cells B the outer surface of the epidermal cell layer C the sub-st…Question 111: Which changes to the water potential and the volume of liquid in the phloem occur when amino acids are taken out of a sink in a phloem siev…Question 112: Which force holds water molecules on the surface of cell walls? A adhesion B capillarity C cohesion D surface tensionQuestion 113: The statements are about the properties of water. 1 requires a lot of heat to evaporate 2 holds a lot of heat 3 is able to form hydrogen bo…37 / 109
Question 114: Which changes to the water potential and the volume of liquid in the phloem occur when amino acids are moved into a phloem sieve tube at a …Question 115: Which feature of transport in xylem depends on the use of energy? A mass flow of water to the leaves B osmosis of water into xylem C uptake…Question 116: By which process does sucrose move through phloem sieve tube elements? A active transport B diffusion C facilitated diffusion D mass flowQuestion 117: The diagram shows the results of an experiment using leaves with the same surface area from two different species. Each leaf was left on a …38 / 109
Question 118: Which description of the movement of water through a leaf is not correct? A Water evaporates into an air space from the higher water potent…Question 119: Which changes to the water potential and the volume of liquid in the phloem occur when carbohydrate is taken out of a root into phloem siev…Question 120: What is the role of the Casparian strip? A to act as a site for active transport of ions into the xylem B to increase root pressure, increa…Question 121: Sucrose is loaded into companion cells and phloem sieve tube elements by active transport and diffusion using transport proteins and plasmo…39 / 109
Question 122: Which changes to the water potential and the volume of liquid in the phloem occur when sucrose is transferred from leaves into phloem sieve…Question 123: The diagram shows the results of an experiment using leaves with the same surface area from two different species. Each leaf was left on a …40 / 109
Question 124: The photomicrograph shows a transverse section of a leaf. Which cell has the least negative water potential? C B D AQuestion 125: The diagram shows the results of an experiment on transpiration using two different leaves. Each leaf was left on a balance in daylight in …Question 126: Which processes are involved in the transport of sucrose in plants? 1 active transport 2 mass flow 3 osmosis A 1, 2 and 3 B 1 and 2 only C …41 / 109
Question 127: Which changes to the water potential and the volume of liquid in the phloem occur when carbohydrate is moved from phloem sieve tubes into a…Question 128: Which statement describes movement through a plant in the apoplast pathway? A Water moves through the cell walls. B Water moves through the…Question 129: Which changes to the water potential and the volume of liquid in the phloem occur when sucrose is moved from the phloem sieve tube to an ac…42 / 109
Question 130: The diagram shows the results of an experiment using leaves with the same surface area from two different species of plant. Each leaf was l…Question 131: Which evidence supports the cohesion-tension theory for the movement of water in flowering plants? 1 When the rate of transpiration of a tr…Question 132: Water that is present inside a root hair cell may leave the cell and pass to the vascular tissue. Through which route must the water travel…43 / 109
Question 133: What is a correct definition of the term transpiration? A diffusion of water from intercellular air spaces to the atmosphere where it evapo…Question 134: Which changes to the water potential and the volume of liquid in the phloem sieve tube element occur when sucrose is moved from a photosynt…Question 135: Which statement supports the theory of active loading of sucrose into companion cells? A The pH decreases in the cell wall of the companion…Question 136: The graph shows the diameter of a tree trunk at different times. X Z diameter of tree trunk Y / arbitrary units 24:00 12:00 24:00 time of d…44 / 109
Question 137: Some plant species can take up toxic heavy metal ions that are dissolved in water in the soil. These ions accumulate in the aerial parts of…Question 138: The diagram shows the results of an experiment on transpiration using two different leaves. Each leaf was left on a balance in daylight in …45 / 109
Question 139: Which statement about the transport of sucrose is correct? A ATP synthesised by mitochondria of companion cells provides the energy to move…Question 140: During transpiration, what is the site of evaporation of water in the leaves? A air spaces B guard cell walls C mesophyll cell walls D stom…46 / 109
Question 141: Water passes across leaf tissues by different routes as a result of: ● differences in water potential ● the pull transmitted by cohesive fo…Question 142: Which factors contribute to the increase in transpiration rate when the temperature rises? 1 concentration of water molecules increases in …47 / 109
Question 143: ATP is used in companion cells to provide the energy for loading a sieve tube element with sucrose. How does the co-transporter mechanism u…Question 144: Which changes to the water potential and the volume of liquid in the phloem sieve tube element occur when sucrose is moved from the phloem …Question 145: Which changes to the water potential and the volume of liquid in the phloem occur when carbohydrate is taken out of a sink into a phloem si…48 / 109
Question 146: A dendrograph records changes in the diameter of a tree. The diagram shows a dendrograph fixed to a tree. Some results are shown on the cha…Question 147: Different substances, such as sucrose and amino acids, can move in different directions in the phloem sieve tube elements. Which statement …Question 148: Which describes possible mechanisms by which sucrose is transferred from a mesophyll cell into a companion cell? 1 co-transport with the ac…49 / 109
Question 149: Which statements about water movement in plants are correct? 1 Water cannot pass through cellulose. 2 Water cannot pass through lignin. 3 W…Question 150: The diagrams show transverse sections of parts of a plant. leaf stem root 3 1 4 5 6 2 In the transverse sections, which tissues transport w…50 / 109
Question 151: Which diagram represents the effect of atmospheric humidity on the rate of transpiration? A B rate of rate of transpiration transpiration h…Question 152: Which combination of features is characteristic of a phloem sieve tube element as it unloads into a sink? lignification of water potential …Question 153: Which statements correctly describe transport pathways in dicotyledonous plants? 1 In the symplast pathway, water may move through intercel…Question 154: Which feature of transport in plants is correct for both xylem and phloem? A It is passive. B It occurs by mass flow. C It occurs from sour…51 / 109
Question 155: What is the main function of a companion cell in phloem tissue? A providing cytoplasmic contact with the sieve tube element for loading B p…Question 156: Sucrose moves from a phloem sieve tube element into a root cell. Which changes to the water potential and the volume of liquid in the phloe…Question 157: Which statements about water movement in plants are correct? 1 Water can pass through cellulose cell walls. 2 Water can pass through lignif…Question 158: The photomicrograph is a transverse section of a leaf. 5 4 1 3 2 Which features are characteristic of xerophytes? A 1, 3, 4 and 5 B 1, 2 an…52 / 109
Question 159: A maize crop is successfully growing in a field in which the water potential of the soil is – 40 KPa. What is the most likely water potenti…Question 160: The graph shows the loss of mass in a potted plant due to transpiration. X mass / g time / minutes What could have occurred at point X on t…Question 161: An aphid, such as a greenfly, uses a tubular mouthpart called a stylet to feed on nutrients in the plant. It inserts the stylet through the…Question 162: Which statement correctly describes transport pathways in dicotyledonous plants? A In the apoplast pathway, water may move through plasmode…53 / 109
Question 163: The diagrams show transverse sections of parts of a plant. leaf stem root Suen - , Oe bet 6 In the transverse sections, which tissues tr…Question 164: The statements are descriptions of how water moves across the root to the xylem vessel elements in plants. 1 Water enters the intercellular…54 / 109
Question 165: The diagram shows the tissues involved in the transport of sucrose in a plant. Where is the highest concentration of sucrose? phloem sieve …Question 166: Which features adapt root hair cells for efficient absorption of water? 1 a large number of mitochondria 2 a large number of protein carrie…Question 167: What contributes to the movement of water through the xylem vessel elements? A cohesion of water molecules through hydrogen bonding B ion m…55 / 109
Question 168: The diagram shows a xerophytic leaf in different conditions, P and Q. X X P Q Which statements about the cells in layer X of the leaf in ea…Question 169: What are features that adapt root hair cells for efficient uptake of mineral ions? 1 a large number of mitochondria 2 a large number of pro…Question 170: The transverse sections of two plant organs are shown. S Q T R Which pair of tissues contains proton pumps? A Q and S B Q and T C R and S D…56 / 109
Question 171: Measurements of the stem of a young tree showed that the diameter varied slightly. It decreased during the day and increased during the nig…Question 172: Which of these statements correctly describe transport pathways in dicotyledonous plants? 1 In the apoplast pathway, water may move through…Question 173: 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 tub…Question 174: Amino acids move from a phloem sieve tube element into a root cell. Which changes to the water potential and the volume of liquid in the ph…57 / 109
Question 175: The table shows the volume of water taken up over a 10 minute period for two species of plant, X and Y. water uptake / mm3 time / minutes X…Question 176: The diagrams show transverse sections of parts of a plant. Transport tissues are labelled 1 to 6. leaf stem root 3 1 4 5 6 2 Which row show…Question 177: What will increase the rate of transpiration? 1 increasing the humidity 2 increasing the light intensity 3 decreasing the temperature 4 dec…58 / 109
Question 178: Which properties of water are important for transport in xylem? 1 cohesion 2 adhesion 3 high energy requirement for evaporation 4 good solv…Question 179: What is a function of the hairs (trichomes) on xerophytic leaves? A adding a waterproof layer B protecting the stomata C reducing the surfa…Question 180: Which features of companion cells are essential to their function? 1 They are connected by plasmadesmata to the sieve tube elements. 2 They…Question 181: What is the role of ATP in a companion cell when sucrose is loaded into a sieve tube element? A moving sucrose into the sieve tube element …Question 182: A potometer was used to measure the transpiration rate of a leafy shoot. What could be the correct units? A cm min B cm2 min–1 C cm3 g–1 mi…Question 183: Which combination of features is characteristic of a phloem sieve tube element as it is loaded from a source? water potential of lignificat…59 / 109
Question 184: Which of the processes involved in water movement through xylem vessels depends on hydrogen bonding between water molecules? A adhesion B c…Question 185: Which statements about water movement in plants are correct? 1 Water can pass through cellulose. 2 Water cannot pass through lignin. 3 Wate…Question 186: Which statements correctly describe transport pathways in dicotyledonous plants? 1 In the apoplast pathway, water does not move through pla…Question 187: Which properties of water molecules are important in the upward flow of water through xylem? 1 Water molecules are attracted to each other …Question 188: What is correct for a phloem sieve tube element that is unloading to a sink? water potential of the lignification of phloem sieve tube the …60 / 109
Question 189: Which statement concerning transpiration is correct? A On a humid day, the water potential gradient between the intercellular air space and…Question 190: The diagram shows a xylem vessel in a root and four adjacent parenchyma cells. As water moves up the xylem vessel, it is replaced by water …Question 191: Which statement correctly describes an event in the process of mass flow in phloem sieve tube elements? A Any part of a plant where sucrose…61 / 109
Question 192: The diagram shows a potato tuber at different stages. 1 dormant tuber (not growing) 2 sprouting roots and shoots 3 growing roots and shoots…Question 193: By which process would water rise up through xylem vessels in a plant root when the shoot has been removed? A capillarity, root pressure an…Question 194: Which changes occur to the water potential and the volume of liquid in the phloem sieve tube element when carbohydrate is moved into a sink…62 / 109
Question 195: The graph shows the diameter of a tree trunk over time. diameter of tree trunk 12:00 00:00 12:00 00:00 12:00 time of day Which statement ex…Question 196: Which terms describe the method by which water is transported within xylem vessel elements? 1 mass flow 2 cohesion-tension 3 osmosis A 1 an…Question 197: Which combination of features is characteristic of a phloem sieve tube element as it is loaded from a source? water potential of the lignif…Question 198: A heating sleeve was placed around the trunk of a small tree at a height of 1m above the ground. This allowed a narrow region of the tree t…63 / 109
Question 199: Which statement correctly describes a transport pathway in plants? A In the apoplast pathway, water may move through plasmodesmata. B In th…Question 200: What is correct for phloem sieve tube elements? A Companion cells provide structural support to the phloem sieve tube elements. B Lignified…Question 201: The statements are descriptions of how water moves across the root to the xylem vessel elements. 1 Water enters cell walls. 2 Water enters …Question 202: Four plants, A, B, C and D, were grown in the same conditions and their transpiration rates measured. Which plant is most likely to be a xe…64 / 109
Question 203: Sucrose moves from a mesophyll cell in a leaf into a phloem sieve tube element. Which changes to the water potential and the volume of liqu…Question 204: The photomicrograph shows a transverse section through part of a plant root. Which tissue inhibits the path of water through the apoplastic…Question 205: Which row correctly describes the adaptations of companion cells, phloem sieve tube elements and xylem vessel elements for their roles? com…65 / 109
Question 206: Irrigating crop plants with water containing low concentrations of salt causes an increase in the concentration of salt in the soil. What e…Question 207: The diagram shows the pathway of water across root cells to the xylem. Which cell is in the endodermis? A B C D xylemQuestion 208: Which row shows the cause of mass flow in the phloem and the direction of movement of phloem sap by mass flow? cause of mass flow direction…66 / 109
Question 209: The photomicrograph shows a vascular bundle. 1 3 2 Which describes the relationship of water potential in the labelled cells? A Cell 3 is l…Question 210: Which features have a role in the transport of water in xylem vessel elements? 1 capillary action 2 cohesion 3 hydrogen bonding A 1, 2 and …Question 211: What is a definition of transpiration? A the evaporation of water vapour from a leaf due to the diffusion of water from an area of low wate…Question 212: What causes water to move from the root hair cells to the endodermis? A diffusion through cell walls, osmosis down a water potential gradie…67 / 109
Question 213: What is true about a Casparian strip? location formed from effect A cell wall of cortical cell lignin closes symplastic pathway B cell wall…Question 214: Which xerophytic adaptations reduce the water potential gradient between leaf surface and atmosphere? 1 rolled leaves 2 hairy leaves 3 sunk…Question 215: When sucrose is loaded into the phloem it has to travel from mesophyll cells to a companion cell and then into the phloem. In many plants, …68 / 109
Question 216: Hydrogen bonding explains many of the properties of water, including the high latent heat of vapourisation and high specific heat capacity.…Question 217: What is correct about the apoplastic pathway and symplastic pathway in a root? apoplastic pathway symplastic pathway A Casparian strip bloc…Question 218: Sucrose moves into a phloem sieve tube element from a leaf mesophyll cell. Which changes to the water potential and the volume of solution …Question 219: A number of processes contribute to maintaining a water potential gradient in plants allowing water to reach the highest parts of a plant. …69 / 109
Question 220: What is a correct statement about the movement of substances absorbed by roots? A Ions have to pass through cell walls to cross the endoder…Question 221: Which arrangement of four molecules of water shows how water may cohere when moving up a xylem vessel? A B key oxygen atom hydrogen atom hy…Question 222: Which statement about sucrose loading into companion cells and then into the phloem sieve tube element is not correct? A Hydrogen ions and …Question 223: External factors change the rate of transpiration, which also affects the water potential gradient of cells in the leaf. Which combination …70 / 109
Question 224: Which changes occur as carbohydrates move out of a root cell into a phloem sieve tube? water potential in a volume of liquid phloem sieve t…Question 225: The circumference of a tree stem was measured continually for 48 hours. The results are shown on the chart recording. circumference of tree…Question 226: Which description of movement in phloem is correct? A Adding sucrose to a sieve tube element increases its water potential so that water en…71 / 109
Question 227: Some fungi cause wilting in crop plants by growing within the xylem vessel elements. Which process will be directly affected by these fungi…Question 228: Which features have a role in the transport of water in xylem vessel elements? 1 capillary action 2 adhesion 3 hydrogen bonding A 1, 2 and …Question 229: The loading of sucrose into companion cells involves a number of processes. Which process is active? A the movement of hydrogen ions into t…Question 230: The statements describe events that occur during the movement of sucrose. 1 Hydrostatic pressure is decreased. 2 Hydrostatic pressure is in…72 / 109
Question 231: The diameter of a tree trunk usually decreases slightly during the day and increases slightly at night. Which three environmental factors, …Question 232: Sucrose moves within a phloem sieve tube from a source to a sink by mass flow. Which type of gradient within the phloem sieve tube between …Question 233: Some of the parts of a plant root involved in water transport are listed. 1 Casparian strip 2 cell walls of cortex cells 3 endodermal cells…Question 234: What is an example of a mass flow system in a plant? A the loading of amino acids from the surrounding tissues into companion cells B the m…73 / 109
Question 235: The diameter of a tree trunk usually decreases slightly during the day. Which changes in environmental factors during the day could cause t…Question 236: Which statement about the role of co-transporter proteins in the movement of sucrose is correct? A Co-transporter proteins pump hydrogen io…Question 237: What contributes to the upward movement of water in a xylem vessel of a plant? 1 cohesion of water molecules by hydrogen bonding 2 adhesion…74 / 109
Question 238: The diameter of a tree trunk usually decreases slightly during the day. Which changes in environmental factors during the day could cause t…Question 239: Different substances, such as sucrose and amino acids, can move in different directions in the phloem sieve tube elements. Which statement …Question 240: Which descriptions of the adaptations of xylem vessel elements to their function are correct? 1 They have pits between vessels allowing wat…75 / 109
Question 241: The diameter of a tree trunk usually decreases slightly during the day. Which changes in environmental factors during the day could cause t…Question 242: A student wanted to find out the rate of transpiration using a potometer as shown. cut shoot reservoir air bubble capillary tube volume bea…76 / 109
Question 243: In plants, assimilates such as sucrose are loaded from source cells into sieve tube elements. The assimilates are then transported from sou…Question 244: Which properties of water molecules are important in the upward flow of water through the xylem? 1 Water molecules are attracted to each ot…Question 245: The graph shows the rate of water absorption and the rate of water loss by a plant during one 24-hour period. The plant was growing in natu…77 / 109
Question 246: Sucrose moves into an actively dividing shoot tip from a phloem sieve tube element. Which changes to the water potential and the volume of …Question 247: Sucrose is loaded into phloem sieve tubes from companion cells. What is the correct order of statements that explains this mechanism? 1 Hyd…Question 248: Water molecules are attracted to each other. This property is important in the upward movement of water in xylem. Which term is used to des…78 / 109
Question 249: The diagram shows a model to demonstrate mass flow. W water concentrated dilute sucrose solution Y X Z sucrose solution partially permeable…Question 250: Which features of companion cells are essential to their function? 1 They are connected to the sieve tube elements by plasmodesmata. 2 They…Question 251: Which statements about water movement in plants are correct? 1 Water can pass through cellulose cell walls. 2 Water cannot pass through lig…79 / 109
Question 252: The diameter of a tree trunk usually decreases slightly during the day. Which changes in environmental factors during the day could cause t…Question 253: Which sequence of events could lead to mass flow in a phloem sieve tube? 1 Sucrose moves into a sieve tube element. 2 Protons (H+) and suc…80 / 109
Question 254: The diagram shows a vascular bundle from the stem of a plant. 3 2 1 Which row describes the functions of the labelled cells? transports tra…Question 255: Which statements explain why transpiration is an inevitable consequence of gas exchange in plants? 1 Hydrolysis reactions are taking place …81 / 109
Question 256: In an investigation, a leafy shoot was attached to a potometer and exposed to a variety of conditions. The time taken for the meniscus to m…Question 257: Proton pumps (H+ pumps) and co-transporters are used by plants when loading sucrose into a phloem sieve tube element at a source. Which row…Question 258: Why does an air bubble in a xylem vessel element stop the flow of water? 1 loss of adhesion 2 loss of cohesion 3 collapse of xylem vessel e…82 / 109
Question 259: Which changes to the water potential and the volume of solution in a phloem sieve tube occur when amino acids are moved into a sink from th…Question 260: Which feature of some xerophytic leaves reduces the rate of transpiration by decreasing the water potential gradient between the internal l…Question 261: Which row is correct for the movement of water in a root? molecule present pathway in Casparian strip A apoplast pathway through intercellu…83 / 109
Question 262: The table contains some information about uptake and movement of water and of mineral ions in plants. water mineral ions mechanism for upta…Question 263: Which changes to the water potential and the volume of solution in the phloem sieve tube occur when sucrose is moved from a photosynthesisi…Question 264: A student wrote the following statements about a possible mechanism for loading sucrose from a source. 1 When energy is released from ATP, …84 / 109
Question 265: The diagrams show transverse sections through parts of plants. 3 1 4 5 6 2 Which row is correct? transports contains lignin organic solutes…Question 266: Which molecules form hydrogen bonds with water during transpiration? 1 cellulose in the xylem wall 2 suberin in the xylem wall 3 other wate…Question 267: Some plant species can take up heavy metal contaminants that are dissolved in soil water and then transport them within the plant. Within p…Question 268: What is the correct route for the movement of water from cell to cell in the apoplast pathway? A through adjacent cell surface membranes B …85 / 109
Question 269: Which row shows the correct sequence for the movement of sucrose into phloem sieve tubes? first second third A diffusion of sucrose into th…Question 270: Which changes to the water potential and the volume of solution in the phloem sieve tube element occur when sucrose is moved from the phloe…Question 271: Which processes occur during the loading of sucrose into phloem sieve tubes? 1 Protons are pumped out of the cytoplasm of the companion cel…86 / 109
Question 272: The electron micrograph shows a cross-section of a leaf vein and some neighbouring cells. Which structure contributes to mass flow by the u…Question 273: Which row is correct for the sucrose concentrations and the water potentials in a source and a sink in a potato plant, at 12:00 p.m.? sucro…Question 274: The diagram shows one possible way in which sucrose may be loaded into a sieve tube element. companion cell 1 protons move out of the compa…87 / 109
Question 275: Sodium chloride is added to a culture solution containing freshwater single-celled plant cells. What happens to the water potential of the …Question 276: Which statements correctly describe transport pathways in dicotyledonous plants? 1 In the apoplast pathway, water may move through plasmode…Question 277: Which statement about the movement of water from roots to leaves is not correct? A A continuous column of water is partly maintained by the…Question 278: Which terms describe the method by which water is transported within xylem vessel elements? 1 cotransport 2 cohesion-tension 3 osmosis A 1 …Question 279: What is the main function of a companion cell in phloem tissue? A providing cytoplasmic contact with the sieve tube element for loading B p…88 / 109
Question 280: The statements describe some of the properties of water. 1 requires a lot of heat energy to evaporate 2 retains a lot of heat energy 3 is a…Question 281: Which xerophytic adaptations reduce the water potential gradient between leaf surface and atmosphere? 1 rolled leaves 2 hairy leaves 3 sunk…Question 282: The diagram shows seven stages of a tulip bulb’s growth. 1 2 3 4 5 6 7 Which row identifies the correct stages in which the tulip bulb is a…89 / 109
Question 283: What would be changed if mitochondrial activity was inhibited by a metabolic poison acting on cells in the phloem tissue? 1 concentration o…Question 284: By which process does sucrose move through phloem sieve tube elements? A active transport B diffusion C facilitated diffusion D mass flowQuestion 285: Which row correctly matches the structure and function of phloem sieve tube elements? structure function A peripheral cytoplasm to provide …Question 286: Which feature of xylem vessel elements helps adhesion during transpiration? A Lignin forms a complete secondary wall. B New vessels carry e…Question 287: Mass flow is the bulk movement of materials from one place to another. How many of the vessels listed carry fluids by mass flow? ● artery ●…90 / 109
Question 288: Cellulose, lignin and suberin are components of various plant cell walls. Descriptions of these cell wall components are listed. 1 a compon…Question 289: The arrows show the direction of water movement across a plant root, from water in the soil to the xylem. plasmodesmata water 1 3 5 7 8 in …Question 290: Which row correctly identifies sources and sinks of sugars? root cells storage cells of absorbing seed that is mineral ions starting to gro…91 / 109
Question 291: What is the correct term to describe intermolecular hydrogen bonding between water molecules? A adhesion B cohesion C osmosis D diffusionQuestion 292: The diagram shows the outline of a xerophytic leaf that had been left for 45 minutes in different conditions, P and Q. Y Y P Q Which statem…Question 293: 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 an…Question 294: How are companion cells involved in loading sucrose into phloem sieve tube elements? A actively through cotransporter proteins and passivel…92 / 109
Question 295: Which statements about the apoplast and symplast pathways are correct? 1 In the apoplast pathway, water molecules move through free spaces …Question 296: Where does water evaporate from during transpiration? A intercellular spaces B leaf surface C mesophyll cell walls D stomatal poresQuestion 297: The diagram shows the outline of three xerophytic leaves of the same type in three different conditions, P, R and S. layer Y layer Y layer …Question 298: Which statement supports the theory of active loading of sucrose into companion cells? A The pH decreases in the cell wall of the companion…93 / 109
Question 299: Which row correctly explains how the structures of phloem sieve tube elements and xylem vessel elements are related to their functions as t…Question 300: 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 end…Question 301: Which statements correctly describe transport pathways in dicotyledonous plants? 1 In the symplast pathway, water may move through intercel…Question 302: Which changes occur as sucrose is transferred from leaves into phloem sieve tubes to be transported to a sink? water potential volume of li…94 / 109
Question 303: The graph shown does not have any axis labels. 0 0 Which row shows appropriate labels for the axes that would explain mass flow in phloem? …95 / 109
Question 304: Four students sketched diagrams of the apoplast pathway and the symplast pathway. Which sketch is the most accurate diagram of the two path…96 / 109
Question 305: The photomicrograph shows some xerophytic adaptations in leaf tissue. 1 2 3 Which row shows the correct functions for structures 1, 2 and 3…Question 306: Which processes are required for the transfer of assimilates from a source cell into a phloem sieve tube? A active transport, facilitated d…97 / 109
Question 307: 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 …Question 308: 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…Question 309: Hydrogen bonding explains many of the properties of water, including the high latent heat of vaporisation and high specific heat capacity. …98 / 109
Question 310: Ammonium ions, NH4 +, can enter the xylem of plant roots by two pathways. ● In the apoplast pathway, ammonium ions move through cell walls …Question 311: Which row correctly shows processes required for the movement of water from a root hair cell to the atmosphere? cohesion diffusion evapora…99 / 109
Question 312: A maize seedling was grown in soil that contained lanthanum ions labelled with a chemical that fluoresces under ultraviolet light. The diag…Question 313: Which description of adhesion and cohesion is correct? A Adhesion refers to the force between the water molecules due to hydrogen bonding. …Question 314: Which conditions are needed to allow the mass flow of sucrose in phloem sieve tubes? phloem sieve tube in sources phloem sieve tube in sink…100 / 109
Question 315: The diagram shows how nicotine is transported from the blood plasma into a cell using a type of cotransporter mechanism. protons move down …Question 316: Which row correctly identifies sinks for sucrose transported by mass flow in plants? root storage growing growing organ leaf bud shoot tip…Question 317: Which statement correctly describes the movement of solutes in the symplast pathway? A Cell surface membranes regulate the selective absorp…101 / 109
Question 318: Which statement helps to explain why water molecules are forced to move through xylem vessel elements as a consequence of transpiration? A …Question 319: Carrier proteins in the cell surface membranes of companion cells are involved in the transfer of assimilates to phloem sieve tubes. The di…Question 320: Which statement correctly identifies the movement of sucrose and amino acids in plant vascular tissue? A They are carried from source to si…102 / 109
Question 321: The diagram shows a longitudinal section of a phloem sieve tube with a companion cell. Where are the mitochondria located for the release o…Question 322: The diagram shows a phloem sieve tube element and a companion cell that are involved in translocation of sucrose. W X Y Z Which process cor…Question 323: Which types of molecules are cotransported into companion cells? A monomers and disaccharides B monomers and polysaccharides C polymers and…103 / 109
Question 324: The diagram shows some structures used for transport in the phloem. cell Y companion cell Z cell direction of phloem sieve tube transport l…Question 325: The diagram shows a section through a root of a dicotyledonous plant. soil particle root hair root cell xylem cell vessel Casparian strip W…104 / 109
Question 326: Which row correctly describes the role of growing leaves as sources or sinks for amino acids and sucrose? amino acids sucrose A leaves act …Question 327: Which changes occur as amino acids are moved into phloem sieve tubes at a source? change in change in water potential in volume of sap in p…Question 328: Which row is correct for transpiration? definition of transpiration comparison of water potential A evaporation of water higher inside air …105 / 109
Question 329: The diagram shows some root cells. cell wall vacuole cytoplasm key pathway of water moving from the soil Which statement is correct for the…Question 330: The graph shows the diameter of a tree trunk at different times. J L diameter of tree trunk K / arbitrary units 00:00 12:00 00:00 time of d…106 / 109
Question 331: The plan diagrams of transverse sections of two plant organs are shown. These are not drawn to scale. S Q T R Which tissues contain proton …Question 332: The diagram shows a bond between two molecules transported in a xylem vessel. δ– O bond R δ+ δ+ H H δ– O δ+ δ+ H H Which row correctly name…Question 333: How can water and solutes move through a leaf? A through the lignified endodermis using the apoplast pathway B through the cytoplasm of cel…107 / 109
Question 334: Two plants, K and L, are parasites of other plants. Both species grow structures that invade the vascular tissue of plants. Plant K grows i…Question 335: 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…Question 336: 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 tub…Question 337: What causes water to move from the root hair cells to the endodermis? A diffusion through cell walls and osmosis down a water potential gra…108 / 109
Question 338: Which changes occur as carbohydrate is moved into a sink? water potential volume of liquid of the sieve tube of the sieve element becomes t…Question 339: Which statement about the pathway taken by a water molecule travelling from the soil to the xylem is correct? A A water molecule in a corte…Question 340: Amino acids move from a phloem sieve tube element into a root cell. What are the changes to the water potential and the volume of liquid in…109 / 109

Mark scheme340 answers

Answers below. Sit the paper first if you are practising.

Pastlit

Biology 9700 · Transport mechanisms — Paper 1

A Level · topical answer key — answer key (teacher use)

Question

Answer

Marks

1B1
2A1
3D1
4B1
5C1
6D1
7B1
8A1
9B1
10B1
11A1
12A1
13D1
14C1
15B1
16B1
17A1
18B1
19A1
20B1
21A1
22A1
23B1
24A1
25D1
26A1
27D1
28A1
29C1
30A1
31D1
32A1
33B1
34C1
35D1
36A1
37C1
38D1
39B1
40B1
41B1
42D1
43B1
44C1
45B1
46B1
47D1
48A1
49B1
1 / 7

Pastlit

Biology 9700 · Transport mechanisms — Paper 1

A Level · topical answer key — answer key (teacher use)

Question

Answer

Marks

50A1
51D1
52C1
53C1
54D1
55B1
56A1
57B1
58C1
59B1
60A1
61B1
62D1
63D1
64D1
65A1
66A1
67A1
68B1
69A1
70B1
71B1
72D1
73C1
74D1
75D1
76B1
77A1
78D1
79C1
80D1
81D1
82D1
83B1
84D1
85B1
86D1
87A1
88A1
89C1
90B1
91B1
92D1
93B1
94B1
95D1
96C1
97A1
98A1
2 / 7

Pastlit

Biology 9700 · Transport mechanisms — Paper 1

A Level · topical answer key — answer key (teacher use)

Question

Answer

Marks

99D1
100B1
101A1
102B1
103B1
104A1
105B1
106D1
107B1
108A1
109A1
110D1
111D1
112A1
113D1
114D1
115C1
116D1
117A1
118C1
119D1
120D1
121A1
122D1
123C1
124A1
125B1
126A1
127A1
128A1
129A1
130B1
131B1
132C1
133C1
134D1
135A1
136C1
137A1
138B1
139C1
140—1
141—1
142—1
143—1
144—1
145D1
146B1
147D1
3 / 7

Pastlit

Biology 9700 · Transport mechanisms — Paper 1

A Level · topical answer key — answer key (teacher use)

Question

Answer

Marks

148D1
149D1
150D1
151B1
152A1
153D1
154B1
155A1
156A1
157A1
158C1
159A1
160D1
161A1
162C1
163C1
164D1
165B1
166D1
167A1
168B1
169A1
170C1
171B1
172D1
173A1
174A1
175D1
176D1
177C1
178A1
179D1
180C1
181C1
182D1
183C1
184B1
185B1
186A1
187A1
188A1
189B1
190A1
191D1
192B1
193B1
194C1
195A1
196A1
4 / 7

Pastlit

Biology 9700 · Transport mechanisms — Paper 1

A Level · topical answer key — answer key (teacher use)

Question

Answer

Marks

197C1
198C1
199C1
200D1
201C1
202D1
203D1
204B1
205C1
206C1
207C1
208B1
209A1
210A1
211B1
212A1
213B1
214B1
215B1
216B1
217B1
218D1
219A1
220D1
221B1
222C1
223C1
224D1
225B1
226D1
227A1
228A1
229B1
230A1
231D1
232B1
233A1
234B1
235A1
236B1
237A1
238D1
239D1
240A1
241B1
242C1
243C1
244A1
245A1
5 / 7

Pastlit

Biology 9700 · Transport mechanisms — Paper 1

A Level · topical answer key — answer key (teacher use)

Question

Answer

Marks

246A1
247C1
248B1
249B1
250B1
251B1
252B1
253D1
254B1
255D1
256A1
257C1
258D1
259A1
260C1
261A1
262A1
263D1
264D1
265B1
266C1
267A1
268B1
269D1
270A1
271B1
272C1
273B1
274C1
275C1
276D1
277D1
278C1
279A1
280D1
281B1
282C1
283A1
284D1
285A1
286D1
287D1
288D1
289C1
290A1
291B1
292A1
293A1
294A1
6 / 7

Pastlit

Biology 9700 · Transport mechanisms — Paper 1

A Level · topical answer key — answer key (teacher use)

Question

Answer

Marks

295B1
296C1
297A1
298A1
299C1
300B1
301D1
302D1
303C1
304D1
305B1
306A1
307B1
308B1
309B1
310D1
311A1
312B1
313D1
314B1
315B1
316A1
317A1
318B1
319A1
320A1
321B1
322B1
323A1
324B1
325A1
326D1
327B1
328D1
329A1
330C1
331C1
332B1
333B1
334B1
335B1
336A1
337A1
338C1
339D1
340A1
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Another paper, or another topic

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All of Transport in plants →

Questions as text

Q1 · A region of a stem of a plant is heated to kill the cells in the living vascular tissues 9700/11 Oct/Nov 2004

29 A region of a stem of a plant is heated to kill the cells in the living vascular tissues. How will this treatment affect the transport between roots and leaves via xylem and phloem? xylem phloem v v J transport continues x transport stops 0 0O WD > v x x v x x

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2004

Q2 · Some soil-borne fungi cause wilting in crop plants by growing within the xylem vessels 9700/11 Oct/Nov 2004

30 Some soil-borne fungi cause wilting in crop plants by growing within the xylem vessels. Which process will be directly affected by these fungi? A conduction in the apoplast B development of root pressure C stomatal movement D uptake of water by root hairs

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2004

Q3 · The movement of water through the vascular tissue in plants relies on which property of… 9700/11 May/June 2006

12 The movement of water through the vascular tissue in plants relies on which property of water? A changes in density with temperature B good solvent for ions and polar molecules C high specific heat capacity D strong cohesive forces between molecules

1 marks

Answer: D

This question in 9700/11 May/June 2006

Q4 · The graph shows the relationship between the loss of water vapour through stomata and an… 9700/11 May/June 2006

25 The graph shows the relationship between the loss of water vapour through stomata and an environmental factor. loss of water vapour environmental factor What is the environmental factor? A air temperature B atmospheric humidity C light intensity D wind velocity

1 marks

Answer: B

This question in 9700/11 May/June 2006

Q5 · What is responsible for the movement of water up xylem vessels in plants? 9700/11 May/June 2006

27 What is responsible for the movement of water up xylem vessels in plants? A active loading of water against the water potential gradient in the roots and osmosis in the vessels B increasing water potential at the top of xylem vessels, and osmosis in the roots C decreasing water potential at the top of the xylem vessels, with cohesion of water in the vessels D translocation in the leaves, with capillarity in the xylem vessels

1 marks

Answer: C

This question in 9700/11 May/June 2006

Q6 · A water potential gradient causes water to move through xylem 9700/11 Oct/Nov 2006

25 A water potential gradient causes water to move through xylem. Which process is mainly responsible for this water potential gradient? A capillarity B osmosis C translocation D transpiration

1 marks

Answer: D

This question in 9700/11 Oct/Nov 2006

Q7 · During transpiration, what is the site of evaporation of water in the leaves? 9700/11 Oct/Nov 2006

26 During transpiration, what is the site of evaporation of water in the leaves? A air spaces B mesophyll cell walls C stomata D walls of xylem vessels

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2006

Q8 · The diagram represents the phloem pathway, with adjacent cells, from leaf to root in a… 9700/11 Oct/Nov 2007

24 The diagram represents the phloem pathway, with adjacent cells, from leaf to root in a plant. 2 leaf cell 1 chloroplast parenchyma cell nucleus companion cell root cell Which process is occurring between 1 to 2 and what is the effect on the water potential at 2? process from 1 to 2 water potential at 2 A active transport of sucrose becomes more negative B active transport of sucrose becomes less negative C diffusion of sucrose becomes more negative D diffusion of sucrose becomes less negative

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2007

Q9 · The diagram represents a transverse section through a part of the root of a plant 9700/11 Oct/Nov 2007

25 The diagram represents a transverse section through a part of the root of a plant. cortex xylem soil water Which values of water potential (kPa) in the xylem and soil water help to explain why water passes from the soil into the xylem across the cortex? xylem soil water A –700 kPa 0 kPa B –1800 kPa –700 kPa C 0 kPa –1800 kPa D –700 kPa –1800 kPa

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2007

Q10 · Translocation in plants moves sucrose from sources to sinks 9700/11 Oct/Nov 2007

26 Translocation in plants moves sucrose from sources to sinks. Which of the following can be a source and which a sink? source sink A germinating seeds green leaves B green leaves storage roots C phloem germinating seeds D storage roots phloem

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2007

Q11 · A large number of aphids were used to collect samples of the contents of the sieve tubes… 9700/11 May/June 2008

25 A large number of aphids were used to collect samples of the contents of the sieve tubes of a tomato plant. sieve tube element sample taken micopipette tomato plant stem (aphid and stem are not drawn to the same scale) Different samples of the sieve tube solution were tested. Which was the correct result? Benedict’s test iodine in KI before hydrolysis after hydrolysis A blue red brown B blue blue blue / black C red blue blue / black D red red brown

1 marks

Answer: A

This question in 9700/11 May/June 2008

Q12 · The diagram shows a dendrograph fixed to a tree 9700/11 May/June 2008

26 The diagram shows a dendrograph fixed to a tree. The dendrograph records changes in the diameter of the tree. Some results are shown on the chart recording. dendrograph fixed to a tree chart recording tree chart diameter noon 12pm noon 12pm noon time of day What explains the diameter changes recorded during the day and night? A cohesive tension forces increased during the day B mass flow of sucrose increased during the night C root pressure decreased during the day D thermal expansion and contraction of water in the tree

1 marks

Answer: A

This question in 9700/11 May/June 2008

Q13 · Which features of xerophytes reduce water loss by transpiration? 9700/11 May/June 2008

30 Which features of xerophytes reduce water loss by transpiration? rolled leaves | swollen leaves | sunken stomata | thick waxy cuticle 0 OO DW > << x SA 4 Ko 4 Ko 4

1 marks

Answer: D

This question in 9700/11 May/June 2008

Q14 · Four solutions, with different water potentials are listed 9700/11 Oct/Nov 2008

23 Four solutions, with different water potentials are listed. 1 endodermal cell solution 2 root hair cell solution 3 soil water solution 4 solution in a xylem vessel Which list has the solutions in order from the highest (least negative) water potential to the lowest (most negative) water potential? highest lowest A 1 2 3 4 B 2 4 1 3 C 3 2 1 4 D 4 1 3 2

1 marks

Answer: C

This question in 9700/11 Oct/Nov 2008

Q15 · Which feature of a root hair cell is not an adaptation for water uptake from the soil… 9700/11 Oct/Nov 2008

24 Which feature of a root hair cell is not an adaptation for water uptake from the soil solution? A lack of a waxy cuticle B large numbers of mitochondria C long, thin extension to the cell D thin cellulose cell wall

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2008

Q16 · The diagram shows a model to demonstrate the mass-flow hypothesis of translocation 9700/11 Oct/Nov 2008

25 The diagram shows a model to demonstrate the mass-flow hypothesis of translocation. W water concentrated dilute sucrose solution Y X Z sucrose solution partially permeable partially permeable membrane membrane In a plant, what are the structures W, X, Y and Z and what is the direction of flow of solution along W? phloem xylem roots leaves direction of flow along W A W X Y Z From Z to Y B W X Z Y From Y to Z C X W Y Z From Y to Z D X W Z Y From Z to Y

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2008

Q17 · What is the sequence of events in the translocation of assimilates? 9700/12 Oct/Nov 2009

25 What is the sequence of events in the translocation of assimilates? A active loading of sucrose into sieve elements via companion cells at the source, increased hydrostatic pressure, mass flow, unloading at the sink B hydrolysis of storage compounds in sinks, lowered water potential in sink, unloading of sucrose from sieve elements down the water potential gradient, mass flow from the source C lowered pressure in sieve elements at the source, movement of sucrose down the pressure gradient from companion cells, mass flow down a diffusion gradient to the sink D mass flow of dissolved sucrose via companion cells into the sieve element at the source, lowered hydrostatic pressure, diffusion of sucrose down concentration gradient to sink, active unloading

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2009

Q18 · What occurs in the sieve tube elements of a photosynthesising leaf and an actively… 9700/11 May/June 2010

26 What occurs in the sieve tube elements of a photosynthesising leaf and an actively growing root? sieve tube elements in leaf sieve tube elements in root A water potential decreases sugars are moved in B water potential decreases sugars are moved out C water potential increases sugars are moved in D water potential increases sugars are moved out

1 marks

Answer: B

This question in 9700/11 May/June 2010

Q19 · Some soil-borne fungi cause wilting in crop plants by growing within the xylem vessels 9700/11 May/June 2010

27 Some soil-borne fungi cause wilting in crop plants by growing within the xylem vessels. Which process will be directly affected by these fungi? A cohesion between water molecules B development of root pressure C mass flow during translocation D uptake of water by root hair cells

1 marks

Answer: A

This question in 9700/11 May/June 2010

Q20 · What occurs in the sieve tube elements of a photosynthesising leaf and an actively… 9700/12 May/June 2010

7 What occurs in the sieve tube elements of a photosynthesising leaf and an actively growing root? sieve tube elements in leaf sieve tube elements in root A water potential decreases sugars are moved in B water potential decreases sugars are moved out C water potential increases sugars are moved in D water potential increases sugars are moved out

1 marks

Answer: B

This question in 9700/12 May/June 2010

Q21 · Some soil-borne fungi cause wilting in crop plants by growing within the xylem vessels 9700/12 May/June 2010

8 Some soil-borne fungi cause wilting in crop plants by growing within the xylem vessels. Which process will be directly affected by these fungi? A cohesion between water molecules B development of root pressure C mass flow during translocation D uptake of water by root hair cells

1 marks

Answer: A

This question in 9700/12 May/June 2010

Q22 · Some soil-borne fungi cause wilting in crop plants by growing within the xylem vessels 9700/13 May/June 2010

8 Some soil-borne fungi cause wilting in crop plants by growing within the xylem vessels. Which process will be directly affected by these fungi? A cohesion between water molecules B development of root pressure C mass flow during translocation D uptake of water by root hair cells

1 marks

Answer: A

This question in 9700/13 May/June 2010

Q23 · What occurs in the sieve tube elements of a photosynthesising leaf and an actively… 9700/13 May/June 2010

9 What occurs in the sieve tube elements of a photosynthesising leaf and an actively growing root? sieve tube elements in leaf sieve tube elements in root A water potential decreases sugars are moved in B water potential decreases sugars are moved out C water potential increases sugars are moved in D water potential increases sugars are moved out

1 marks

Answer: B

This question in 9700/13 May/June 2010

Q24 · The diagram shows some adjacent cells from the root of a plant 9700/11 Oct/Nov 2010

26 The diagram shows some adjacent cells from the root of a plant. Which is the apoplastic pathway of water movement? A B C D

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2010

Q25 · What determines the rate of water movement from the roots to the leaves? 9700/11 Oct/Nov 2010

27 What determines the rate of water movement from the roots to the leaves? A absorption of water through the root hair cells B development of a less negative water potential in the leaves C diffusion of water through the stomata D evaporation of water from the mesophyll cell walls

1 marks

Answer: D

This question in 9700/11 Oct/Nov 2010

Q26 · Which processes are involved in transpiration? 9700/12 Oct/Nov 2010

23 Which processes are involved in transpiration? 1 the diffusion of water vapour from stomata 2 the mass flow of water through the xylem 3 the evaporation of water from spongy mesophyll cells 4 the evaporation of water vapour from exposed leaves A 1, 2, 3 and 4 B 1 and 3 only C 1 and 4 only D 2, 3 and 4 only

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2010

Q27 · Water passes across leaf tissues by different routes as a result of • differences in… 9700/12 Oct/Nov 2010

25 Water passes across leaf tissues by different routes as a result of • differences in water potential • the pull transmitted by cohesive forces between water molecules. The diagram shows three routes by which water can travel. epidermal cuticle cell palisade cell xylem vessel cells of the key spongy route 1 = apoplastic mesophyll route 2 = vacuolar route 3 = symplastic cuticle atmosphere epidermal cell Which row correctly identifies why water passes across leaf tissues by the different routes? differences in pull transmitted by water potential cohesive forces A route 1 routes 2 and 3 B routes 1 and 3 route 2 C route 2 routes 1 and 3 D routes 2 and 3 route 1

1 marks

Answer: D

This question in 9700/12 Oct/Nov 2010

Q28 · The diagram shows the water potential (Ψ) in some plant cells and in their environment 9700/12 Oct/Nov 2010

27 The diagram shows the water potential (Ψ) in some plant cells and in their environment. cell 1 cell 2 Ψ = Ψ = cell 3 – 5 kPa Ψ = – 7 kPa – 4 kPa environment Ψ = – 5 kPa Which statements are correct for this situation? 1 Water moves into and out of all three cells. 2 There is a net movement of water into cell 1. 3 There is no movement of water from the environment to cell 2. 4 Water moves out of cell 3 so it becomes plasmolysed. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2010

Q29 · During transpiration, what is the site of evaporation of water in the leaves? 9700/11 May/June 2011

26 During transpiration, what is the site of evaporation of water in the leaves? A air spaces B guard cell walls C mesophyll cell walls D stomata

1 marks

Answer: C

This question in 9700/11 May/June 2011

Q30 · The photomicrograph shows a vascular bundle 9700/11 May/June 2011

27 The photomicrograph shows a vascular bundle. 1 3 2 Which describes the relationship of water potential in the labelled cells? A cell 3 less negative than cell 1 B cell 2 less negative than cell 3 C cell 3 more negative than cells 1 and 2 D cells 1, 2 and 3 have the same water potential

1 marks

Answer: A

This question in 9700/11 May/June 2011

Q31 · The diagram represents the movement of water through a plant 9700/11 May/June 2011

28 The diagram represents the movement of water through a plant. 3 water vapour is lost from leaves 2 water passes 2 water passes 2 water passes up the stem up the stem up the stem 1 water enters the root Which row identifies the processes involved during the stages of water movement shown? cohesion and transpiration osmosis adhesion A 1 2 3 B 1 3 2 C 2 1 3 D 2 3 1

1 marks

Answer: D

This question in 9700/11 May/June 2011

Q32 · Which processes are involved in transport in both phloem and xylem? 9700/12 May/June 2011

28 Which processes are involved in transport in both phloem and xylem? 1 diffusion 2 mass flow 3 osmosis A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/12 May/June 2011

Q33 · The graph shows the results of measuring the concentration of sucrose in the xylem… 9700/12 May/June 2011

30 The graph shows the results of measuring the concentration of sucrose in the xylem, phloem and leaves of a plant during 24 hours. phloem sucrose concentration leaves xylem 06 00 12 00 18 00 00 00 time of day Which conclusion can be drawn from these results? A Osmosis moves water from the xylem to the phloem. B Sucrose is actively transported into the phloem from the leaves. C Sucrose is moved in both directions in the phloem. D Xylem tissue uses sucrose as a source of energy.

1 marks

Answer: B

This question in 9700/12 May/June 2011

Q34 · Water that is present inside a root hair cell may leave the cell and pass to the xylem 9700/12 May/June 2011

31 Water that is present inside a root hair cell may leave the cell and pass to the xylem. Through which pathway must the water travel? A apoplast B plasmodesmata C symplast D vacuoles

1 marks

Answer: C

This question in 9700/12 May/June 2011

Q35 · The diagram represents the movement of water through a plant 9700/13 May/June 2011

1 The diagram represents the movement of water through a plant. 3 water vapour is lost from leaves 2 water passes 2 water passes 2 water passes up the stem up the stem up the stem 1 water enters the root Which row identifies the processes involved during the stages of water movement shown? cohesion and transpiration osmosis adhesion A 1 2 3 B 1 3 2 C 2 1 3 D 2 3 1

1 marks

Answer: D

This question in 9700/13 May/June 2011

Q36 · The photomicrograph shows a vascular bundle 9700/13 May/June 2011

3 The photomicrograph shows a vascular bundle. 1 3 2 Which describes the relationship of water potential in the labelled cells? A cell 3 less negative than cell 1 B cell 2 less negative than cell 3 C cell 3 more negative than cells 1 and 2 D cells 1, 2 and 3 have the same water potential

1 marks

Answer: A

This question in 9700/13 May/June 2011

Q37 · During transpiration, what is the site of evaporation of water in the leaves? 9700/13 May/June 2011

21 During transpiration, what is the site of evaporation of water in the leaves? A air spaces B guard cell walls C mesophyll cell walls D stomata

1 marks

Answer: C

This question in 9700/13 May/June 2011

Q38 · In which combination of environmental conditions are the stomata of a plant most likely… 9700/11 Oct/Nov 2011

28 In which combination of environmental conditions are the stomata of a plant most likely to close? atmospheric soil water wind humidity potential speed A high low high B high low low C low high high D low low high

1 marks

Answer: D

This question in 9700/11 Oct/Nov 2011

Q39 · The diagram shows the tissues involved in the transport of sucrose in a plant 9700/11 Oct/Nov 2011

29 The diagram shows the tissues involved in the transport of sucrose in a plant. Where is the highest concentration of sucrose? phloem sieve tube companion element cell B mesophyll cell A root cell C D

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2011

Q40 · Which evidence supports the cohesion-tension theory for the movement of water in… 9700/11 Oct/Nov 2011

30 Which evidence supports the cohesion-tension theory for the movement of water in flowering plants? 1 When the rate of transpiration of a tree is maximum, the diameter of the trunk is minimum. 2 When a plant shoot is removed close to the base of the stem, sap leaks out from the cut. 3 Evaporation of water from a porous pot can exert a force that draws water up a glass tube attached underneath the pot. 4 Droplets of water form at the edge of leaves of plants growing in conditions of soil with high water content and air with high humidity. A 1 and 2 B 1 and 3 C 2 and 3 D 2 and 4

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2011

Q41 · Which evidence supports the cohesion-tension theory for the movement of water in… 9700/13 Oct/Nov 2011

38 Which evidence supports the cohesion-tension theory for the movement of water in flowering plants? 1 When the rate of transpiration of a tree is maximum, the diameter of the trunk is minimum. 2 When a plant shoot is removed close to the base of the stem, sap leaks out from the cut. 3 Evaporation of water from a porous pot can exert a force that draws water up a glass tube attached underneath the pot. 4 Droplets of water form at the edge of leaves of plants growing in conditions of soil with high water content and air with high humidity. A 1 and 2 B 1 and 3 C 2 and 3 D 2 and 4

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2011

Q42 · In which combination of environmental conditions are the stomata of a plant most likely… 9700/13 Oct/Nov 2011

39 In which combination of environmental conditions are the stomata of a plant most likely to close? atmospheric soil water wind humidity potential speed A high low high B high low low C low high high D low low high

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2011

Q43 · The diagram shows the tissues involved in the transport of sucrose in a plant 9700/13 Oct/Nov 2011

40 The diagram shows the tissues involved in the transport of sucrose in a plant. Where is the highest concentration of sucrose? phloem sieve tube companion element cell B mesophyll cell A root cell C D

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2011

Q44 · During transpiration, from where does the evaporation of water occur? 9700/11 May/June 2012

23 During transpiration, from where does the evaporation of water occur? A intercellular spaces B leaf surface C mesophyll cell walls D stomatal pores

1 marks

Answer: C

This question in 9700/11 May/June 2012

Q45 · The diagram shows a model to demonstrate the mass flow hypothesis of translocation 9700/11 May/June 2012

24 The diagram shows a model to demonstrate the mass flow hypothesis of translocation. W water concentrated dilute sucrose solution Y X Z sucrose solution partially permeable partially permeable membrane membrane In a plant, what are the structures W, X, Y and Z and what is the direction of flow of solution along W? phloem xylem roots leaves direction of flow along W A W X Y Z from Z to Y B W X Z Y from Y to Z C X W Y Z from Y to Z D X W Z Y from Z to Y

1 marks

Answer: B

This question in 9700/11 May/June 2012

Q46 · The graph shows stomatal opening and closing in the leaves of a species of Pelargonium… 9700/11 May/June 2012

25 The graph shows stomatal opening and closing in the leaves of a species of Pelargonium, during a 24 hour period. 100 light dark light 80 percentage of 60 stomata that are open 40 20 0 15 00 18 00 21 00 00 00 03 00 06 00 09 00 12 00 15 00 time of day What can be concluded? A Gas exchange occurs when stomata are open. B Stomata open as light intensity increases. C Stomata open as temperature increases. D Transpiration does not occur in the dark.

1 marks

Answer: B

This question in 9700/11 May/June 2012

Q47 · When transpiration is at a maximum rate, tree trunks decrease in diameter 9700/11 May/June 2012

26 When transpiration is at a maximum rate, tree trunks decrease in diameter. Which statement explains this? A There is decreased suction pressure in the leaves. B There is less adhesion between water and xylem vessel walls. C There is less water in the xylem vessels. D The water in the xylem vessels is under increased tension.

1 marks

Answer: D

This question in 9700/11 May/June 2012

Q48 · Which statement explains how mass flow arises in sieve tube elements? 9700/11 May/June 2012

27 Which statement explains how mass flow arises in sieve tube elements? A Sucrose actively loaded into sieve tube elements decreases the water potential causing the hydrostatic pressure to increase. B Sucrose actively loaded into sieve tube elements increases the water potential causing the hydrostatic pressure to decrease. C Sucrose diffused into sieve tube elements decreases the water potential causing the hydrostatic pressure to increase. D Sucrose diffused into sieve tube elements increases the water potential causing the hydrostatic pressure to decrease.

1 marks

Answer: A

This question in 9700/11 May/June 2012

Q49 · Which row identifies the tissue that contains the Casparian strip and the molecule… 9700/12 May/June 2012

23 Which row identifies the tissue that contains the Casparian strip and the molecule forming this strip? tissue molecule A cortex lignin B endodermis suberin C epidermis cellulose D xylem lignin

1 marks

Answer: B

This question in 9700/12 May/June 2012

Q50 · Which of the following are included in the apoplast pathway? 9700/12 May/June 2012

24 Which of the following are included in the apoplast pathway? 1 living components 2 plant vacuoles 3 cell walls 4 xylem vessels A 3 only B 1 and 2 only C 3 and 4 only D 1, 2 and 4 only

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Answer: A

This question in 9700/12 May/June 2012

Q51 · Which statement explains why the circumference (girth) of a tree is less in the middle of… 9700/12 May/June 2012

25 Which statement explains why the circumference (girth) of a tree is less in the middle of the day than at night? A Mineral uptake by the root hair cells decreases during the night because root pressure has decreased. B Stomata close during the night and there is a build-up of water in the vascular tissue within the stem. C The phloem sieve tubes fill with dissolved solutes because the translocation rate is reduced at night. D There is less tension in the xylem vessels at night because the rate of transpiration is at a minimum.

1 marks

Answer: D

This question in 9700/12 May/June 2012

Q52 · Sucrose is transported in solution in the phloem of plants 9700/12 May/June 2012

26 Sucrose is transported in solution in the phloem of plants. Transport takes place from sources to sinks. The process depends on differences in hydrostatic pressure between the sources and the sinks. X leaf tissue parenchyma cell nucleus chloroplast companion cell Y root tissue Which tissues are either a source or a sink and what is the hydrostatic pressure at X and Y within the phloem? tissue hydrostatic pressure leaf root high low A sink source X Y B sink source Y X C source sink X Y D source sink Y X

1 marks

Answer: C

This question in 9700/12 May/June 2012

Q53 · During transpiration, from where does the evaporation of water occur? 9700/13 May/June 2012

26 During transpiration, from where does the evaporation of water occur? A intercellular spaces B leaf surface C mesophyll cell walls D stomatal pores

1 marks

Answer: C

This question in 9700/13 May/June 2012

Q54 · When transpiration is at a maximum rate, tree trunks decrease in diameter 9700/13 May/June 2012

27 When transpiration is at a maximum rate, tree trunks decrease in diameter. Which statement explains this? A There is decreased suction pressure in the leaves. B There is less adhesion between water and xylem vessel walls. C There is less water in the xylem vessels. D The water in the xylem vessels is under increased tension.

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Answer: D

This question in 9700/13 May/June 2012

Q55 · The graph shows stomatal opening and closing in the leaves of a species of Pelargonium… 9700/13 May/June 2012

28 The graph shows stomatal opening and closing in the leaves of a species of Pelargonium, during a 24 hour period. 100 light dark light 80 percentage of 60 stomata that are open 40 20 0 15 00 18 00 21 00 00 00 03 00 06 00 09 00 12 00 15 00 time of day What can be concluded? A Gas exchange occurs when stomata are open. B Stomata open as light intensity increases. C Stomata open as temperature increases. D Transpiration does not occur in the dark.

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Answer: B

This question in 9700/13 May/June 2012

Q56 · Which statement explains how mass flow arises in sieve tube elements? 9700/13 May/June 2012

29 Which statement explains how mass flow arises in sieve tube elements? A Sucrose actively loaded into sieve tube elements decreases the water potential causing the hydrostatic pressure to increase. B Sucrose actively loaded into sieve tube elements increases the water potential causing the hydrostatic pressure to decrease. C Sucrose diffused into sieve tube elements decreases the water potential causing the hydrostatic pressure to increase. D Sucrose diffused into sieve tube elements increases the water potential causing the hydrostatic pressure to decrease.

1 marks

Answer: A

This question in 9700/13 May/June 2012

Q57 · The diagram shows a model to demonstrate the mass flow hypothesis of translocation 9700/13 May/June 2012

30 The diagram shows a model to demonstrate the mass flow hypothesis of translocation. W water concentrated dilute sucrose solution Y X Z sucrose solution partially permeable partially permeable membrane membrane In a plant, what are the structures W, X, Y and Z and what is the direction of flow of solution along W? phloem xylem roots leaves direction of flow along W A W X Y Z from Z to Y B W X Z Y from Y to Z C X W Y Z from Y to Z D X W Z Y from Z to Y

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Answer: B

This question in 9700/13 May/June 2012

Q58 · The diagram shows a model which can be used to demonstrate mass flow 9700/11 Oct/Nov 2012

24 The diagram shows a model which can be used to demonstrate mass flow. tube T concentrated X Y dilute sucrose sucrose solution solution water rigid partially permeable containers X and Y are filled with sucrose solutions of different concentrations, causing water to move in or out of X and Y by osmosis or as a result of hydrostatic pressure. Sucrose solution then moves through tube T joining X and Y. Which description is correct? water potential in X direction of movement of compared with Y sucrose solution in tube T A less negative from X to Y B less negative from Y to X C more negative from X to Y D more negative from Y to X

1 marks

Answer: C

This question in 9700/11 Oct/Nov 2012

Q59 · Which of the following statements explain why a stem is both cut and connected to a… 9700/11 Oct/Nov 2012

25 Which of the following statements explain why a stem is both cut and connected to a potometer under water? 1 To prevent plasmolysis of xylem vessel elements 2 To prevent the collapse of xylem vessel elements 3 To prevent air entering xylem vessel elements A 1 only B 3 only C 2 and 3 only D 1, 2 and 3

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2012

Q60 · What is correct about the uptake and transport of water in plants? 9700/12 Oct/Nov 2012

24 What is correct about the uptake and transport of water in plants? 1 water transported by the symplast pathway enters root hair cells down a water potential gradient 2 water is transported in xylem by the symplast and apoplast pathways to reach the leaves 3 water transported by the apoplast pathway through plasmodesmata must pass through cell surface membranes of endodermal cells A 1 only B 3 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2012

Q61 · Which combination of conditions increases the rate of transpiration in plants? 9700/12 Oct/Nov 2012

25 Which combination of conditions increases the rate of transpiration in plants? light intensity humidity temperature A high high low B high low high C low high low D low low high

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2012

Q62 · Which statement explains why sucrose, rather than glucose, is transported by phloem? 9700/12 Oct/Nov 2012

26 Which statement explains why sucrose, rather than glucose, is transported by phloem? A Sucrose can pass through plant cell surface membranes more easily. B Sucrose is a disaccharide and is more easily converted to starch. C Sucrose is a larger molecule. D Sucrose is a non-reducing sugar, so is less reactive.

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Answer: D

This question in 9700/12 Oct/Nov 2012

Q63 · Which correctly matches the structure and function of sieve tube elements? 9700/13 Oct/Nov 2012

22 Which correctly matches the structure and function of sieve tube elements? structure function A cellulose cell wall with no lignin to prevent loss of water B end walls modified to slow down the rate of form sieve plates transport of solutes C elongated cells joined form a tube to transport dissolved end to end mineral ions and water D peripheral cytoplasm to provide as little resistance with no nucleus to flow as possible

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2012

Q64 · How do single-celled organisms survive without a specialised transport system? 9700/13 Oct/Nov 2012

23 How do single-celled organisms survive without a specialised transport system? A Their cell surface membranes are totally permeable. B They do not move very often. C They do not need to absorb oxygen. D They have a large surface area to volume ratio.

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2012

Q65 · The photomicrograph shows a transverse section of a leaf 9700/13 Oct/Nov 2012

24 The photomicrograph shows a transverse section of a leaf. Which cell has the least negative water potential? C B D A

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2012

Q66 · What occurs during the movement of water through the apoplast pathway? 9700/13 Oct/Nov 2012

25 What occurs during the movement of water through the apoplast pathway? 1 water enters cell wall 2 water enters cytoplasm through plasma membrane 3 water enters vacuoles 4 water moves from cell to cell through plasmodesmata 5 water moves from cell wall to cell wall through intercellular spaces A 1 and 5 B 2 and 4 C 1, 3 and 4 D 2, 3 and 5

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2012

Q67 · The loading of sucrose into companion cells involves a number of processes listed below 9700/11 May/June 2013

26 The loading of sucrose into companion cells involves a number of processes listed below. Which is an active process? A the movement of H+ ions from companion cells B the movement of H+ ions into companion cells C the movement of sucrose from companion cells D the movement of sucrose into companion cells

1 marks

Answer: A

This question in 9700/11 May/June 2013

Q68 · Which statement concerning transpiration is correct? 9700/11 May/June 2013

27 Which statement concerning transpiration is correct? A On a humid day, the water potential gradient between the intercellular air space and the external atmosphere increases to stimulate water loss by evaporation. B Water arriving at the spongy mesophyll cells via the symplast pathway must move by osmosis through the cell surface membrane before evaporation from the surface of the cells. C Water diffuses down the water potential gradient from the saturated air space through the guard cells before evaporating from the surface of the cells into the atmosphere. D Water moves up the xylem in the apoplast pathway and can continue on this pathway by osmosis to reach the spongy mesophyll cells before evaporating into the intercellular air space.

1 marks

Answer: B

This question in 9700/11 May/June 2013

Q69 · The diagram shows three xerophytic leaves of the same type in three different conditions… 9700/12 May/June 2013

26 The diagram shows three xerophytic leaves of the same type in three different conditions, P, R and S. layer X X X P R S Which description of the water potential of the cells in layer X is correct? water potential of cells in layer X P R S A less negative than R and S more negative than P and S more negative than P B less negative than S more negative than P less negative than P C more negative than R less negative than S less negative than R D more negative than R and S less negative than P more negative than P

1 marks

Answer: A

This question in 9700/12 May/June 2013

Q70 · The diagram shows how sucrose is loaded into a sieve tube element 9700/12 May/June 2013

27 The diagram shows how sucrose is loaded into a sieve tube element. companion cell sieve tube element 1 hydrogen ions move out of the companion cell 3 sucrose molecules move into sucrose molecules move into sucrose molecules move into the sieve tube element the sieve tube element the sieve tube element hydrogen ions move into the companion cell 2 sucrose molecules move into the companion cell What type of transport is used to move the substances in steps 1, 2 and 3? 1 2 3 A active transport active transport diffusion B active transport facilitated diffusion diffusion C facilitated diffusion active transport active transport D facilitated diffusion facilitated diffusion active transport

1 marks

Answer: B

This question in 9700/12 May/June 2013

Q71 · Halophytes are plants that can survive in regions where they are regularly exposed to sea… 9700/12 May/June 2013

28 Halophytes are plants that can survive in regions where they are regularly exposed to sea water. Sea water has a water potential of approximately –2500 kPa. Which adaptation would you expect halophytes to show? A root hair cells with a very high water potential B root hair cells which accumulate salts and other solutes C a high density of stomata that are open most of the time D leaves that have a large surface area and a thick cuticle

1 marks

Answer: B

This question in 9700/12 May/June 2013

Q72 · The diagram shows part of a transverse section of a leaf 9700/13 May/June 2013

25 The diagram shows part of a transverse section of a leaf. Where does evaporation of water occur during transpiration? A D C B

1 marks

Answer: D

This question in 9700/13 May/June 2013

Q73 · A potometer can be used to measure transpiration rates in a plant 9700/13 May/June 2013

27 A potometer can be used to measure transpiration rates in a plant. Why is the plant stem cut under water before attaching to the potometer? A to maintain the turgidity of the xylem vessels B to prevent collapse of the xylem vessels C to stop air entering the xylem vessels D to stop water loss from the xylem vessels

1 marks

Answer: C

This question in 9700/13 May/June 2013

Q74 · Three solutions, with different water potentials (ψ) are listed 9700/13 May/June 2013

28 Three solutions, with different water potentials (ψ) are listed. 1 cortex cell solution 2 endodermal cell solution 3 root hair cell solution Which row has the solutions in order from the least negative ψ to the most negative ψ? highest ψ lowest ψ A 1 2 3 B 2 1 3 C 3 2 1 D 3 1 2

1 marks

Answer: D

This question in 9700/13 May/June 2013

Q75 · The statements describe some of the properties of water 9700/11 Oct/Nov 2013

22 The statements describe some of the properties of water. 1 requires a lot of heat energy to evaporate 2 retains a lot of heat energy 3 is able to form hydrogen bonds with other water molecules 4 is able to form hydrogen bonds with other polar and non-polar molecules Which properties are important for transport in xylem? A 1, 2 and 3 only B 1, 2 and 4 only C 1 and 3 only D 3 and 4 only

1 marks

Answer: D

This question in 9700/11 Oct/Nov 2013

Q76 · Which row is correct? 9700/11 Oct/Nov 2013

23 Which row is correct? needs energy from transfers heat energy carries assimilates ATP A translocation mass flow xylem vessel element B translocation transpiration phloem sieve tube element C transpiration mass flow xylem vessel element D transpiration translocation phloem sieve tube element

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2013

Q77 · An investigation was carried out into the effect of light intensity on the rate of… 9700/11 Oct/Nov 2013

25 An investigation was carried out into the effect of light intensity on the rate of transpiration. All other variables were standardised. A student was asked to explain the results shown in the graph below. 30 25 20 transpiration rate / cm3 h –1 15 10 5 0 0 10 20 30 40 light intensity / arbitrary units (au) Which explanation is correct? A At light intensities above 30 au the stomata close rapidly. B The rate of transpiration increases as the light intensity increases. C The rate of transpiration never falls to 0 cm3 because some stomata are always open. D Water uptake by the plant increases as the light intensity increases from 0 to 30 au.

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2013

Q78 · Different substances, such as sucrose and amino acids, can move in different directions… 9700/11 Oct/Nov 2013

26 Different substances, such as sucrose and amino acids, can move in different directions in the phloem sieve tubes. Which statement explains this? A Active transport occurs in some phloem sieve tubes and mass flow occurs in other phloem sieve tubes. B Both active transport and mass flow occur in each individual phloem sieve tube. C Mass flow occurs in both directions at the same time in each individual phloem sieve tube. D Mass flow occurs in different directions in different phloem sieve tubes at the same time.

1 marks

Answer: D

This question in 9700/11 Oct/Nov 2013

Q79 · Which feature of a plant cell is an adaptation for water uptake from the soil solution? 9700/12 Oct/Nov 2013

22 Which feature of a plant cell is an adaptation for water uptake from the soil solution? A waxy cuticle B large numbers of mitochondria C long, thin extension to the cell D thick cellulose cell wall

1 marks

Answer: C

This question in 9700/12 Oct/Nov 2013

Q80 · A student used a potometer to measure the rate of water loss from a plant by transpiration 9700/12 Oct/Nov 2013

23 A student used a potometer to measure the rate of water loss from a plant by transpiration. The internal diameter of the capillary tube and the distance moved by the bubble in 30 seconds were recorded. The results are shown in the table. internal diameter of distance bubble moved capillary tube / mm in 30 s / mm 1.8 40.0 The volume of water moved = πr2 x distance moved by the bubble. Which calculation correctly shows how to determine the rate of transpiration in mm3 s–1? π (1.82 × 40.0) A 30 B π(1.82 × 40.0) × 30 30 C π (0.9 2 × 40.0) π (0.9 2× 40.0) D 30

1 marks

Answer: D

This question in 9700/12 Oct/Nov 2013

Q81 · Which feature of xylem vessel elements helps the cohesion of water? 9700/12 Oct/Nov 2013

24 Which feature of xylem vessel elements helps the cohesion of water? A lignin forms an incomplete secondary wall B new vessels carry extra water as a plant grows C there are no cross walls between the vessel elements D the vessel elements form narrow tubes

1 marks

Answer: D

This question in 9700/12 Oct/Nov 2013

Q82 · What determines the rate of water movement from the roots to the leaves? 9700/12 Oct/Nov 2013

25 What determines the rate of water movement from the roots to the leaves? A absorption of water through the root hair cells B development of a less negative water potential in the leaves C diffusion of water through the stomata D evaporation of water from the mesophyll cell walls

1 marks

Answer: D

This question in 9700/12 Oct/Nov 2013

Q83 · The photomicrograph shows a transverse section through a leaf 9700/12 Oct/Nov 2013

26 The photomicrograph shows a transverse section through a leaf. ×50 Which features of a xerophytic leaf are visible in this section? 1 sunken stomata 2 two layers of epithelium 3 thick cuticle 4 small surface area to volume A 1 and 2 only B 1 and 3 only C 3 and 4 only D 1, 2, 3 and 4

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2013

Q84 · What is transpiration and which advantage does it give to a plant? 9700/13 Oct/Nov 2013

22 What is transpiration and which advantage does it give to a plant? transpiration advantage to a plant A evaporation of water maintains the from leaf surfaces water potential B evaporation of water stomata are open from leaf surfaces for gas exchange C loss of water vapour maintains the from leaves water potential D loss of water vapour stomata are open from leaves for gas exchange

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2013

Q85 · What occurs in the sieve tube elements of a photosynthesising leaf and an actively… 9700/13 Oct/Nov 2013

24 What occurs in the sieve tube elements of a photosynthesising leaf and an actively growing root? sieve tube elements in leaf sieve tube elements in root A water potential decreases sugars are moved in B water potential decreases sugars are moved out C water potential increases sugars are moved in D water potential increases sugars are moved out

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2013

Q86 · What occurs in the apoplast and symplast pathways? 9700/13 Oct/Nov 2013

25 What occurs in the apoplast and symplast pathways? water enters water moves from water enters cytoplasm through cell to cell through vacuoles cell surface membrane intercellular spaces A apoplast apoplast symplast B apoplast symplast symplast C symplast apoplast apoplast D symplast symplast apoplast

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2013

Q87 · Some fungi cause wilting in crop plants by growing within the xylem vessels 9700/13 Oct/Nov 2013

26 Some fungi cause wilting in crop plants by growing within the xylem vessels. Which process will be directly affected by these fungi? A cohesion between water molecules B development of root pressure C mass flow during translocation D uptake of water by root hair cells

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2013

Q88 · Which processes are involved in transpiration? 9700/11 May/June 2014

24 Which processes are involved in transpiration? 1 the diffusion of water vapour from stomata 2 the mass flow of water through the xylem 3 the evaporation of water from the surface of mesophyll cells 4 the evaporation of water vapour from air spaces A 1, 2 and 3 B 2, 3 and 4 C 1 and 3 only D 1 and 4

1 marks

Answer: A

This question in 9700/11 May/June 2014

Q89 · The graph shows the results of using a potometer to measure the effect of wind speed on… 9700/11 May/June 2014

26 The graph shows the results of using a potometer to measure the effect of wind speed on the rate of water loss in a plant. 30 25 20 rate of 15 water loss / cm3 hr–1 10 5 0 0 10 20 30 40 wind speed / km hr–1 Which statement explains the results obtained from the investigation? A As wind speed increases, it becomes harder for the plant to obtain carbon dioxide. At high wind speeds the stomata are fully open so rate of water loss is high. B As wind speed increases, moist air around the stomata is removed and replaced by dry air. At high wind speeds the transpiration rate is lower. C As wind speed increases, the rate of water loss increases due to an increased diffusion gradient. At high wind speeds, the stomata close. D As wind speed increases, transpiration rate and rate of photosynthesis increases. At high wind speeds more water is used for photosynthesis.

1 marks

Answer: C

This question in 9700/11 May/June 2014

Q90 · Land flooded by the sea is not suitable for growing plants after the salty flood water… 9700/11 May/June 2014

27 Land flooded by the sea is not suitable for growing plants after the salty flood water has drained away. Which values of water potential in the xylem and soil water help to explain why the land flooded with salty water is unsuitable for growth of plants? water potential / kPa xylem soil water A –1800 –700 B –700 –1800 C –700 –300 D 0 –1800

1 marks

Answer: B

This question in 9700/11 May/June 2014

Q91 · What is the role of ATP in a companion cell when sucrose is loaded into a sieve tube… 9700/11 May/June 2014

28 What is the role of ATP in a companion cell when sucrose is loaded into a sieve tube element? A moving sucrose into the sieve tube element B removing protons out of the cytoplasm of the companion cell C removing protons from the sieve tube element D taking up sucrose into the cytoplasm of the companion cell

1 marks

Answer: B

This question in 9700/11 May/June 2014

Q92 · Which feature of xylem vessel elements helps adhesion during transpiration? 9700/12 May/June 2014

23 Which feature of xylem vessel elements helps adhesion during transpiration? A lignin forms an incomplete secondary wall B new vessels carry extra water as the plants grow C there are no cross walls between vessel elements D the vessel elements form a narrow tube

1 marks

Answer: D

This question in 9700/12 May/June 2014

Q93 · The diagram represents part of the phloem pathway, with adjacent cells, from leaf to root… 9700/12 May/June 2014

24 The diagram represents part of the phloem pathway, with adjacent cells, from leaf to root in a plant. 2 leaf cell 1 chloroplast parenchyma cell nucleus companion cell root cell Which process is occurring between 1 to 2 and what is the effect on the water potential at 2? process from 1 to 2 water potential at 2 A active transport of sucrose becomes less negative B active transport of sucrose becomes more negative C diffusion of sucrose becomes less negative D diffusion of sucrose becomes more negative

1 marks

Answer: B

This question in 9700/12 May/June 2014

Q94 · Which xerophytic adaptations reduce the water potential gradient? 9700/12 May/June 2014

25 Which xerophytic adaptations reduce the water potential gradient? 1 rolled leaves 2 hairy leaves 3 sunken stomata 4 fewer stomata 5 fleshy leaves A 1, 2, 3, 4 and 5 B 1, 2 and 3 only C 1, 3 and 4 only D 2 and 5 only

1 marks

Answer: B

This question in 9700/12 May/June 2014

Q95 · In which combination of environmental conditions are the stomata of a plant most likely… 9700/13 May/June 2014

25 In which combination of environmental conditions are the stomata of a plant most likely to close? atmospheric soil water wind humidity potential speed A high low high B high low low C low high high D low low high

1 marks

Answer: D

This question in 9700/13 May/June 2014

Q96 · What changes occur to the water potential and the volume of liquid in the phloem when… 9700/13 May/June 2014

28 What changes occur to the water potential and the volume of liquid in the phloem when carbohydrate is moved into a sink? water potential volume of liquid A lowers decreases B lowers increases C raises decreases D raises increases

1 marks

Answer: C

This question in 9700/13 May/June 2014

Q97 · Some plant species can take up heavy metal contaminants that are dissolved in soil water… 9700/13 May/June 2014

29 Some plant species can take up heavy metal contaminants that are dissolved in soil water and then transport them within the plant. Within plant cells, the heavy metals accumulate mainly in the vacuole. Which are valid suggestions about the transport and accumulation of heavy metals? 1 After initial entry into the root, some of the heavy metals can pass through the tonoplast to be stored in the vacuole of cortical cells. 2 The heavy metals take an apoplastic pathway in the xylem but at the endodermis must take a symplastic pathway. 3 The rate of accumulation of the heavy metals in leaf cells will be faster at night, when photosynthesis is not occurring, than during the day. 4 The presence of the heavy metal will inhibit active transport, causing the transpiration stream to slow down and reduce the rate of transpiration. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

1 marks

Answer: A

This question in 9700/13 May/June 2014

Q98 · What is the main function of a companion cell in phloem tissue? 9700/11 Oct/Nov 2014

21 What is the main function of a companion cell in phloem tissue? A providing cytoplasmic contact with the sieve tube element for loading B providing structural support for the sieve tube element C providing the nucleus for cell division in the phloem D providing the source of assimilates for storage

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2014

Q99 · How does sucrose move from chloroplasts to the phloem? 9700/11 Oct/Nov 2014

22 How does sucrose move from chloroplasts to the phloem? 1 mass flow 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

1 marks

Answer: D

This question in 9700/11 Oct/Nov 2014

Q100 · A large number of aphids were used to collect samples of the contents of the sieve tube… 9700/11 Oct/Nov 2014

23 A large number of aphids were used to collect samples of the contents of the sieve tube elements of a tomato plant. sieve tube element sample taken micropipette tomato plant stem (aphid and stem are not drawn to the same scale) Different samples of the sieve tube solution were tested. Which was the correct result? Benedict’s test iodine solution before hydrolysis after hydrolysis A blue blue blue - black B blue red orange C red blue blue - black D red red orange

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2014

Q101 · A leafy shoot was attached to a potometer and exposed to a variety of conditions 9700/12 Oct/Nov 2014

25 A leafy shoot was attached to a potometer and exposed to a variety of conditions. The time taken for the meniscus to move 50 mm along the capillary tubing was recorded for each set of conditions. time taken to temperature air humidity move 50 mm / °C movement / s 20 dry still 125 20 dry moving 71 30 dry still 40 20 humid still 166 20 humid moving 83 30 humid still 55 Which shows the slowest and fastest rates of water uptake? slowest fastest / mm s–1 / mm s–1 A 0.3 1.3 B 0.3 3.3 C 3.3 0.3 D 1.3 0.8

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2014

Q102 · How will the root pressure in a plant be affected by waterlogged soil? 9700/12 Oct/Nov 2014

27 How will the root pressure in a plant be affected by waterlogged soil? A It will not be affected. B It will decrease due to a lack of oxygen in the soil. C It will increase due to a lower water potential in the soil. D It will increase due to a higher rate of transpiration.

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2014

Q103 · Which processes occur in the vascular tissue in leaves and in roots? 9700/13 Oct/Nov 2014

22 Which processes occur in the vascular tissue in leaves and in roots? in leaves in roots A sucrose enters phloem water passes from phloem and is polymerised to starch to xylem by osmosis B sucrose enters phloem sucrose is used or polymerised by active transport and the water and the water potential becomes potential becomes more negative less negative C water passes from phloem to active transport of water into the xylem by osmosis, making the phloem xylem makes the water potential water potential less negative more negative D water passes out of xylem and phloem active transport of ions into and is lost through transpiration the xylem makes the water potential less negative

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2014

Q104 · The diagram shows the water potential (Ψ) in some plant cells and in their environment 9700/13 Oct/Nov 2014

23 The diagram shows the water potential (Ψ) in some plant cells and in their environment. cell 1 cell 2 Ψ = Ψ = cell 3 – 5 kPa Ψ = – 7 kPa – 4 kPa environment Ψ = – 5 kPa Which statements are correct? 1 Water moves into and out of all three cells. 2 There is a net movement of water into cell 1. 3 There is no movement of water from the environment to cell 2. 4 Water moves out of cell 1 so it becomes plasmolysed. A 1 and 2 B 1 and 3 C 3 and 4 D 4 only

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2014

Q105 · A region of a plant containing the vascular tissue is treated with a metabolic poison 9700/13 Oct/Nov 2014

24 A region of a plant containing the vascular tissue is treated with a metabolic poison. How will this treatment affect the transport between roots and leaves via xylem and phloem? xylem phloem A v v B v x Cc x v D x x key / = transport continues X = transport stops

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2014

Q106 · A tissue composed of plasmolysed plant cells was put into distilled water 9700/11 May/June 2015

24 A tissue composed of plasmolysed plant cells was put into distilled water. The graph shows how the mean cell volume changes with time. X mean cell volume 0 time What is the cause of the plateau at X? 1 water potential in the plant cell has become more negative 2 cells have become fully turgid 3 no net movement of water into cells A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: D

This question in 9700/11 May/June 2015

Q107 · The diagram shows a vascular bundle from the stem of a plant 9700/11 May/June 2015

25 The diagram shows a vascular bundle from the stem of a plant. 3 2 1 Which row describes the functions of the labelled cells? transports transports stores sucrose ions starch A 1 2 3 B 2 1 3 C 2 3 1 D 3 1 2

1 marks

Answer: B

This question in 9700/11 May/June 2015

Q108 · Which changes to the water potential and the volume of liquid in the phloem occur when… 9700/11 May/June 2015

26 Which changes to the water potential and the volume of liquid in the phloem occur when amino acids are moved into a sink from phloem sieve tubes? water potential volume of liquid in a phloem in phloem sieve sieve tube tubes A higher decreased B higher increased C lower decreased D lower increased

1 marks

Answer: A

This question in 9700/11 May/June 2015

Q109 · What is the sequence of events in the translocation of sucrose? 9700/12 May/June 2015

24 What is the sequence of events in the translocation of sucrose? A active loading of sucrose into sieve elements at the source, increased hydrostatic pressure, mass flow, unloading at the sink B hydrolysis of storage compounds in sinks, lowered water potential, unloading of sucrose from sieve elements, mass flow from the source C lowered pressure in sieve elements at the source, movement of sucrose down the pressure gradient, mass flow down a diffusion gradient to the sink D mass flow of dissolved sucrose into the sieve element at the source, lowered hydrostatic pressure, diffusion of sucrose to sink, active unloading

1 marks

Answer: A

This question in 9700/12 May/June 2015

Q110 · Where does water evaporate from during transpiration? 9700/12 May/June 2015

25 Where does water evaporate from during transpiration? A inside the guard cells B the outer surface of the epidermal cell layer C the sub-stomatal cavity D the surface of spongy mesophyll cell walls

1 marks

Answer: D

This question in 9700/12 May/June 2015

Q111 · Which changes to the water potential and the volume of liquid in the phloem occur when… 9700/12 May/June 2015

26 Which changes to the water potential and the volume of liquid in the phloem occur when amino acids are taken out of a sink in a phloem sieve tube? water potential volume of liquid in phloem sieve in phloem sieve tubes tubes A higher decreased B higher increased C lower decreased D lower increased

1 marks

Answer: D

This question in 9700/12 May/June 2015

Q112 · Which force holds water molecules on the surface of cell walls? 9700/13 May/June 2015

23 Which force holds water molecules on the surface of cell walls? A adhesion B capillarity C cohesion D surface tension

1 marks

Answer: A

This question in 9700/13 May/June 2015

Q113 · The statements are about the properties of water 9700/13 May/June 2015

24 The statements are about the properties of water. 1 requires a lot of heat to evaporate 2 holds a lot of heat 3 is able to form hydrogen bonds with other water molecules 4 is able to form hydrogen bonds with other polar molecules Which properties are important for translocation in phloem? A 1 and 2 B 1 and 3 C 2 and 3 D 3 and 4

1 marks

Answer: D

This question in 9700/13 May/June 2015

Q114 · Which changes to the water potential and the volume of liquid in the phloem occur when… 9700/13 May/June 2015

25 Which changes to the water potential and the volume of liquid in the phloem occur when amino acids are moved into a phloem sieve tube at a source? water potential volume of liquid in phloem sieve in phloem sieve tubes tubes A higher decreased B higher increased C lower decreased D lower increased

1 marks

Answer: D

This question in 9700/13 May/June 2015

Q115 · Which feature of transport in xylem depends on the use of energy? 9700/13 May/June 2015

26 Which feature of transport in xylem depends on the use of energy? A mass flow of water to the leaves B osmosis of water into xylem C uptake of ions into the root D transpiration of water from the leaves

1 marks

Answer: C

This question in 9700/13 May/June 2015

Q116 · By which process does sucrose move through phloem sieve tube elements? 9700/11 Oct/Nov 2015

23 By which process does sucrose move through phloem sieve tube elements? A active transport B diffusion C facilitated diffusion D mass flow

1 marks

Answer: D

This question in 9700/11 Oct/Nov 2015

Q117 · The diagram shows the results of an experiment using leaves with the same surface area… 9700/11 Oct/Nov 2015

24 The diagram shows the results of an experiment using leaves with the same surface area from two different species. Each leaf was left on a balance in daylight in a closed room and their mass recorded at 1 hour intervals. mass of leaf leaf 1 leaf 2 0 1 2 3 4 5 time / hours What could explain these results? A Leaf 1 has a thicker cuticle than leaf 2. B Leaf 1 is thinner than leaf 2. C Leaf 2 has stomata protected by hairs and leaf 1 does not. D Leaf 2 has sunken stomata and leaf 1 does not.

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2015

Q118 · Which description of the movement of water through a leaf is not correct? 9700/11 Oct/Nov 2015

25 Which description of the movement of water through a leaf is not correct? A Water evaporates into an air space from the higher water potential in the cell wall of a mesophyll cell. B Water moves from the higher water potential of the cytoplasm of a mesophyll cell to the lower water potential in its cell wall. C Water moves from the lower water potential of a xylem vessel to the higher water potential of a mesophyll cell. D Water vapour diffuses from an air space, through an open stoma, to the lower humidity of the surrounding air.

1 marks

Answer: C

This question in 9700/11 Oct/Nov 2015

Q119 · Which changes to the water potential and the volume of liquid in the phloem occur when… 9700/11 Oct/Nov 2015

26 Which changes to the water potential and the volume of liquid in the phloem occur when carbohydrate is taken out of a root into phloem sieve tubes? water potential in a volume of liquid phloem sieve tube in phloem becomes sieve tubes A less negative decreased B less negative increased C more negative decreased D more negative increased

1 marks

Answer: D

This question in 9700/11 Oct/Nov 2015

Q120 · What is the role of the Casparian strip? 9700/12 Oct/Nov 2015

23 What is the role of the Casparian strip? A to act as a site for active transport of ions into the xylem B to increase root pressure, increasing transpiration C to lower the water potential in the xylem D to prevent water moving back into the cortex from the xylem

1 marks

Answer: D

This question in 9700/12 Oct/Nov 2015

Q121 · Sucrose is loaded into companion cells and phloem sieve tube elements by active transport… 9700/12 Oct/Nov 2015

24 Sucrose is loaded into companion cells and phloem sieve tube elements by active transport and diffusion using transport proteins and plasmodesmata. Which row shows how sucrose is loaded? active transport diffusion transport proteins plasmodesmata A into companion cell into phloem sieve into companion cell into phloem sieve tube element tube element B into companion cell into phloem sieve into phloem sieve into companion cell tube element tube element C into phloem sieve into companion cell into companion cell into phloem sieve tube element tube element D into phloem sieve into companion cell into phloem sieve into companion cell tube element tube element

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2015

Q122 · Which changes to the water potential and the volume of liquid in the phloem occur when… 9700/12 Oct/Nov 2015

25 Which changes to the water potential and the volume of liquid in the phloem occur when sucrose is transferred from leaves into phloem sieve tubes to be transported to a sink? water potential volume of liquid in phloem sieve in phloem tubes becomes sieve tubes A less negative decreased B less negative increased C more negative decreased D more negative increased

1 marks

Answer: D

This question in 9700/12 Oct/Nov 2015

Q123 · The diagram shows the results of an experiment using leaves with the same surface area… 9700/12 Oct/Nov 2015

26 The diagram shows the results of an experiment using leaves with the same surface area from two different species. Each leaf was left on a balance in daylight in a closed room and their mass recorded at 1 hour intervals. mass of leaf leaf X leaf Y 0 1 2 3 4 5 time / hours Which features of leaf X could explain these results? 1 thinner cuticle 2 sunken stomata 3 ability to roll the leaf 4 no trichomes on the leaf A 1 and 3 B 1 and 4 C 2 and 3 D 1 only

1 marks

Answer: C

This question in 9700/12 Oct/Nov 2015

Q124 · The photomicrograph shows a transverse section of a leaf 9700/13 Oct/Nov 2015

23 The photomicrograph shows a transverse section of a leaf. Which cell has the least negative water potential? C B D A

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2015

Q125 · The diagram shows the results of an experiment on transpiration using two different leaves 9700/13 Oct/Nov 2015

24 The diagram shows the results of an experiment on transpiration using two different leaves. Each leaf was left on a balance in daylight in a closed room and their mass recorded at 1 hour intervals. mass of leaf leaf 1 leaf 2 0 1 2 3 4 5 time / hours Which conclusions could be correct? 1 The loss in mass is mainly due to evaporation of water. 2 The stomata in both leaves close after 1 hour. 3 Leaf 1 has a larger surface area than leaf 2. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2015

Q126 · Which processes are involved in the transport of sucrose in plants? 9700/13 Oct/Nov 2015

25 Which processes are involved in the transport of sucrose in plants? 1 active transport 2 mass flow 3 osmosis A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2015

Q127 · Which changes to the water potential and the volume of liquid in the phloem occur when… 9700/13 Oct/Nov 2015

26 Which changes to the water potential and the volume of liquid in the phloem occur when carbohydrate is moved from phloem sieve tubes into a sink? water potential in volume of liquid phloem sieve in phloem tubes becomes sieve tubes A less negative decreased B less negative increased C more negative decreased D more negative increased

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2015

Q128 · Which statement describes movement through a plant in the apoplast pathway? 9700/12 Feb/March 2016

24 Which statement describes movement through a plant in the apoplast pathway? A Water moves through the cell walls. B Water moves through the cytoplasm. C Water moves through the plasmodesmata. D Water moves through the vacuoles.

1 marks

Answer: A

This question in 9700/12 Feb/March 2016

Q129 · Which changes to the water potential and the volume of liquid in the phloem occur when… 9700/12 Feb/March 2016

25 Which changes to the water potential and the volume of liquid in the phloem occur when sucrose is moved from the phloem sieve tube to an actively dividing root tip? water potential in volume of liquid phloem sieve tube in phloem becomes sieve tubes A less negative decreases B less negative increases C more negative decreases D more negative increases

1 marks

Answer: A

This question in 9700/12 Feb/March 2016

Q130 · The diagram shows the results of an experiment using leaves with the same surface area… 9700/12 Feb/March 2016

26 The diagram shows the results of an experiment using leaves with the same surface area from two different species of plant. Each leaf was left on a balance in daylight in a closed room and its mass recorded at 1 hour intervals. mass of leaf leaf 1 leaf 2 0 1 2 3 4 5 6 time / hours Which features of leaf 2 could explain these results? 1 more stomata per unit area of leaf 2 fewer trichomes (hairs) on the leaf 3 sunken stomata 4 thinner cuticle A 1, 2 and 3 B 1, 2 and 4 C 1 and 4 only D 2 and 3 only

1 marks

Answer: B

This question in 9700/12 Feb/March 2016

Q131 · Which evidence supports the cohesion-tension theory for the movement of water in… 9700/12 Feb/March 2016

27 Which evidence supports the cohesion-tension theory for the movement of water in flowering plants? 1 When the rate of transpiration of a tree is at its maximum, the diameter of the trunk is at its minimum. 2 When a plant shoot is removed close to the base of the stem, sap leaks out from the cut. 3 Evaporation of water from a porous pot can exert a force that draws water up a glass tube attached underneath the pot. 4 Droplets of water form at the edge of leaves of plants growing in conditions of soil with high water content and air with high humidity. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

1 marks

Answer: B

This question in 9700/12 Feb/March 2016

Q132 · Water that is present inside a root hair cell may leave the cell and pass to the vascular… 9700/11 May/June 2016

24 Water that is present inside a root hair cell may leave the cell and pass to the vascular tissue. Through which route must the water travel? A apoplast B plasmodesmata C symplast D vacuoles

1 marks

Answer: C

This question in 9700/11 May/June 2016

Q133 · What is a correct definition of the term transpiration? 9700/11 May/June 2016

25 What is a correct definition of the term transpiration? A diffusion of water from intercellular air spaces to the atmosphere where it evaporates B evaporation of water from the leaf surface of a plant via the stomata C loss of water vapour from the aerial parts of a plant to the atmosphere D movement of water from the xylem to the atmosphere through the cell walls only

1 marks

Answer: C

This question in 9700/11 May/June 2016

Q134 · Which changes to the water potential and the volume of liquid in the phloem sieve tube… 9700/11 May/June 2016

26 Which changes to the water potential and the volume of liquid in the phloem sieve tube element occur when sucrose is moved from a photosynthesising leaf into the phloem sieve tube element? water potential volume of liquid in phloem sieve in phloem sieve tube element tube element A higher decreases B higher increases C lower decreases D lower increases

1 marks

Answer: D

This question in 9700/11 May/June 2016

Q135 · Which statement supports the theory of active loading of sucrose into companion cells? 9700/11 May/June 2016

27 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 to the cytoplasm. B The pH decreases in the cytoplasm of the companion cells compared to the cell wall. C The pH decreases in the plasmodesmata between companion cells and sieve tube elements. D The pH decreases in the sieve tube elements compared to the companion cells.

1 marks

Answer: A

This question in 9700/11 May/June 2016

Q136 · The graph shows the diameter of a tree trunk at different times 9700/12 May/June 2016

23 The graph shows the diameter of a tree trunk at different times. X Z diameter of tree trunk Y / arbitrary units 24:00 12:00 24:00 time of day Which statement is correct? A X shows the expansion of the trunk as water fills the xylem during transpiration. B Y shows a reduction in diameter of trunk as water is lost from the xylem due to transpiration. C Y shows a reduction in diameter of trunk due to water held in tension in the xylem. D Z shows the expansion of the trunk as the phloem tissue acts as a sink at night.

1 marks

Answer: C

This question in 9700/12 May/June 2016

Q137 · Some plant species can take up toxic heavy metal ions that are dissolved in water in the… 9700/12 May/June 2016

24 Some plant species can take up toxic heavy metal ions that are dissolved in water in the soil. These ions accumulate in the aerial parts of the plant, which can be harvested and disposed of safely. An investigation was carried out into the ability of a plant species to remove a heavy metal ion from soil. This produced the following observations: • some heavy metal ions accumulated in the cells of the root cortex • within these cells, most of these ions were in the vacuole • in the roots and leaves, the ions were transported dissolved in water. Which suggestions about the transport and accumulation of heavy metals are valid? 1 After initial entry into the root, some of the ions can pass through the tonoplast. 2 In the roots and leaves, the ions pass through a symplastic or apoplastic pathway but at the endodermis they must take a symplastic pathway. 3 In xylem vessels, the ions pass through an apoplastic pathway only. A 1 and 2 B 2 and 3 C 1 only D 3 only

1 marks

Answer: A

This question in 9700/12 May/June 2016

Q138 · The diagram shows the results of an experiment on transpiration using two different leaves 9700/12 May/June 2016

25 The diagram shows the results of an experiment on transpiration using two different leaves. Each leaf was left on a balance in daylight in a closed room and its mass recorded at 1 hour intervals. mass of leaf leaf 1 leaf 2 0 1 2 3 4 5 6 time / hours Which conclusions could be correct? 1 The loss of mass is mainly due to evaporation of water. 2 Most stomata close in both leaves after 1 hour. 3 Leaf 1 has a larger surface area than leaf 2. 4 Leaf 1 has a thicker cuticle than leaf 2. A 1, 2, 3 and 4 B 1, 2 and 4 only C 2 and 3 only D 3 and 4 only

1 marks

Answer: B

This question in 9700/12 May/June 2016

Q139 · Which statement about the transport of sucrose is correct? 9700/12 May/June 2016

26 Which statement about the transport of sucrose is correct? A ATP synthesised by mitochondria of companion cells provides the energy to move sucrose from phloem sieve tube elements in leaves to sinks. B Sucrose moves through plasmodesmata by passive diffusion from mesophyll cells through companion cells to phloem sieve tube elements. C The water potential in phloem sieve tube elements becomes more negative following the entry of sucrose. D Water enters companion cells and hydrostatic pressure builds up to push sucrose into phloem sieve tube elements by mass flow.

1 marks

Answer: C

This question in 9700/12 May/June 2016

Q140 · During transpiration, what is the site of evaporation of water in the leaves? 9700/13 May/June 2016

23 During transpiration, what is the site of evaporation of water in the leaves? A air spaces B guard cell walls C mesophyll cell walls D stomata

1 marks

This question in 9700/13 May/June 2016

Q141 · Water passes across leaf tissues by different routes as a result of: ● differences in… 9700/13 May/June 2016

24 Water passes across leaf tissues by different routes as a result of: ● differences in water potential ● the pull transmitted by cohesive forces between water molecules. The diagram shows three routes by which water can travel. epidermal cuticle cell palisade cell xylem vessel cells of the key spongy route 1 = apoplastic mesophyll route 2 = vacuolar route 3 = symplastic cuticle atmosphere epidermal cell Which row correctly identifies why water passes across leaf tissues by the different routes? differences in pull transmitted by water potential cohesive forces A route 1 routes 2 and 3 B routes 1 and 3 route 2 C route 2 routes 1 and 3 D routes 2 and 3 route 1

1 marks

This question in 9700/13 May/June 2016

Q142 · Which factors contribute to the increase in transpiration rate when the temperature rises? 9700/13 May/June 2016

25 Which factors contribute to the increase in transpiration rate when the temperature rises? 1 concentration of water molecules increases in air spaces due to evaporation 2 increased rate of diffusion as water molecules have more kinetic energy 3 increased hydrogen bonding between water molecules in air spaces A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

This question in 9700/13 May/June 2016

Q143 · ATP is used in companion cells to provide the energy for loading a sieve tube element… 9700/13 May/June 2016

26 ATP is used in companion cells to provide the energy for loading a sieve tube element with sucrose. How does the co-transporter mechanism use this energy? A to pump protons into the sieve tube element B to pump protons out of the companion cell C to pump sucrose into the sieve tube element D to pump sucrose out of the companion cell

1 marks

This question in 9700/13 May/June 2016

Q144 · Which changes to the water potential and the volume of liquid in the phloem sieve tube… 9700/13 May/June 2016

27 Which changes to the water potential and the volume of liquid in the phloem sieve tube element occur when sucrose is moved from the phloem sieve tube element to an actively dividing shoot tip? water potential volume of in phloem liquid in phloem sieve tube sieve tube element element A higher decreases B higher increases C lower decreases D lower increases

1 marks

This question in 9700/13 May/June 2016

Q145 · Which changes to the water potential and the volume of liquid in the phloem occur when… 9700/11 Oct/Nov 2016

23 Which changes to the water potential and the volume of liquid in the phloem occur when carbohydrate is taken out of a sink into a phloem sieve tube element? water potential volume of liquid in phloem sieve in phloem sieve tube element tube element A higher decreases B higher increases C lower decreases D lower increases

1 marks

Answer: D

This question in 9700/11 Oct/Nov 2016

Q146 · A dendrograph records changes in the diameter of a tree 9700/11 Oct/Nov 2016

24 A dendrograph records changes in the diameter of a tree. The diagram shows a dendrograph fixed to a tree. Some results are shown on the chart recording. dendrograph fixed to a tree chart recording tree chart diameter 12 00 24 00 12 00 24 00 12 00 time of day What explains the diameter changes recorded during the day and night? A Adhesion forces decrease during the night. B Cohesive tension forces increase during the day. C Mass flow of sucrose increases during the night. D Root pressure decreases during the day.

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2016

Q147 · Different substances, such as sucrose and amino acids, can move in different directions… 9700/11 Oct/Nov 2016

26 Different substances, such as sucrose and amino acids, can move in different directions in the phloem sieve tube elements. Which statement explains this? A Active transport occurs in some phloem sieve tube elements and mass flow occurs in other sieve tube elements. B Both active transport and mass flow occur in each individual phloem sieve tube element. C Mass flow occurs in both directions at the same time in each individual phloem sieve tube element. D Mass flow occurs in different directions in different phloem sieve tube elements at the same time.

1 marks

Answer: D

This question in 9700/11 Oct/Nov 2016

Q148 · Which describes possible mechanisms by which sucrose is transferred from a mesophyll cell… 9700/11 Oct/Nov 2016

27 Which describes possible mechanisms by which sucrose is transferred from a mesophyll cell into a companion cell? 1 co-transport with the active transport of hydrogen ions 2 co-transport by passive diffusion of hydrogen ions 3 facilitated diffusion through plasmodesmata A 1 and 3 B 2 and 3 C 1 only D 2 only

1 marks

Answer: D

This question in 9700/11 Oct/Nov 2016

Q149 · Which statements about water movement in plants are correct? 9700/13 Oct/Nov 2016

23 Which statements about water movement in plants are correct? 1 Water cannot pass through cellulose. 2 Water cannot pass through lignin. 3 Water cannot pass through the Casparian strip. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2016

Q150 · The diagrams show transverse sections of parts of a plant 9700/13 Oct/Nov 2016

24 The diagrams show transverse sections of parts of a plant. leaf stem root 3 1 4 5 6 2 In the transverse sections, which tissues transport water and which tissues transport sucrose? A 1 water 4 3 sucrose 6 B 2 water 3 4 sucrose 5 C 3 water 5 2 sucrose 6 D 4 water 6 2 sucrose 5

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2016

Q151 · Which diagram represents the effect of atmospheric humidity on the rate of transpiration? 9700/13 Oct/Nov 2016

25 Which diagram represents the effect of atmospheric humidity on the rate of transpiration? A B rate of rate of transpiration transpiration humidity humidity C D rate of rate of transpiration transpiration humidity humidity

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2016

Q152 · Which combination of features is characteristic of a phloem sieve tube element as it… 9700/12 Feb/March 2017

28 Which combination of features is characteristic of a phloem sieve tube element as it unloads into a sink? lignification of water potential the cell wall A higher than sink absent B higher than sink present C lower than sink absent D lower than sink present

1 marks

Answer: A

This question in 9700/12 Feb/March 2017

Q153 · Which statements correctly describe transport pathways in dicotyledonous plants? 9700/12 Feb/March 2017

29 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 be blocked by the tonoplast. 3 In the apoplast pathway, water does not move through plasmodesmata. 4 The apoplast pathway may be blocked by the Casparian strip. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

1 marks

Answer: D

This question in 9700/12 Feb/March 2017

Q154 · Which feature of transport in plants is correct for both xylem and phloem? 9700/12 Feb/March 2017

31 Which feature of transport in plants is correct for both 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.

1 marks

Answer: B

This question in 9700/12 Feb/March 2017

Q155 · What is the main function of a companion cell in phloem tissue? 9700/12 Feb/March 2017

32 What is the main function of a companion cell in phloem tissue? A providing cytoplasmic contact with the sieve tube element for loading B providing structural support for the sieve tube element C providing the nucleus for cell division in the phloem D providing the source of assimilates for storage

1 marks

Answer: A

This question in 9700/12 Feb/March 2017

Q156 · Sucrose moves from a phloem sieve tube element into a root cell 9700/11 May/June 2017

29 Sucrose moves from a phloem sieve tube element into a root cell. Which changes to the water potential and the volume of liquid in the phloem sieve tube element are correct? water potential volume of liquid A becomes higher decreases B becomes higher increases C becomes lower decreases D becomes lower increases

1 marks

Answer: A

This question in 9700/11 May/June 2017

Q157 · Which statements about water movement in plants are correct? 9700/11 May/June 2017

30 Which statements about water movement in plants are correct? 1 Water can pass through cellulose cell walls. 2 Water can pass through lignified cell walls. 3 Water cannot pass through suberin in cell walls. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/11 May/June 2017

Q158 · The photomicrograph is a transverse section of a leaf 9700/11 May/June 2017

31 The photomicrograph is a transverse section of a leaf. 5 4 1 3 2 Which features are characteristic of xerophytes? A 1, 3, 4 and 5 B 1, 2 and 3 C 1, 2 and 5 D 2, 3, 4 and 5

1 marks

Answer: C

This question in 9700/11 May/June 2017

Q159 · A maize crop is successfully growing in a field in which the water potential of the soil… 9700/11 May/June 2017

32 A maize crop is successfully growing in a field in which the water potential of the soil is – 40 KPa. What is the most likely water potential of the cell sap in the root hair cell? A –60 KPa B – 40 KPa C –20 KPa D 0 KPa

1 marks

Answer: A

This question in 9700/11 May/June 2017

Q160 · The graph shows the loss of mass in a potted plant due to transpiration 9700/12 May/June 2017

22 The graph shows the loss of mass in a potted plant due to transpiration. X mass / g time / minutes What could have occurred at point X on the graph? A A plastic bag was placed around the plant. B The lower epidermis was sealed with petroleum jelly. C The plant was placed into a dark cupboard. D Warm moving air was blown over the plant.

1 marks

Answer: D

This question in 9700/12 May/June 2017

Q161 · An aphid, such as a greenfly, uses a tubular mouthpart called a stylet to feed on… 9700/12 May/June 2017

24 An aphid, such as a greenfly, uses a tubular mouthpart called a stylet to feed on nutrients in the plant. It inserts the stylet through the surface of a stem or leaf. When a stylet is cut near the aphid’s head, leaving the stylet in the plant, a liquid with a low water potential continues to flow out of the plant. Which statement explains this? A The stylet is in a phloem sieve tube element in which there is a high concentration of solutes. B The stylet is in a phloem sieve tube element in which there is a low concentration of solutes. C The stylet is in a xylem vessel element in which there is a high concentration of solutes. D The stylet is in a xylem vessel element in which there is a low concentration of solutes.

1 marks

Answer: A

This question in 9700/12 May/June 2017

Q162 · Which statement correctly describes transport pathways in dicotyledonous plants? 9700/12 May/June 2017

25 Which statement correctly describes transport pathways in dicotyledonous plants? A In the apoplast pathway, water may move through plasmodesmata. B In the symplast pathway, water may move through intercellular spaces. C The apoplast pathway may be blocked by the Casparian strip. D The symplast pathway may be blocked by the tonoplast.

1 marks

Answer: C

This question in 9700/12 May/June 2017

Q163 · The diagrams show transverse sections of parts of a plant 9700/13 May/June 2017

22 The diagrams show transverse sections of parts of a plant. leaf stem root Suen - , Oe bet 6 In the transverse sections, which tissues transport most amino acids? 1 2 3 4 5 6 A v x v x x v key B Jv x x Jv x Jv ¥ = transports most amino acids Cc x Jv Jv x Jv x X = does not transport most amino acids D x v x v v x

1 marks

Answer: C

This question in 9700/13 May/June 2017

Q164 · The statements are descriptions of how water moves across the root to the xylem vessel… 9700/13 May/June 2017

23 The statements are descriptions of how water moves across the root to the xylem vessel elements in plants. 1 Water enters the intercellular spaces. 2 Water enters the cytoplasm by osmosis. 3 Water moves from cell to cell through plasmodesmata. 4 Water moves through the cell wall. Which statements are correct for both the apoplast pathway and the symplast pathway? A 1, 2, 3 and 4 B 1, 2 and 3 only C 2 and 4 only D 4 only

1 marks

Answer: D

This question in 9700/13 May/June 2017

Q165 · The diagram shows the tissues involved in the transport of sucrose in a plant 9700/13 May/June 2017

24 The diagram shows the tissues involved in the transport of sucrose in a plant. Where is the highest concentration of sucrose? phloem sieve tube companion element cell B mesophyll cell A root cell C D

1 marks

Answer: B

This question in 9700/13 May/June 2017

Q166 · Which features adapt root hair cells for efficient absorption of water? 9700/13 May/June 2017

25 Which features adapt root hair cells for efficient absorption of water? 1 a large number of mitochondria 2 a large number of protein carriers in the cell surface membrane 3 a large surface area to volume ratio A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 3 only

1 marks

Answer: D

This question in 9700/13 May/June 2017

Q167 · What contributes to the movement of water through the xylem vessel elements? 9700/12 Oct/Nov 2017

26 What contributes to the movement of water through the xylem vessel elements? A cohesion of water molecules through hydrogen bonding B ion movement followed by passive osmosis C negative water potential in the xylem D surface tension at the top of the plant

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2017

Q168 · The diagram shows a xerophytic leaf in different conditions, P and Q 9700/12 Oct/Nov 2017

27 The diagram shows a xerophytic leaf in different conditions, P and Q. X X P Q Which statements about the cells in layer X of the leaf in each of the conditions P and Q are correct? 1 less negative water potential in P than Q 2 cells may be turgid in P and plasmolysed in Q 3 cells less turgid in P than Q 4 no net diffusion of water into X in either P or Q A 1, 2, 3 and 4 B 1, 2 and 4 only C 1 and 4 only D 2 and 3 only

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2017

Q169 · What are features that adapt root hair cells for efficient uptake of mineral ions? 9700/12 Oct/Nov 2017

28 What are features that adapt root hair cells for efficient uptake of mineral ions? 1 a large number of mitochondria 2 a large number of protein carriers in the cell surface membrane 3 a large surface area to volume ratio A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2017

Q170 · The transverse sections of two plant organs are shown 9700/12 Oct/Nov 2017

29 The transverse sections of two plant organs are shown. S Q T R Which pair of tissues contains proton pumps? A Q and S B Q and T C R and S D R and T

1 marks

Answer: C

This question in 9700/12 Oct/Nov 2017

Q171 · Measurements of the stem of a young tree showed that the diameter varied slightly 9700/12 Oct/Nov 2017

30 Measurements of the stem of a young tree showed that the diameter varied slightly. It decreased during the day and increased during the night. Which statement explains these observations? A During the day, cohesion between water molecules and lignin in the walls of the xylem vessels pulls the walls of the vessels inwards. B During the day, the tension developed in a moving column of water molecules reduces the pressure inside the xylem vessels, so that their walls move inwards. C During the night, the adhesion of water molecules to the lignin in the walls of the xylem vessels pushes the walls of the vessels outwards. D During the night, the pressure of the column of water molecules adhering to one another increases and pushes the walls of the xylem vessels outwards.

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2017

Q172 · Which of these statements correctly describe transport pathways in dicotyledonous plants? 9700/13 Oct/Nov 2017

28 Which of these statements correctly describe transport pathways in dicotyledonous plants? 1 In the apoplast pathway, water may move through plasmodesmata. 2 In the symplast pathway, water may move through intercellular spaces. 3 The apoplast pathway may be blocked by the Casparian strip. A 1 and 2 B 1 and 3 C 2 and 3 D 3 only

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2017

Q173 · Mass flow is the bulk movement of materials from one place to another 9700/13 Oct/Nov 2017

29 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 3 vein 4 xylem vessel A 1, 2, 3 and 4 B 1, 2 and 3 only C 1 and 3 only D 2 and 4 only

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2017

Q174 · Amino acids move from a phloem sieve tube element into a root cell 9700/13 Oct/Nov 2017

30 Amino acids move from a phloem sieve tube element into a root cell. Which changes to the water potential and the volume of liquid in the phloem sieve tube element are correct? water potential volume of liquid A becomes higher decreases B becomes higher increases C becomes lower decreases D becomes lower increases

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2017

Q175 · The table shows the volume of water taken up over a 10 minute period for two species of… 9700/13 Oct/Nov 2017

31 The table shows the volume of water taken up over a 10 minute period for two species of plant, X and Y. water uptake / mm3 time / minutes X Y 2 4.2 1.2 4 7.8 2.3 6 10.9 3.7 8 13.3 4.4 10 16.9 4.9 Both plants were tested at the same time, in the same room and using identical potometers. A student concluded that Y was a xerophyte so lost less water. What feature of the experiment could bring this conclusion into doubt? A The student did not control air flow or temperature surrounding the plants. B The student did not leave the plants to acclimatise to their surroundings. C The student did not take measurements at 0 minutes. D The student did not take account of the area of leaves.

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2017

Q176 · The diagrams show transverse sections of parts of a plant 9700/12 Feb/March 2018

27 The diagrams show transverse sections of parts of a plant. Transport tissues are labelled 1 to 6. leaf stem root 3 1 4 5 6 2 Which row shows tissues that mainly transport water and tissues that mainly transport sucrose? mainly transport mainly transport water sucrose A 1 and 3 4 and 6 B 2 and 3 4 and 5 C 3 and 5 2 and 6 D 4 and 6 2 and 3

1 marks

Answer: D

This question in 9700/12 Feb/March 2018

Q177 · What will increase the rate of transpiration? 9700/12 Feb/March 2018

28 What will increase the rate of transpiration? 1 increasing the humidity 2 increasing the light intensity 3 decreasing the temperature 4 decreasing the wind speed A 1, 2 and 3 B 1, 3 and 4 C 2 only D 4 only

1 marks

Answer: C

This question in 9700/12 Feb/March 2018

Q178 · Which properties of water are important for transport in xylem? 9700/12 Feb/March 2018

29 Which properties of water are important for transport in xylem? 1 cohesion 2 adhesion 3 high energy requirement for evaporation 4 good solvent properties A 1, 2 and 4 B 1 and 4 only C 2, 3 and 4 D 2 and 3 only

1 marks

Answer: A

This question in 9700/12 Feb/March 2018

Q179 · What is a function of the hairs (trichomes) on xerophytic leaves? 9700/11 May/June 2018

25 What is a function of the hairs (trichomes) on xerophytic leaves? A adding a waterproof layer B protecting the stomata C reducing the surface area D trapping a layer of moist air

1 marks

Answer: D

This question in 9700/11 May/June 2018

Q180 · Which features of companion cells are essential to their function? 9700/11 May/June 2018

26 Which features of companion cells are essential to their function? 1 They are connected by plasmadesmata to the sieve tube elements. 2 They have a thinner cell wall than a sieve tube element. 3 They contain a nucleus and mitochondria. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: C

This question in 9700/11 May/June 2018

Q181 · What is the role of ATP in a companion cell when sucrose is loaded into a sieve tube… 9700/12 May/June 2018

26 What is the role of ATP in a companion cell when sucrose is loaded into a sieve tube element? A moving sucrose into the sieve tube element B removing protons from the sieve tube element C removing protons out of the cytoplasm of the companion cell D taking up sucrose into the cytoplasm of the companion cell

1 marks

Answer: C

This question in 9700/12 May/June 2018

Q182 · A potometer was used to measure the transpiration rate of a leafy shoot 9700/12 May/June 2018

27 A potometer was used to measure the transpiration rate of a leafy shoot. What could be the correct units? A cm min B cm2 min–1 C cm3 g–1 min D cm3 min–1

1 marks

Answer: D

This question in 9700/12 May/June 2018

Q183 · Which combination of features is characteristic of a phloem sieve tube element as it is… 9700/12 May/June 2018

28 Which combination of features is characteristic of a phloem sieve tube element as it is loaded from a source? water potential of lignification of the phloem sieve the cell wall tube element A higher than source absent B higher than source present C lower than source absent D lower than source present

1 marks

Answer: C

This question in 9700/12 May/June 2018

Q184 · Which of the processes involved in water movement through xylem vessels depends on… 9700/13 May/June 2018

28 Which of the processes involved in water movement through xylem vessels depends on hydrogen bonding between water molecules? A adhesion B cohesion C evaporation D hydrostatic pressure

1 marks

Answer: B

This question in 9700/13 May/June 2018

Q185 · Which statements about water movement in plants are correct? 9700/13 May/June 2018

29 Which statements about water movement in plants are correct? 1 Water can pass through cellulose. 2 Water cannot pass through lignin. 3 Water can pass through suberin. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: B

This question in 9700/13 May/June 2018

Q186 · Which statements correctly describe transport pathways in dicotyledonous plants? 9700/11 Oct/Nov 2018

24 Which statements correctly describe transport pathways in dicotyledonous plants? 1 In the apoplast pathway, water does not move through plasmodesmata. 2 In the symplast pathway, water does not move through intercellular spaces. 3 The apoplast pathway may be blocked by the Casparian strip. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2018

Q187 · Which properties of water molecules are important in the upward flow of water through… 9700/11 Oct/Nov 2018

26 Which properties of water molecules are important in the upward flow of water through xylem? 1 Water molecules are attracted to each other by hydrogen bonding. 2 Water molecules are attracted to cellulose by adhesion. 3 Water molecules have high cohesion in water columns. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2018

Q188 · What is correct for a phloem sieve tube element that is unloading to a sink? 9700/11 Oct/Nov 2018

27 What is correct for a phloem sieve tube element that is unloading to a sink? water potential of the lignification of phloem sieve tube the cell wall element becomes A less negative than sink absent B less negative than sink present C more negative than sink absent D more negative than sink present

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2018

Q189 · Which statement concerning transpiration is correct? 9700/11 Oct/Nov 2018

28 Which statement concerning transpiration is correct? A On a humid day, the water potential gradient between the intercellular air space and the external atmosphere increases to stimulate water loss by evaporation. B Water arriving at the spongy mesophyll cells via the symplast pathway must move by osmosis through the cell surface membrane before evaporation from the surface of the cells. C Water diffuses down the water potential gradient from the saturated air space through the guard cells before evaporating from the surface of the cells into the atmosphere. D Water moves up the xylem in the apoplast pathway and can continue on this pathway by osmosis to reach the spongy mesophyll cells before evaporating into the intercellular air space.

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2018

Q190 · The diagram shows a xylem vessel in a root and four adjacent parenchyma cells 9700/12 Oct/Nov 2018

18 The diagram shows a xylem vessel in a root and four adjacent parenchyma cells. As water moves up the xylem vessel, it is replaced by water from cell D. Water in cell D is replaced by water in cell C, resulting in a flow of water from cell A to the xylem. Which cell has the least negative water potential? xylem A B C D

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2018

Q191 · Which statement correctly describes an event in the process of mass flow in phloem sieve… 9700/12 Oct/Nov 2018

27 Which statement correctly describes an event in the process of mass flow in phloem sieve tube elements? A Any part of a plant where sucrose is loaded into a sieve tube element is called a sink. B Loading sucrose into a sieve tube element increases the water potential inside it. C Mass flow in the phloem is a passive process occurring at the same rate as diffusion. D Sucrose moves down a hydrostatic pressure gradient in the phloem from source to sink.

1 marks

Answer: D

This question in 9700/12 Oct/Nov 2018

Q192 · The diagram shows a potato tuber at different stages 9700/12 Oct/Nov 2018

28 The diagram shows a potato tuber at different stages. 1 dormant tuber (not growing) 2 sprouting roots and shoots 3 growing roots and shoots 4 making new potato tubers 1 2 3 4 Which row identifies a stage where a potato tuber acts as a source and a stage where it acts as a sink? source sink A 1 3 B 2 4 C 3 2 D 4 1

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2018

Q193 · By which process would water rise up through xylem vessels in a plant root when the shoot… 9700/13 Oct/Nov 2018

26 By which process would water rise up through xylem vessels in a plant root when the shoot has been removed? A capillarity, root pressure and transpiration pull B capillarity and root pressure only C capillarity and transpiration pull only D root pressure only

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2018

Q194 · Which changes occur to the water potential and the volume of liquid in the phloem sieve… 9700/13 Oct/Nov 2018

27 Which changes occur to the water potential and the volume of liquid in the phloem sieve tube element when carbohydrate is moved into a sink? water potential volume of liquid of the sieve of the sieve tube element tube element A lowers decreases B lowers increases C raises decreases D raises increases

1 marks

Answer: C

This question in 9700/13 Oct/Nov 2018

Q195 · The graph shows the diameter of a tree trunk over time 9700/13 Oct/Nov 2018

28 The graph shows the diameter of a tree trunk over time. diameter of tree trunk 12:00 00:00 12:00 00:00 12:00 time of day Which statement explains these changes? A Cohesive tension forces increased during the day. B Columns of water break up during the day. C Mass flow of sucrose decreased during the day. D Root pressure increased during the day.

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2018

Q196 · Which terms describe the method by which water is transported within xylem vessel… 9700/12 Feb/March 2019

23 Which terms describe the method by which water is transported within xylem vessel elements? 1 mass flow 2 cohesion-tension 3 osmosis A 1 and 2 B 1 and 3 C 2 only D 3 only

1 marks

Answer: A

This question in 9700/12 Feb/March 2019

Q197 · Which combination of features is characteristic of a phloem sieve tube element as it is… 9700/12 Feb/March 2019

24 Which combination of features is characteristic of a phloem sieve tube element as it is loaded from a source? water potential of the lignification of the cell wall phloem sieve tube element A less negative than source absent B less negative than source present C more negative than source absent D more negative than source present

1 marks

Answer: C

This question in 9700/12 Feb/March 2019

Q198 · A heating sleeve was placed around the trunk of a small tree at a height of 1m above the… 9700/12 Feb/March 2019

27 A heating sleeve was placed around the trunk of a small tree at a height of 1m above the ground. This allowed a narrow region of the tree trunk to be heated to 60°C. How will heating this region to 60°C affect the transport of phloem sap and xylem sap between the roots and leaves? movement of movement of phloem sap xylem sap A J Jv B Jv x Cc x v D x x key / = transport continues X = transport stops

1 marks

Answer: C

This question in 9700/12 Feb/March 2019

Q199 · Which statement correctly describes a transport pathway in plants? 9700/11 May/June 2019

29 Which statement correctly describes a transport pathway in plants? A In the apoplast pathway, water may move through plasmodesmata. B In the symplast pathway, water may move through intercellular spaces. C The apoplast pathway may be blocked by the Casparian strip. D The symplast pathway may be blocked by the tonoplast.

1 marks

Answer: C

This question in 9700/11 May/June 2019

Q200 · What is correct for phloem sieve tube elements? 9700/12 May/June 2019

22 What is correct for phloem sieve tube elements? A Companion cells provide structural support to the phloem sieve tube elements. B Lignified walls of phloem sieve tube elements prevent transport of mineral salts by mass flow. C Phloem sieve tube elements become narrower as movement of sucrose occurs. D Plasmodesmata allow movement of water and solutes across cell walls of phloem sieve tube elements.

1 marks

Answer: D

This question in 9700/12 May/June 2019

Q201 · The statements are descriptions of how water moves across the root to the xylem vessel… 9700/12 May/June 2019

24 The statements are descriptions of how water moves across the root to the xylem vessel elements. 1 Water enters cell walls. 2 Water enters cytoplasm by osmosis. 3 Water moves from cell to cell through plasmodesmata. 4 Water moves through cell walls. Which statements describe the apoplast pathway? A 1, 2, 3 and 4 B 1, 2 and 3 only C 1 and 4 only D 4 only

1 marks

Answer: C

This question in 9700/12 May/June 2019

Q202 · Four plants, A, B, C and D, were grown in the same conditions and their transpiration… 9700/12 May/June 2019

25 Four plants, A, B, C and D, were grown in the same conditions and their transpiration rates measured. Which plant is most likely to be a xerophyte? transpiration A rate / mg cm–2 B C D 00:00 12:00 24:00 time of day / hours

1 marks

Answer: D

This question in 9700/12 May/June 2019

Q203 · Sucrose moves from a mesophyll cell in a leaf into a phloem sieve tube element 9700/12 May/June 2019

26 Sucrose moves from a mesophyll cell in a leaf into a phloem sieve tube element. Which changes to the water potential and the volume of liquid in the phloem sieve tube element are correct? water potential volume of liquid becomes A less negative decreases B less negative increases C more negative decreases D more negative increases

1 marks

Answer: D

This question in 9700/12 May/June 2019

Q204 · The photomicrograph shows a transverse section through part of a plant root 9700/13 May/June 2019

31 The photomicrograph shows a transverse section through part of a plant root. Which tissue inhibits the path of water through the apoplastic pathway? D A B C

1 marks

Answer: B

This question in 9700/13 May/June 2019

Q205 · Which row correctly describes the adaptations of companion cells, phloem sieve tube… 9700/11 Oct/Nov 2019

25 Which row correctly describes the adaptations of companion cells, phloem sieve tube elements and xylem vessel elements for their roles? companion cell phloem sieve tube element xylem vessel element A a thin layer of cytoplasm strong, lignified cell walls many plasmodesmata to reduce resistance to flow for supporting the plant for communication between cells B empty cells allowing many plasmodesmata strong, lignified cell walls water to flow freely for communication for supporting the plant between cells C many plasmodesmata a thin layer of cytoplasm empty cells allowing for communication to reduce resistance to flow water to flow freely between cells D strong, lignified cell walls empty cells allowing a thin layer of cytoplasm for supporting the plant water to flow freely to reduce resistance to flow

1 marks

Answer: C

This question in 9700/11 Oct/Nov 2019

Q206 · Irrigating crop plants with water containing low concentrations of salt causes an… 9700/11 Oct/Nov 2019

26 Irrigating crop plants with water containing low concentrations of salt causes an increase in the concentration of salt in the soil. What explains why the increase in salt concentration could eventually kill the crop? water potential water potential direction of water in roots in soil movement A decreases out of the roots B increases into the roots C decreases out of the roots D increases into the roots

1 marks

Answer: C

This question in 9700/11 Oct/Nov 2019

Q207 · The diagram shows the pathway of water across root cells to the xylem 9700/11 Oct/Nov 2019

27 The diagram shows the pathway of water across root cells to the xylem. Which cell is in the endodermis? A B C D xylem

1 marks

Answer: C

This question in 9700/11 Oct/Nov 2019

Q208 · Which row shows the cause of mass flow in the phloem and the direction of movement of… 9700/11 Oct/Nov 2019

28 Which row shows the cause of mass flow in the phloem and the direction of movement of phloem sap by mass flow? cause of mass flow direction of movement in the phloem of phloem sap by mass flow A hydrostatic pressure gradient sink to source B hydrostatic pressure gradient source to sink C water potential gradient sink to source D water potential gradient source to sink

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2019

Q209 · The photomicrograph shows a vascular bundle 9700/12 Oct/Nov 2019

24 The photomicrograph shows a vascular bundle. 1 3 2 Which describes the relationship of water potential in the labelled cells? A Cell 3 is less negative than cell 1. B Cell 2 is less negative than cell 3. C Cell 3 is more negative than cells 1 and 2. D Cells 1, 2 and 3 have the same water potential.

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2019

Q210 · Which features have a role in the transport of water in xylem vessel elements? 9700/12 Oct/Nov 2019

25 Which features have a role in the transport of water in xylem vessel elements? 1 capillary action 2 cohesion 3 hydrogen bonding A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 3 only

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2019

Q211 · What is a definition of transpiration? 9700/12 Oct/Nov 2019

26 What is a definition of transpiration? A the evaporation of water vapour from a leaf due to the diffusion of water from an area of low water potential to high water potential B the loss of water vapour from a plant to its environment by diffusion down a water potential gradient C the movement of water from root to leaf due to the adhesion of water molecules to one another D the uptake of water by plant roots by movement of water down a continuous water potential gradient from air to soil

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2019

Q212 · What causes water to move from the root hair cells to the endodermis? 9700/13 Oct/Nov 2019

25 What causes water to move from the root hair cells to the endodermis? A diffusion through cell walls, osmosis down a water potential gradient in the cytoplasm B diffusion through the symplast, osmosis and root pressure through the apoplast C osmosis from cell vacuole to cell vacuole, active transport into the endodermis D osmosis through the intercellular spaces, diffusion in cell walls and cytoplasm

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2019

Q213 · What is true about a Casparian strip? 9700/13 Oct/Nov 2019

26 What is true about a Casparian strip? location formed from effect A cell wall of cortical cell lignin closes symplastic pathway B cell wall of endodermis cell suberin closes apoplastic pathway C cytoplasm of cortical cell lignin closes apoplastic pathway D cytoplasm of endodermis cell suberin closes symplastic pathway

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2019

Q214 · Which xerophytic adaptations reduce the water potential gradient between leaf surface and… 9700/13 Oct/Nov 2019

27 Which xerophytic adaptations reduce the water potential gradient between leaf surface and atmosphere? 1 rolled leaves 2 hairy leaves 3 sunken stomata 4 fewer stomata 5 fleshy leaves A 1, 2, 3, 4 and 5 B 1, 2 and 3 only C 1, 3 and 4 only D 2 and 5 only

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2019

Q215 · When sucrose is loaded into the phloem it has to travel from mesophyll cells to a… 9700/13 Oct/Nov 2019

28 When sucrose is loaded into the phloem it has to travel from mesophyll cells to a companion cell and then into the phloem. In many plants, proton pumps and co-transporter molecules are involved in this process. Which row shows the relative concentrations of sucrose in each type of cell? relative concentration of sucrose / arbitrary units mesophyll companion phloem sieve cell cell tube element A 5 10 15 B 5 15 10 C 15 10 5 D 15 5 10

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2019

Q216 · Hydrogen bonding explains many of the properties of water, including the high latent heat… 9700/12 Feb/March 2020

12 Hydrogen bonding explains many of the properties of water, including the high latent heat of vapourisation and high specific heat capacity. For which processes in plants is hydrogen bonding in water important on hot sunny days? 1 preventing denaturation of enzymes in leaves 2 reducing water loss by evaporation 3 allowing leaves to cool down quickly at night 4 holding the column of water in xylem vessels together A 1, 2, 3 and 4 B 1, 2 and 4 only C 1, 3 and 4 only D 2 and 3 only

1 marks

Answer: B

This question in 9700/12 Feb/March 2020

Q217 · What is correct about the apoplastic pathway and symplastic pathway in a root? 9700/12 Feb/March 2020

26 What is correct about the apoplastic pathway and symplastic pathway in a root? apoplastic pathway symplastic pathway A Casparian strip blocks water moves across the the movement of water root through cell walls B water moves across the water moves from cell to root through cell walls cell via the plasmodesmata C water moves from cell to water passes through cell via the plasmodesmata the cytoplasm D water passes through Casparian strip blocks the cytoplasm the movement of water

1 marks

Answer: B

This question in 9700/12 Feb/March 2020

Q218 · Sucrose moves into a phloem sieve tube element from a leaf mesophyll cell 9700/12 Feb/March 2020

27 Sucrose moves into a phloem sieve tube element from a leaf mesophyll cell. Which changes to the water potential and the volume of solution in the phloem sieve tube element are correct? water potential volume of becomes solution A higher decreases B higher increases C lower decreases D lower increases

1 marks

Answer: D

This question in 9700/12 Feb/March 2020

Q219 · A number of processes contribute to maintaining a water potential gradient in plants… 9700/11 May/June 2020

25 A number of processes contribute to maintaining a water potential gradient in plants allowing water to reach the highest parts of a plant. Which processes are responsible for maintaining this water potential gradient? 1 capillarity 2 osmosis 3 transpiration A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/11 May/June 2020

Q220 · What is a correct statement about the movement of substances absorbed by roots? 9700/11 May/June 2020

26 What is a correct statement about the movement of substances absorbed by roots? A Ions have to pass through cell walls to cross the endodermis. B Ions move through the symplastic pathway only until they reach the Casparian strip. C Soil water has a more negative water potential than the xylem sap. D Water passes through the symplastic pathway along a water potential gradient.

1 marks

Answer: D

This question in 9700/11 May/June 2020

Q221 · Which arrangement of four molecules of water shows how water may cohere when moving up a… 9700/11 May/June 2020

27 Which arrangement of four molecules of water shows how water may cohere when moving up a xylem vessel? A B key oxygen atom hydrogen atom hydrogen bond C D

1 marks

Answer: B

This question in 9700/11 May/June 2020

Q222 · Which statement about sucrose loading into companion cells and then into the phloem sieve… 9700/11 May/June 2020

28 Which statement about sucrose loading into companion cells and then into the phloem sieve tube element is not correct? A Hydrogen ions and sucrose molecules move into the companion cells using a carrier protein. B Hydrogen ions are pumped out of the companion cells by active transport. C Sucrose molecules are carried into the companion cells down the concentration gradient for sucrose. D Sucrose molecules move from a companion cell into the sieve tubes of the phloem through plasmodesmata.

1 marks

Answer: C

This question in 9700/11 May/June 2020

Q223 · External factors change the rate of transpiration, which also affects the water potential… 9700/12 May/June 2020

25 External factors change the rate of transpiration, which also affects the water potential gradient of cells in the leaf. Which combination is correct? external factor changing the water potential gradient rate of transpiration in the leaf A decreasing temperature increases B decreasing wind speed increases C increasing relative humidity decreases D increasing sunlight decreases

1 marks

Answer: C

This question in 9700/12 May/June 2020

Q224 · Which changes occur as carbohydrates move out of a root cell into a phloem sieve tube? 9700/12 May/June 2020

27 Which changes occur as carbohydrates move out of a root cell into a phloem sieve tube? water potential in a volume of liquid phloem sieve tube in phloem becomes sieve tube A less negative decreases B less negative increases C more negative decreases D more negative increases

1 marks

Answer: D

This question in 9700/12 May/June 2020

Q225 · The circumference of a tree stem was measured continually for 48 hours 9700/13 May/June 2020

26 The circumference of a tree stem was measured continually for 48 hours. The results are shown on the chart recording. circumference of tree stem 12 00 24 00 12 00 24 00 12 00 time of day What explains the changes in circumference recorded during the 48 hours? A Adhesion forces decrease during the night. B Cohesive tension forces increase during the day. C Mass flow of sucrose increases during the night. D Root pressure decreases during the day.

1 marks

Answer: B

This question in 9700/13 May/June 2020

Q226 · Which description of movement in phloem is correct? 9700/13 May/June 2020

27 Which description of movement in phloem is correct? A Adding sucrose to a sieve tube element increases its water potential so that water enters and increases the hydrostatic pressure. B At a sink, such as a storage organ, sucrose is removed from a sieve tube element and polymerised into starch. C At a source, such as a photosynthesising leaf, sucrose enters a sieve tube element by facilitated diffusion. D At a source, sucrose is loaded into a companion cell using a protein that carries both hydrogen ions and sucrose molecules.

1 marks

Answer: D

This question in 9700/13 May/June 2020

Q227 · Some fungi cause wilting in crop plants by growing within the xylem vessel elements 9700/11 Oct/Nov 2020

24 Some fungi cause wilting in crop plants by growing within the xylem vessel elements. Which process will be directly affected by these fungi? A cohesion between water molecules B development of root pressure C mass flow during movement of assimilates D uptake of water by root hair cells

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2020

Q228 · Which features have a role in the transport of water in xylem vessel elements? 9700/11 Oct/Nov 2020

25 Which features have a role in the transport of water in xylem vessel elements? 1 capillary action 2 adhesion 3 hydrogen bonding A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2020

Q229 · The loading of sucrose into companion cells involves a number of processes 9700/11 Oct/Nov 2020

26 The loading of sucrose into companion cells involves a number of processes. Which process is active? A the movement of hydrogen ions into the cytoplasm of companion cells B the movement of hydrogen ions out of the cytoplasm of companion cells C the movement of sucrose into companion cells D the movement of sucrose out of companion cells

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2020

Q230 · The statements describe events that occur during the movement of sucrose 9700/11 Oct/Nov 2020

27 The statements describe events that occur during the movement of sucrose. 1 Hydrostatic pressure is decreased. 2 Hydrostatic pressure is increased. 3 Sucrose is loaded into the phloem vessel. 4 Sucrose is unloaded from the phloem vessel. 5 Water moves by osmosis into the phloem. 6 Water moves by osmosis out of the phloem. 7 Water potential decreases in the phloem. 8 Water potential increases in the phloem. Which sequence correctly describes what happens in a plant at a source during the movement of sucrose? A 3  7  5  2 B 3  8  6  1 C 4  7  5  2 D 4  8  6  1

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2020

Q231 · The diameter of a tree trunk usually decreases slightly during the day and increases… 9700/13 Oct/Nov 2020

26 The diameter of a tree trunk usually decreases slightly during the day and increases slightly at night. Which three environmental factors, if increased, could cause the largest decrease in diameter? A humidity, temperature, wind speed B humidity, light intensity, temperature C humidity, light intensity, wind speed D light intensity, temperature, wind speed

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2020

Q232 · Sucrose moves within a phloem sieve tube from a source to a sink by mass flow 9700/13 Oct/Nov 2020

27 Sucrose moves within a phloem sieve tube from a source to a sink by mass flow. Which type of gradient within the phloem sieve tube between the source and sink causes the movement of sucrose? A diffusion gradient B hydrostatic gradient C concentration gradient D water potential gradient

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2020

Q233 · Some of the parts of a plant root involved in water transport are listed 9700/12 Feb/March 2021

25 Some of the parts of a plant root involved in water transport are listed. 1 Casparian strip 2 cell walls of cortex cells 3 endodermal cells 4 epidermal cells 5 xylem vessels Which sequence shows part of a pathway through which water can move across a root? A 2  3  5 B 2  1  5 C 4  2  1 D 4  3  2

1 marks

Answer: A

This question in 9700/12 Feb/March 2021

Q234 · What is an example of a mass flow system in a plant? 9700/12 Feb/March 2021

26 What is an example of a mass flow system in a plant? A the loading of amino acids from the surrounding tissues into companion cells B the movement of sap through the phloem sieve tubes in the stem C the movement of water across the root along the symplastic pathway D the movement of water vapour from the internal spaces in the leaf out through the stomata

1 marks

Answer: B

This question in 9700/12 Feb/March 2021

Q235 · The diameter of a tree trunk usually decreases slightly during the day 9700/12 Feb/March 2021

27 The diameter of a tree trunk usually decreases slightly during the day. Which changes in environmental factors during the day could cause the diameter to decrease even more? increased temperature C A D increased light increased B intensity humidity

1 marks

Answer: A

This question in 9700/12 Feb/March 2021

Q236 · Which statement about the role of co-transporter proteins in the movement of sucrose is… 9700/12 Feb/March 2021

28 Which statement about the role of co-transporter proteins in the movement of sucrose is correct? A Co-transporter proteins pump hydrogen ions into phloem sieve tubes along with sucrose. B Hydrogen ions diffuse through co-transporter proteins with sucrose into companion cells. C Plasmodesmata move sucrose into phloem sieve tubes via co-transporter proteins. D Sucrose is moved through co-transporter proteins by active transport.

1 marks

Answer: B

This question in 9700/12 Feb/March 2021

Q237 · What contributes to the upward movement of water in a xylem vessel of a plant? 9700/11 May/June 2021

23 What contributes to the upward movement of water in a xylem vessel of a plant? 1 cohesion of water molecules by hydrogen bonding 2 adhesion of water molecules to the cellulose walls of xylem vessels by hydrogen bonding 3 removal of water from xylem vessels in a leaf reduces the hydrostatic pressure in the xylem A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/11 May/June 2021

Q238 · The diameter of a tree trunk usually decreases slightly during the day 9700/11 May/June 2021

24 The diameter of a tree trunk usually decreases slightly during the day. Which changes in environmental factors during the day could cause the diameter to decrease even more? increased light intensity C A D increased increased wind speed B temperature

1 marks

Answer: D

This question in 9700/11 May/June 2021

Q239 · Different substances, such as sucrose and amino acids, can move in different directions… 9700/11 May/June 2021

27 Different substances, such as sucrose and amino acids, can move in different directions in the phloem sieve tube elements. Which statement explains this? A Active transport occurs in some phloem sieve tube elements and mass flow occurs in other sieve tube elements. B Both active transport and mass flow occur in each individual phloem sieve tube element. C Mass flow occurs in both directions at the same time in each individual phloem sieve tube element. D Mass flow occurs in different directions in different phloem sieve tube elements at the same time.

1 marks

Answer: D

This question in 9700/11 May/June 2021

Q240 · Which descriptions of the adaptations of xylem vessel elements to their function are… 9700/12 May/June 2021

23 Which descriptions of the adaptations of xylem vessel elements to their function are correct? 1 They have pits between vessels allowing water to pass from one vessel to another. 2 They are thickened with lignin to stop them collapsing when the column of water is under tension. 3 They form a continuous hollow tube through the plant providing little resistance to water movement. A 1, 2 and 3 B 1 and 3 only C 2 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/12 May/June 2021

Q241 · The diameter of a tree trunk usually decreases slightly during the day 9700/12 May/June 2021

24 The diameter of a tree trunk usually decreases slightly during the day. Which changes in environmental factors during the day could cause the diameter to decrease even more? increased humidity C A D increased increased wind speed B light intensity

1 marks

Answer: B

This question in 9700/12 May/June 2021

Q242 · A student wanted to find out the rate of transpiration using a potometer as shown 9700/12 May/June 2021

25 A student wanted to find out the rate of transpiration using a potometer as shown. cut shoot reservoir air bubble capillary tube volume beaker scale of water The student was told to work out a value for transpiration using the units mm3, m–2 and hour–1. Which measurements would the student need to take? A volume of water in the reservoir, length of the capillary tubing, temperature and how many leaves are on the shoot B volume of water in the reservoir, radius of the capillary tubing, time and surface area of the leaves C distance air bubble moves, radius of the capillary tubing, time and surface area of the leaves D distance air bubble moves, length of the capillary tubing, temperature and how many leaves are on the shoot

1 marks

Answer: C

This question in 9700/12 May/June 2021

Q243 · In plants, assimilates such as sucrose are loaded from source cells into sieve tube… 9700/12 May/June 2021

26 In plants, assimilates such as sucrose are loaded from source cells into sieve tube elements. The assimilates are then transported from source to sink. What is needed to transport sucrose from source cells through phloem tissue to sink cells? water potential gradient between A B ATP the source and the sink C D hydrostatic pressure gradient between the source and the sink

1 marks

Answer: C

This question in 9700/12 May/June 2021

Q244 · Which properties of water molecules are important in the upward flow of water through the… 9700/13 May/June 2021

24 Which properties of water molecules are important in the upward flow of water through the xylem? 1 Water molecules are attracted to each other by hydrogen bonding. 2 Water molecules are attracted to cellulose by adhesion. 3 Water molecules have high cohesion in water columns. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/13 May/June 2021

Q245 · The graph shows the rate of water absorption and the rate of water loss by a plant during… 9700/13 May/June 2021

25 The graph shows the rate of water absorption and the rate of water loss by a plant during one 24-hour period. The plant was growing in natural conditions. water loss rate of water absorption or loss water absorption 0 00:00 04:00 08:00 12:00 16:00 20:00 24:00 night day night time What may be concluded from the graph? 1 The rate of water absorption and the rate of water loss peak at 16:00. 2 The rate of water loss is greater than the rate of water absorption for 12 hours. 3 The rate of water absorption is greater than the rate of water loss at night. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/13 May/June 2021

Q246 · Sucrose moves into an actively dividing shoot tip from a phloem sieve tube element 9700/13 May/June 2021

27 Sucrose moves into an actively dividing shoot tip from a phloem sieve tube element. Which changes to the water potential and the volume of liquid in the phloem sieve tube element are correct? water potential volume of liquid becomes A less negative decreases B less negative increases C more negative decreases D more negative increases

1 marks

Answer: A

This question in 9700/13 May/June 2021

Q247 · Sucrose is loaded into phloem sieve tubes from companion cells 9700/13 May/June 2021

28 Sucrose is loaded into phloem sieve tubes from companion cells. What is the correct order of statements that explains this mechanism? 1 Hydrogen ions diffuse into companion cells through co-transporter proteins. 2 Hydrogen ions are pumped out of companion cells by active transport. 3 Sucrose diffuses into phloem sieve tubes via plasmodesmata. 4 Sucrose is co-transported along with hydrogen ions. A 1  2  4  3 B 1  4  2  3 C 2  1  4  3 D 4  1  2  3

1 marks

Answer: C

This question in 9700/13 May/June 2021

Q248 · Water molecules are attracted to each other 9700/11 Oct/Nov 2021

26 Water molecules are attracted to each other. This property is important in the upward movement of water in xylem. Which term is used to describe the attraction of water molecules to each other? A adhesion B cohesion C hydrophilic D polar

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2021

Q249 · The diagram shows a model to demonstrate mass flow 9700/11 Oct/Nov 2021

27 The diagram shows a model to demonstrate mass flow. W water concentrated dilute sucrose solution Y X Z sucrose solution partially permeable partially permeable membrane membrane In a plant, what are the structures W, X, Y and Z and what is the direction of flow of solution along W? phloem xylem roots leaves direction of flow along W A W X Y Z from Z to Y B W X Z Y from Y to Z C X W Y Z from Y to Z D X W Z Y from Z to Y

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2021

Q250 · Which features of companion cells are essential to their function? 9700/12 Oct/Nov 2021

24 Which features of companion cells are essential to their function? 1 They are connected to the sieve tube elements by plasmodesmata. 2 They have a thicker cell wall than a sieve tube element. 3 They contain a nucleus and mitochondria. A 1 and 2 B 1 and 3 C 1 only D 2 and 3

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2021

Q251 · Which statements about water movement in plants are correct? 9700/12 Oct/Nov 2021

25 Which statements about water movement in plants are correct? 1 Water can pass through cellulose cell walls. 2 Water cannot pass through lignified cell walls. 3 Water can pass through cell walls that contain suberin. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2021

Q252 · The diameter of a tree trunk usually decreases slightly during the day 9700/12 Oct/Nov 2021

26 The diameter of a tree trunk usually decreases slightly during the day. Which changes in environmental factors during the day could cause the diameter to decrease even more? increased humidity C A D increased increased wind speed B temperature

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2021

Q253 · Which sequence of events could lead to mass flow in a phloem sieve tube? 9700/12 Oct/Nov 2021

27 Which sequence of events could lead to mass flow in a phloem sieve tube? 1 Sucrose moves into a sieve tube element. 2 Protons (H+) and sucrose molecules move into a companion cell through a co-transporter protein. 3 A very high hydrostatic pressure is produced. 4 The water potential of the sieve tube element decreases. 5 Protons (H+) are actively pumped out of a companion cell. 6 Water moves down a water potential gradient by osmosis. A 1  2  5  6  4  3 B 3  1  2  5  6  4 C 3  5  1  2  4  6 D 5  2  1  4  6  3

1 marks

Answer: D

This question in 9700/12 Oct/Nov 2021

Q254 · The diagram shows a vascular bundle from the stem of a plant 9700/13 Oct/Nov 2021

23 The diagram shows a vascular bundle from the stem of a plant. 3 2 1 Which row describes the functions of the labelled cells? transports transports stores sucrose mineral ions starch A 1 2 3 B 2 1 3 C 2 3 1 D 3 1 2

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2021

Q255 · Which statements explain why transpiration is an inevitable consequence of gas exchange… 9700/13 Oct/Nov 2021

25 Which statements explain why transpiration is an inevitable consequence of gas exchange in plants? 1 Hydrolysis reactions are taking place in cells. 2 ATP production is occurring. 3 Stomata must be open. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 3 only

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2021

Q256 · In an investigation, a leafy shoot was attached to a potometer and exposed to a variety… 9700/13 Oct/Nov 2021

26 In an investigation, a leafy shoot was attached to a potometer and exposed to a variety of conditions. The time taken for the meniscus to move 50 mm along the capillary tubing was recorded for each set of conditions. time taken to temperature air humidity move 50 mm / C movement / s 20 dry not moving 125 20 dry moving 71 30 dry not moving 40 20 humid not moving 166 20 humid moving 83 30 humid not moving 55 Which row shows the slowest and fastest rates of water uptake for this investigation? slowest rate fastest rate / mm s–1 / mm s–1 A 0.3 1.3 B 0.3 3.3 C 3.3 0.3 D 1.3 0.8

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2021

Q257 · Proton pumps (H+ pumps) and co-transporters are used by plants when loading sucrose into… 9700/13 Oct/Nov 2021

27 Proton pumps (H+ pumps) and co-transporters are used by plants when loading sucrose into a phloem sieve tube element at a source. Which row is correct? proton pump co-transporter A pumps protons into a the high concentration of protons in the companion cell raising its pH companion cell allows the transporter to be used for moving sucrose out of the cell B pumps protons into a the high concentration of protons in a mesophyll cell raising its pH mesophyll cell drives the transport of sucrose into the cell C pumps protons out of a the high concentration of protons outside companion cell into its cell wall a companion cell drives the transport of sucrose into the cell D pumps protons out of a the low concentration of protons in a mesophyll cell into its cell wall mesophyll cell allows the transporter to be used for moving sucrose out of the cell

1 marks

Answer: C

This question in 9700/13 Oct/Nov 2021

Q258 · Why does an air bubble in a xylem vessel element stop the flow of water? 9700/12 Feb/March 2022

27 Why does an air bubble in a xylem vessel element stop the flow of water? 1 loss of adhesion 2 loss of cohesion 3 collapse of xylem vessel element A 1, 2 and 3 B 1 and 3 only C 1 only D 2 only

1 marks

Answer: D

This question in 9700/12 Feb/March 2022

Q259 · Which changes to the water potential and the volume of solution in a phloem sieve tube… 9700/12 Feb/March 2022

28 Which changes to the water potential and the volume of solution in a phloem sieve tube occur when amino acids are moved into a sink from the phloem sieve tube? water potential in volume of solution the phloem sieve in the phloem tube becomes sieve tube A higher decreases B higher increases C lower decreases D lower increases

1 marks

Answer: A

This question in 9700/12 Feb/March 2022

Q260 · Which feature of some xerophytic leaves reduces the rate of transpiration by decreasing… 9700/12 Feb/March 2022

29 Which feature of some xerophytic leaves reduces the rate of transpiration by decreasing the water potential gradient between the internal leaf surface and the atmosphere? A a thick waxy cuticle on the upper surface of the leaf B leaves reduced to spines with a small surface area to volume ratio C stomata located in sunken pits on the leaf surface D elongated leaves that are swollen storing large amounts of water

1 marks

Answer: C

This question in 9700/12 Feb/March 2022

Q261 · Which row is correct for the movement of water in a root? 9700/11 May/June 2022

26 Which row is correct for the movement of water in a root? molecule present pathway in Casparian strip A apoplast pathway through intercellular spaces suberin B apoplast pathway through plasmodesmata lignin C symplast pathway through plasmodesmata lignin D symplast pathway through intercellular spaces suberin

1 marks

Answer: A

This question in 9700/11 May/June 2022

Q262 · The table contains some information about uptake and movement of water and of mineral… 9700/11 May/June 2022

27 The table contains some information about uptake and movement of water and of mineral ions in plants. water mineral ions mechanism for uptake osmosis diffusion, active transport site of uptake root hair cells root hair cells mechanism of release evaporation, diffusion diffusion, active transport site of release stomata plant cells Using the information provided, which factors will affect the uptake and movement of water or of mineral ions in plants? 1 humidity 2 surface area of root hair cell 3 oxygen concentration 4 temperature A 1, 2, 3 and 4 B 1, 3 and 4 only C 1 and 3 only D 4 only

1 marks

Answer: A

This question in 9700/11 May/June 2022

Q263 · Which changes to the water potential and the volume of solution in the phloem sieve tube… 9700/11 May/June 2022

28 Which changes to the water potential and the volume of solution in the phloem sieve tube occur when sucrose is moved from a photosynthesising leaf into the phloem sieve tube? water potential in volume of solution the phloem sieve in the phloem tube becomes sieve tube A higher decreases B higher increases C lower decreases D lower increases

1 marks

Answer: D

This question in 9700/11 May/June 2022

Q264 · A student wrote the following statements about a possible mechanism for loading sucrose… 9700/11 May/June 2022

29 A student wrote the following statements about a possible mechanism for loading sucrose from a source. 1 When energy is released from ATP, the released energy is used to move sucrose through a co-transporter protein in the companion cell membrane. 2 As sucrose is moved into a companion cell the pH in the cell wall of the companion cell decreases. 3 Proton pumps in the cell membrane of a companion cell move sucrose into the phloem sieve tube element. Which statements are correct? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 only

1 marks

Answer: D

This question in 9700/11 May/June 2022

Q265 · The diagrams show transverse sections through parts of plants 9700/12 May/June 2022

25 The diagrams show transverse sections through parts of plants. 3 1 4 5 6 2 Which row is correct? transports contains lignin organic solutes A 1, 4, 5 2, 3, 6 B 1, 4, 6 2, 3, 5 C 2, 3, 5 1, 4, 6 D 2, 4, 6 1, 3, 5

1 marks

Answer: B

This question in 9700/12 May/June 2022

Q266 · Which molecules form hydrogen bonds with water during transpiration? 9700/12 May/June 2022

26 Which molecules form hydrogen bonds with water during transpiration? 1 cellulose in the xylem wall 2 suberin in the xylem wall 3 other water molecules in the xylem A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: C

This question in 9700/12 May/June 2022

Q267 · Some plant species can take up heavy metal contaminants that are dissolved in soil water… 9700/12 May/June 2022

27 Some plant species can take up heavy metal contaminants that are dissolved in soil water and then transport them within the plant. Within plant cells, the heavy metals accumulate mainly in the vacuole. Which suggestions about the transport and accumulation of heavy metals are valid? 1 After initial entry into the root, some of the heavy metals can pass through the tonoplast to be stored in the vacuole of cells in the cortex. 2 The heavy metals take an apoplastic pathway in the xylem but at the endodermis must take a symplastic pathway. 3 The rate of accumulation of the heavy metals in leaf cells will be faster at night, when photosynthesis is not occurring, than during the day. 4 The presence of heavy metals causes the transpiration stream to slow down and reduce the rate of transpiration. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

1 marks

Answer: A

This question in 9700/12 May/June 2022

Q268 · What is the correct route for the movement of water from cell to cell in the apoplast… 9700/12 May/June 2022

28 What is the correct route for the movement of water from cell to cell in the apoplast pathway? A through adjacent cell surface membranes B through intercellular spaces C through plasmodesmata D through the Casparian strip

1 marks

Answer: B

This question in 9700/12 May/June 2022

Q269 · Which row shows the correct sequence for the movement of sucrose into phloem sieve tubes? 9700/12 May/June 2022

29 Which row shows the correct sequence for the movement of sucrose into phloem sieve tubes? first second third A diffusion of sucrose into the active transport of protons cotransport of protons and companion cell cytoplasm into the companion sucrose into the sieve tubes cell cytoplasm B cotransport of protons and active transport of protons diffusion of sucrose into sucrose into the companion out of the companion the sieve tubes cell cytoplasm cell cytoplasm C active transport of protons diffusion of sucrose into the cotransport of protons and into the companion companion cell cytoplasm sucrose into the sieve tubes cell cytoplasm D active transport of protons cotransport of protons and diffusion of sucrose into out of the companion sucrose into the companion the sieve tubes cell cytoplasm cell cytoplasm

1 marks

Answer: D

This question in 9700/12 May/June 2022

Q270 · Which changes to the water potential and the volume of solution in the phloem sieve tube… 9700/13 May/June 2022

28 Which changes to the water potential and the volume of solution in the phloem sieve tube element occur when sucrose is moved from the phloem sieve tube element to an actively dividing shoot tip? water potential in volume of solution phloem sieve tube in phloem sieve element becomes tube element A higher decreases B higher increases C lower decreases D lower increases

1 marks

Answer: A

This question in 9700/13 May/June 2022

Q271 · Which processes occur during the loading of sucrose into phloem sieve tubes? 9700/13 May/June 2022

29 Which processes occur during the loading of sucrose into phloem sieve tubes? 1 Protons are pumped out of the cytoplasm of the companion cell into its cell wall. 2 There is a higher concentration of protons in the symplastic pathway outside the companion cell. 3 Protons are unable to move back into the companion cell. 4 A co-transporter molecule acts as a carrier for protons and sucrose. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

1 marks

Answer: B

This question in 9700/13 May/June 2022

Q272 · The electron micrograph shows a cross-section of a leaf vein and some neighbouring cells 9700/11 Oct/Nov 2022

26 The electron micrograph shows a cross-section of a leaf vein and some neighbouring cells. Which structure contributes to mass flow by the use of proton pumps? A B C D

1 marks

Answer: C

This question in 9700/11 Oct/Nov 2022

Q273 · Which row is correct for the sucrose concentrations and the water potentials in a source… 9700/11 Oct/Nov 2022

30 Which row is correct for the sucrose concentrations and the water potentials in a source and a sink in a potato plant, at 12:00 p.m.? sucrose concentration water potential source sink source sink A higher lower higher lower B higher lower lower higher C lower higher higher lower D lower higher lower higher

1 marks

Answer: B

This question in 9700/11 Oct/Nov 2022

Q274 · The diagram shows one possible way in which sucrose may be loaded into a sieve tube… 9700/11 Oct/Nov 2022

31 The diagram shows one possible way in which sucrose may be loaded into a sieve tube element. companion cell 1 protons move out of the companion cell 3 sieve tube element protons move into the companion cell 2 sucrose molecules move into the companion cell Which steps require ATP? A 1 and 2 B 1 and 3 C 1 only D 3 only

1 marks

Answer: C

This question in 9700/11 Oct/Nov 2022

Q275 · Sodium chloride is added to a culture solution containing freshwater single-celled plant… 9700/12 Oct/Nov 2022

27 Sodium chloride is added to a culture solution containing freshwater single-celled plant cells. What happens to the water potential of the culture solution when the sodium chloride is added and what may happen to the plant cells after 5 minutes? water potential of the single-celled plant cells culture solution when after 5 minutes sodium chloride added A becomes less negative become plasmolysed B becomes less negative become turgid C becomes more negative become plasmolysed D becomes more negative become turgid

1 marks

Answer: C

This question in 9700/12 Oct/Nov 2022

Q276 · Which statements correctly describe transport pathways in dicotyledonous plants? 9700/12 Oct/Nov 2022

28 Which statements correctly describe transport pathways in dicotyledonous plants? 1 In the apoplast pathway, water may move through plasmodesmata. 2 In the symplast pathway, water may move through intercellular spaces. 3 The apoplast pathway may be blocked by the Casparian strip. A 1 and 2 B 1 and 3 C 2 and 3 D 3 only

1 marks

Answer: D

This question in 9700/12 Oct/Nov 2022

Q277 · Which statement about the movement of water from roots to leaves is not correct? 9700/12 Oct/Nov 2022

29 Which statement about the movement of water from roots to leaves is not correct? A A continuous column of water is partly maintained by the attraction of water molecules to cellulose. B Hydrogen bonding between water molecules enables mass flow of water. C Hydrostatic pressure in xylem vessel elements is higher in roots than in leaves. D Water potential changes throughout the length of the xylem vessel elements.

1 marks

Answer: D

This question in 9700/12 Oct/Nov 2022

Q278 · Which terms describe the method by which water is transported within xylem vessel… 9700/12 Oct/Nov 2022

30 Which terms describe the method by which water is transported within xylem vessel elements? 1 cotransport 2 cohesion-tension 3 osmosis A 1 and 2 B 1 and 3 C 2 only D 3 only

1 marks

Answer: C

This question in 9700/12 Oct/Nov 2022

Q279 · What is the main function of a companion cell in phloem tissue? 9700/12 Oct/Nov 2022

31 What is the main function of a companion cell in phloem tissue? A providing cytoplasmic contact with the sieve tube element for loading B providing structural support for the sieve tube element C providing the nucleus for cell division in the phloem D providing the source of assimilates for storage

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2022

Q280 · The statements describe some of the properties of water 9700/13 Oct/Nov 2022

27 The statements describe some of the properties of water. 1 requires a lot of heat energy to evaporate 2 retains a lot of heat energy 3 is able to form hydrogen bonds with other water molecules 4 is able to form hydrogen bonds with other polar and non-polar molecules Which properties are also important for transport in xylem? A 1, 2 and 3 B 1, 2 and 4 C 1 and 3 only D 3 and 4

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2022

Q281 · Which xerophytic adaptations reduce the water potential gradient between leaf surface and… 9700/13 Oct/Nov 2022

28 Which xerophytic adaptations reduce the water potential gradient between leaf surface and atmosphere? 1 rolled leaves 2 hairy leaves 3 sunken stomata 4 fewer stomata 5 fleshy leaves A 1, 2, 3, 4 and 5 B 1, 2 and 3 only C 1, 3 and 4 only D 2 and 5 only

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2022

Q282 · The diagram shows seven stages of a tulip bulb’s growth 9700/13 Oct/Nov 2022

29 The diagram shows seven stages of a tulip bulb’s growth. 1 2 3 4 5 6 7 Which row identifies the correct stages in which the tulip bulb is acting as a source only or as a sink only? source sink only only A 1 5 B 3 4 C 4 6 D 5 7

1 marks

Answer: C

This question in 9700/13 Oct/Nov 2022

Q283 · What would be changed if mitochondrial activity was inhibited by a metabolic poison… 9700/13 Oct/Nov 2022

30 What would be changed if mitochondrial activity was inhibited by a metabolic poison acting on cells in the phloem tissue? 1 concentration of hydrogen ions in the cell wall of companion cells 2 concentration of sucrose in the cytoplasm of cells in a leaf 3 hydrostatic pressure gradient in the phloem sieve tube A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2022

Q284 · By which process does sucrose move through phloem sieve tube elements? 9700/13 Oct/Nov 2022

31 By which process does sucrose move through phloem sieve tube elements? A active transport B diffusion C facilitated diffusion D mass flow

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2022

Q285 · Which row correctly matches the structure and function of phloem sieve tube elements? 9700/12 Feb/March 2023

25 Which row correctly matches the structure and function of phloem sieve tube elements? structure function A peripheral cytoplasm to provide as little resistance with no nucleus to flow as possible B end walls modified to to slow down the rate of form sieve plates transport of solutes C elongated cells joined to form a tube to transport end to end dissolved mineral ions and water D cellulose cell wall with no lignin to prevent loss of water

1 marks

Answer: A

This question in 9700/12 Feb/March 2023

Q286 · Which feature of xylem vessel elements helps adhesion during transpiration? 9700/12 Feb/March 2023

26 Which feature of xylem vessel elements helps adhesion during transpiration? A Lignin forms a complete secondary wall. B New vessels carry extra water as the plants grow. C There are no cross walls between vessel elements. D The vessel elements form a narrow tube.

1 marks

Answer: D

This question in 9700/12 Feb/March 2023

Q287 · Mass flow is the bulk movement of materials from one place to another 9700/12 Feb/March 2023

27 Mass flow is the bulk movement of materials from one place to another. How many of the vessels listed carry fluids by mass flow? ● artery ● phloem sieve tube ● vein ● xylem vessel A 1 B 2 C 3 D 4

1 marks

Answer: D

This question in 9700/12 Feb/March 2023

Q288 · Cellulose, lignin and suberin are components of various plant cell walls 9700/12 Feb/March 2023

28 Cellulose, lignin and suberin are components of various plant cell walls. Descriptions of these cell wall components are listed. 1 a component of the Casparian strip 2 redirects water into the symplast pathway 3 a hydrophobic component of cell walls 4 water interacts with this molecule in the apoplast pathway Which row correctly matches three of the descriptions with cell wall components? cellulose lignin suberin A 2 4 1 B 3 4 2 C 4 1 2 D 4 3 1

1 marks

Answer: D

This question in 9700/12 Feb/March 2023

Q289 · The arrows show the direction of water movement across a plant root, from water in the… 9700/12 Feb/March 2023

29 The arrows show the direction of water movement across a plant root, from water in the soil to the xylem. plasmodesmata water 1 3 5 7 8 in soil 2 4 6 xylem Which arrows show water movement only in the apoplast pathway? A 1, 3, 5, 7 and 8 B 2, 4 and 6 C 2 and 4 only D 3, 5 and 7 only

1 marks

Answer: C

This question in 9700/12 Feb/March 2023

Q290 · Which row correctly identifies sources and sinks of sugars? 9700/12 Feb/March 2023

30 Which row correctly identifies sources and sinks of sugars? root cells storage cells of absorbing seed that is mineral ions starting to grow A sink source B sink sink C source source D source sink

1 marks

Answer: A

This question in 9700/12 Feb/March 2023

Q291 · What is the correct term to describe intermolecular hydrogen bonding between water… 9700/11 May/June 2023

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

1 marks

Answer: B

This question in 9700/11 May/June 2023

Q292 · The diagram shows the outline of a xerophytic leaf that had been left for 45 minutes in… 9700/11 May/June 2023

25 The diagram shows the outline of a xerophytic leaf that had been left for 45 minutes in different conditions, P and Q. Y Y P Q Which statements about the cells in layer Y of the leaf in each of the conditions P and Q after 45 minutes are correct? 1 There is a less negative water potential in P than in Q. 2 The cells may be turgid in P and plasmolysed in Q. 3 The cells are less turgid in P than in Q. 4 There is no net diffusion of water into Y in either P or Q. A 1, 2 and 4 B 1, 3 and 4 C 1 and 3 only D 2 and 4 only

1 marks

Answer: A

This question in 9700/11 May/June 2023

Q293 · How does sucrose move from chloroplasts to the phloem? 9700/11 May/June 2023

26 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

1 marks

Answer: A

This question in 9700/11 May/June 2023

Q294 · How are companion cells involved in loading sucrose into phloem sieve tube elements? 9700/11 May/June 2023

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

1 marks

Answer: A

This question in 9700/11 May/June 2023

Q295 · Which statements about the apoplast and symplast pathways are correct? 9700/12 May/June 2023

27 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 roots. 2 In the symplast pathway, water molecules diffuse through the cytoplasm and plasmodesmata of cells. 3 Water molecules travelling through plant tissue move by mass flow along the apoplast pathway. 4 The Casparian strip blocks the symplast pathway and forces all water molecules to enter the cytoplasm of endodermis cells. A 1, 2, 3 and 4 B 1, 2 and 3 only C 1 and 2 only D 3 and 4 only

1 marks

Answer: B

This question in 9700/12 May/June 2023

Q296 · Where does water evaporate from during transpiration? 9700/12 May/June 2023

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

1 marks

Answer: C

This question in 9700/12 May/June 2023

Q297 · The diagram shows the outline of three xerophytic leaves of the same type in three… 9700/12 May/June 2023

29 The diagram shows the outline of three xerophytic leaves of the same type in three different conditions, P, R and S. layer Y layer Y layer Y P R S Which description of the water potential of the cells in layer Y is correct? water potential of cells in layer Y P R S A higher than R and S lower than P and S lower than P B higher than S lower than P higher than P C lower than R higher than S higher than R D lower than R and S higher than P lower than P

1 marks

Answer: A

This question in 9700/12 May/June 2023

Q298 · Which statement supports the theory of active loading of sucrose into companion cells? 9700/12 May/June 2023

31 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 The pH decreases in the cytoplasm of the companion cells compared with the cell wall. C The pH decreases in the companion cells and sieve tube elements. D The pH decreases in the sieve tube elements compared with the companion cells.

1 marks

Answer: A

This question in 9700/12 May/June 2023

Q299 · Which row correctly explains how the structures of phloem sieve tube elements and xylem… 9700/13 May/June 2023

27 Which row correctly explains how the structures of phloem sieve tube elements and xylem vessel elements are related to their functions as transport systems? phloem sieve tube elements xylem vessel elements A contain mitochondria to make ATP cell walls are thickened and for the active loading of sucrose contain lignin which makes into the phloem xylem vessels waterproof B contain no nucleus so that end walls between cells are dissolved solutes can move easily perforated so that water can move through cells easily through xylem vessels C end walls between cells are lignin in cell walls gives strength so perforated so that dissolved solutes that xylem vessels do not collapse can move between cells due to transpiration pull D no end walls between cells so that contain no cytoplasm so that a sucrose solution can move up and continuous column of water can down the phloem move up the xylem vessels

1 marks

Answer: C

This question in 9700/13 May/June 2023

Q300 · Which component of plants is used by the apoplast pathway as water is moved from the soil… 9700/13 May/June 2023

28 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

1 marks

Answer: B

This question in 9700/13 May/June 2023

Q301 · Which statements correctly describe transport pathways in dicotyledonous plants? 9700/13 May/June 2023

29 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 be blocked by the tonoplast. 3 In the apoplast pathway, water does not move through plasmodesmata. 4 The apoplast pathway may be blocked by the Casparian strip. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

1 marks

Answer: D

This question in 9700/13 May/June 2023

Q302 · Which changes occur as sucrose is transferred from leaves into phloem sieve tubes to be… 9700/13 May/June 2023

31 Which changes occur as sucrose is transferred from leaves into phloem sieve tubes to be transported to a sink? water potential volume of liquid in phloem sieve in phloem tubes becomes sieve tubes A less negative decreases B less negative increases C more negative decreases D more negative increases

1 marks

Answer: D

This question in 9700/13 May/June 2023

Q303 · The graph shown does not have any axis labels 9700/13 May/June 2023

32 The graph shown does not have any axis labels. 0 0 Which row shows appropriate labels for the axes that would explain mass flow in phloem? x-axis y-axis A distance from sink / m hydrostatic pressure / kPa B hydrostatic pressure / kPa distance from sink / m C distance from source / m hydrostatic pressure / kPa D hydrostatic pressure / kPa distance from source / m

1 marks

Answer: C

This question in 9700/13 May/June 2023

Q304 · Four students sketched diagrams of the apoplast pathway and the symplast pathway 9700/12 Oct/Nov 2023

24 Four students sketched diagrams of the apoplast pathway and the symplast pathway. Which sketch is the most accurate diagram of the two pathways? Casparian strip symplast A xylem apoplast Casparian strip symplast B xylem apoplast Casparian strip apoplast C xylem symplast Casparian strip apoplast D xylem symplast

1 marks

Answer: D

This question in 9700/12 Oct/Nov 2023

Q305 · The photomicrograph shows some xerophytic adaptations in leaf tissue 9700/12 Oct/Nov 2023

25 The photomicrograph shows some xerophytic adaptations in leaf tissue. 1 2 3 Which row shows the correct functions for structures 1, 2 and 3? reduces the water vapour concentration reduces evaporation traps a layer of gradient between from the epidermis moist air the inside and outside of the leaf of the leaf A 1, 2 and 3 3 only 2 only B 1 and 2 only 1, 2 and 3 1 and 2 C 1 only 2 and 3 only 1 and 2 D 2 and 3 only 1 and 2 only 1 only

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2023

Q306 · Which processes are required for the transfer of assimilates from a source cell into a… 9700/12 Oct/Nov 2023

26 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 transport and exocytosis C active transport and simple diffusion only D active transport only

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2023

Q307 · When sucrose is loaded into the phloem it has to travel from mesophyll cells to a… 9700/12 Oct/Nov 2023

27 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 in each type of cell in order for this process to take place? relative concentration of sucrose / arbitrary units mesophyll companion phloem sieve cell cell tube element A 5 10 15 B 5 15 10 C 15 10 5 D 15 5 10

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2023

Q308 · Which feature of transport in plants is correct for xylem and phloem? 9700/12 Oct/Nov 2023

28 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.

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2023

Q309 · Hydrogen bonding explains many of the properties of water, including the high latent heat… 9700/13 Oct/Nov 2023

12 Hydrogen bonding explains many of the properties of water, including the high latent heat of vaporisation and high specific heat capacity. For which processes in plants is hydrogen bonding in water important on hot sunny days? 1 preventing denaturation of enzymes in leaves 2 reducing water loss by evaporation 3 allowing leaves to cool down quickly at night 4 holding the column of water in xylem vessels together A 1, 2, 3 and 4 B 1, 2 and 4 only C 1, 3 and 4 only D 2 and 3 only

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2023

Q310 · Ammonium ions, NH4 +, can enter the xylem of plant roots by two pathways 9700/13 Oct/Nov 2023

26 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 Casparian strip. Ammonium ions then enter the cytoplasm of root cells. ● In the symplast pathway, ammonium ions move through the cytoplasm of root cells. A scientist measured the uptake of ammonium ions into the xylem of Arabidopsis thaliana. The sgn3 mutant of A. thaliana does not have a Casparian strip. In the sgn3 mutant, ammonium ions can enter the xylem without entering the cytoplasm of root cells. The bar charts show the scientist’s results. low high concentration NH4 + concentration NH4 + 80 60 uptake of NH4 + into xylem 40 / μmol g–1 h–1 20 0 non- sgn3 non- sgn3 mutant mutant mutant mutant plant variety Which conclusion is correct? A Fewer ammonium ions enter the xylem when they have to move through the cytoplasm of root cells. B More ammonium ions enter the xylem at low soil concentrations of ammonium ions. C The Casparian strip acts as a barrier to reduce the movement of ammonium ions into the xylem. D The loss of the Casparian strip has little effect on the movement of ammonium ions into the xylem.

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2023

Q311 · Which row correctly shows processes required for the movement of water from a root hair… 9700/13 Oct/Nov 2023

27 Which row correctly shows processes required for the movement of water from a root hair cell to the atmosphere? cohesion diffusion evaporation Jv Jv Jv key v¥ = required 0 0O WwW > x v x v x Jv X = not required x v Jv

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2023

Q312 · A maize seedling was grown in soil that contained lanthanum ions labelled with a chemical… 9700/12 Feb/March 2024

29 A maize seedling was grown in soil that contained lanthanum ions labelled with a chemical that fluoresces under ultraviolet light. The diagram represents what was observed when a section of root was examined using a light microscope with ultraviolet illumination. key fluorescence root hair Casparian strip xylem What is a correct conclusion about the transport of lanthanum ions in maize roots? A The ions are not transported through the apoplast pathway or the symplast pathway. B The ions are transported through the apoplast pathway only. C The ions are transported through the apoplast pathway and symplast pathway. D The ions are transported through the symplast pathway only.

1 marks

Answer: B

This question in 9700/12 Feb/March 2024

Q313 · Which description of adhesion and cohesion is correct? 9700/12 Feb/March 2024

30 Which description of adhesion and cohesion is correct? A Adhesion refers to the force between the water molecules due to hydrogen bonding. Cohesion refers to the force between water molecules and the xylem vessel walls. B Adhesion refers to the reduced friction between hydrophobic lignin walls and the water molecules. Cohesion refers to the force between water molecules and the xylem vessel walls. C Adhesion refers to the reduced friction between hydrophobic lignin walls and the water molecules. Cohesion refers to the force between water molecules due to hydrogen bonding. D Adhesion refers to the force between the water molecules and the xylem vessel walls. Cohesion refers to the force between water molecules due to hydrogen bonding.

1 marks

Answer: D

This question in 9700/12 Feb/March 2024

Q314 · Which conditions are needed to allow the mass flow of sucrose in phloem sieve tubes? 9700/12 Feb/March 2024

31 Which conditions are needed to allow the mass flow of sucrose in phloem sieve tubes? phloem sieve tube in sources phloem sieve tube in sinks A higher hydrostatic pressure lower hydrostatic pressure higher water potential lower water potential B higher hydrostatic pressure lower hydrostatic pressure lower water potential higher water potential C lower hydrostatic pressure higher hydrostatic pressure higher water potential lower water potential D lower hydrostatic pressure higher hydrostatic pressure lower water potential higher water potential

1 marks

Answer: B

This question in 9700/12 Feb/March 2024

Q315 · The diagram shows how nicotine is transported from the blood plasma into a cell using a… 9700/11 May/June 2024

13 The diagram shows how nicotine is transported from the blood plasma into a cell using a type of cotransporter mechanism. protons move down their concentration gradient blood out of the cell plasma cell surface membrane cytoplasm of the cell nicotine is transported cotransporter protein against its concentration gradient into the cell In the phloem tissue, there is a cotransporter mechanism that moves sucrose into the cytoplasm of a companion cell. Which statement correctly describes a similarity between the cotransport of nicotine and the cotransport of sucrose? A The cotransporter proteins generate a proton gradient by moving protons out of the cell by active transport. B The protons are transported through the cotransporter proteins by facilitated diffusion. C The protons move through the cotransporter proteins in the opposite direction to the movement of nicotine and sucrose. D The cotransporter proteins use energy from ATP to transport protons with nicotine and sucrose.

1 marks

Answer: B

This question in 9700/11 May/June 2024

Q316 · Which row correctly identifies sinks for sucrose transported by mass flow in plants? 9700/12 May/June 2024

24 Which row correctly identifies sinks for sucrose transported by mass flow in plants? root storage growing growing organ leaf bud shoot tip A v Jv J key B v x v v= sink Cc x v x X = not a sink D x x J

1 marks

Answer: A

This question in 9700/12 May/June 2024

Q317 · Which statement correctly describes the movement of solutes in the symplast pathway? 9700/12 May/June 2024

26 Which statement correctly describes the movement of solutes in the symplast pathway? A Cell surface membranes regulate the selective absorption of solutes into the symplast pathway. B Plasmodesmata control the movement of solutes from the symplast pathway to the apoplast pathway. C The symplast pathway transports dissolved mineral ions from the soil that cannot be transported by the apoplast pathway. D The movement of solutes through plasmodesmata in the symplast pathway is prevented in the endodermis by suberin.

1 marks

Answer: A

This question in 9700/12 May/June 2024

Q318 · Which statement helps to explain why water molecules are forced to move through xylem… 9700/12 May/June 2024

27 Which statement helps to explain why water molecules are forced to move through xylem vessel elements as a consequence of transpiration? A Water molecules form hydrogen bonds with cellulose in the walls of xylem vessel elements in a process known as adhesion. B Water molecules form hydrogen bonds with neighbouring water molecules in a process known as cohesion. C Water molecules form ionic bonds with dissolved mineral ions, which helps to keep the water molecules together in a continuous column. D Water has a high latent heat of vaporisation and this prevents the evaporation of water in the xylem vessel elements.

1 marks

Answer: B

This question in 9700/12 May/June 2024

Q319 · Carrier proteins in the cell surface membranes of companion cells are involved in the… 9700/13 May/June 2024

28 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 carrier protein in this process. key X X X X Y X X pump X Y companion X X cell cytoplasm cotransporter cell surface membrane What are the substances labelled X and Y? X Y A H+ ions sucrose B H+ ions glucose C sucrose H+ ions D glucose H+ ions

1 marks

Answer: A

This question in 9700/13 May/June 2024

Q320 · Which statement correctly identifies the movement of sucrose and amino acids in plant… 9700/11 Oct/Nov 2024

27 Which statement correctly identifies the movement of sucrose and amino acids in plant vascular tissue? A They are carried from source to sink by mass flow in upward and downward directions. B They are carried from sink to source by cohesion-tension in upward and downward directions. C They are carried from sink to source by mass flow in one direction. D They are carried from source to sink by cohesion-tension in one direction.

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2024

Q321 · The diagram shows a longitudinal section of a phloem sieve tube with a companion cell 9700/12 Oct/Nov 2024

26 The diagram shows a longitudinal section of a phloem sieve tube with a companion cell. Where are the mitochondria located for the release of energy for cotransport? A B C D

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2024

Q322 · The diagram shows a phloem sieve tube element and a companion cell that are involved in… 9700/12 Oct/Nov 2024

27 The diagram shows a phloem sieve tube element and a companion cell that are involved in translocation of sucrose. W X Y Z Which process correctly describes the translocation of sucrose through these cells? A Sucrose moves from Y to Z by active transport. B Protons move from Y to Z by active transport. C Protons move from Z to Y by diffusion. D Protons move from X to W by diffusion.

1 marks

Answer: B

This question in 9700/12 Oct/Nov 2024

Q323 · Which types of molecules are cotransported into companion cells? 9700/12 Oct/Nov 2024

28 Which types of molecules are cotransported into companion cells? A monomers and disaccharides B monomers and polysaccharides C polymers and disaccharides D polymers and monosaccharides

1 marks

Answer: A

This question in 9700/12 Oct/Nov 2024

Q324 · The diagram shows some structures used for transport in the phloem 9700/13 Oct/Nov 2024

28 The diagram shows some structures used for transport in the phloem. cell Y companion cell Z cell direction of phloem sieve tube transport long distance Which statement is correct? A Cell Y is the sink cell. B Cell Z can be above or below cell Y in the plant. C Cell Z must be in a photosynthetic tissue. D Cell Y allows glucose to move to the sieve tube via the companion cell.

1 marks

Answer: B

This question in 9700/13 Oct/Nov 2024

Q325 · The diagram shows a section through a root of a dicotyledonous plant 9700/13 Oct/Nov 2024

29 The diagram shows a section through a root of a dicotyledonous plant. soil particle root hair root cell xylem cell vessel Casparian strip Which statement correctly describes the movement of water and solutes through this root? A A layer of suberin causes water and solutes to move from the apoplast pathway into the symplast pathway. B A layer of suberin causes water and solutes to move from the symplast pathway into the apoplast pathway. C The tonoplast causes water and solutes to move from the symplast pathway into the apoplast pathway. D The tonoplast causes water and solutes to move from the apoplast pathway into the symplast pathway.

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2024

Q326 · Which row correctly describes the role of growing leaves as sources or sinks for amino… 9700/12 Feb/March 2025

26 Which row correctly describes the role of growing leaves as sources or sinks for amino acids and sucrose? amino acids sucrose A leaves act as leaves can act as sinks only sources or sinks B leaves act as leaves act as sinks only sources only C leaves can act as leaves act as sources or sinks sources only D leaves can act as leaves can act as sources or sinks sources or sinks

1 marks

Answer: D

This question in 9700/12 Feb/March 2025

Q327 · Which changes occur as amino acids are moved into phloem sieve tubes at a source? 9700/12 Feb/March 2025

28 Which changes occur as amino acids are moved into phloem sieve tubes at a source? change in change in water potential in volume of sap in phloem sieve tubes phloem sieve tubes A decreases decreases B decreases increases C increases decreases D increases increases

1 marks

Answer: B

This question in 9700/12 Feb/March 2025

Q328 · Which row is correct for transpiration? 9700/12 May/June 2025

26 Which row is correct for transpiration? definition of transpiration comparison of water potential A evaporation of water higher inside air spaces in from leaf surfaces the leaf than the air outside B evaporation of water lower inside air spaces in from leaf surfaces the leaf than the air outside C loss of water vapour lower inside air spaces in from leaves the leaf than the air outside D loss of water vapour higher inside air spaces in from leaves the leaf than the air outside

1 marks

Answer: D

This question in 9700/12 May/June 2025

Q329 · The diagram shows some root cells 9700/12 May/June 2025

28 The diagram shows some root cells. cell wall vacuole cytoplasm key pathway of water moving from the soil Which statement is correct for the pathway shown by the arrows? A Water will be blocked by a band of suberin. B Water will move through the Casparian strip. C Water will pass easily through the root endodermis. D Water will pass through plasmodesmata.

1 marks

Answer: A

This question in 9700/12 May/June 2025

Q330 · The graph shows the diameter of a tree trunk at different times 9700/12 May/June 2025

29 The graph shows the diameter of a tree trunk at different times. J L diameter of tree trunk K / arbitrary units 00:00 12:00 00:00 time of day Which statement is correct? A J shows the expansion of the trunk as water fills the xylem during transpiration. B K shows a reduction in diameter of the trunk as water is lost from the phloem due to translocation. C K shows a reduction in diameter of the trunk due to water held in tension in the xylem. D L shows the expansion of the trunk as the phloem tissue acts as a sink at night.

1 marks

Answer: C

This question in 9700/12 May/June 2025

Q331 · The plan diagrams of transverse sections of two plant organs are shown 9700/12 May/June 2025

30 The plan diagrams of transverse sections of two plant organs are shown. These are not drawn to scale. S Q T R Which tissues contain proton pumps? A Q and S B Q and T C R and S D R and T

1 marks

Answer: C

This question in 9700/12 May/June 2025

Q332 · The diagram shows a bond between two molecules transported in a xylem vessel 9700/13 May/June 2025

28 The diagram shows a bond between two molecules transported in a xylem vessel. δ– O bond R δ+ δ+ H H δ– O δ+ δ+ H H Which row correctly names bond R and states the role of the bond between these molecules for their transport in a xylem vessel? role of the bond between name of bond R these molecules for their transport in a xylem vessel A hydrogen adhesion of the molecules to the wall of the xylem vessel B hydrogen cohesion of the molecules in the lumen of the xylem vessel C ionic adhesion of the molecules to the wall of the xylem vessel D ionic cohesion of the molecules in the lumen of the xylem vessel

1 marks

Answer: B

This question in 9700/13 May/June 2025

Q333 · How can water and solutes move through a leaf? 9700/13 May/June 2025

29 How can water and solutes move through a leaf? A through the lignified endodermis using the apoplast pathway B through the cytoplasm of cells using the symplast pathway C through the cell walls containing cellulose by osmosis D through the cell walls containing suberin by diffusion

1 marks

Answer: B

This question in 9700/13 May/June 2025

Q334 · Two plants, K and L, are parasites of other plants 9700/14 May/June 2025

27 Two plants, K and L, are parasites of other plants. Both species grow structures that invade the vascular tissue of plants. Plant K grows into xylem tissue of other plants. Plant L grows into phloem tissue of other plants. Which substances could plants K and L take from the plants that they parasitise? plant K plant L A water only water and sucrose only B water and minerals water, amino acids and sucrose C water only amino acids and sucrose only D water and minerals water and sucrose only

1 marks

Answer: B

This question in 9700/14 May/June 2025

Q335 · Which statements are correct for the apoplast pathway? 9700/14 May/June 2025

28 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 plasmodesmata. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

1 marks

Answer: B

This question in 9700/14 May/June 2025

Q336 · Mass flow is the bulk movement of materials from one place to another 9700/14 May/June 2025

29 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 A 1, 2, 3 and 4 B 1, 2 and 3 only C 1 and 3 only D 2 and 4 only

1 marks

Answer: A

This question in 9700/14 May/June 2025

Q337 · What causes water to move from the root hair cells to the endodermis? 9700/11 Oct/Nov 2025

28 What causes water to move from the root hair cells to the endodermis? A diffusion through cell walls and osmosis down a water potential gradient in the cytoplasm B diffusion through the symplast and osmosis and root pressure through the apoplast C osmosis from cell vacuole to cell vacuole and active transport into the endodermis D osmosis through the intercellular spaces and diffusion in cell walls and cytoplasm

1 marks

Answer: A

This question in 9700/11 Oct/Nov 2025

Q338 · Which changes occur as carbohydrate is moved into a sink? 9700/11 Oct/Nov 2025

29 Which changes occur as carbohydrate is moved into a sink? water potential volume of liquid of the sieve tube of the sieve element becomes tube element A lower decreases B lower increases C higher decreases D higher increases

1 marks

Answer: C

This question in 9700/11 Oct/Nov 2025

Q339 · Which statement about the pathway taken by a water molecule travelling from the soil to… 9700/13 Oct/Nov 2025

29 Which statement about the pathway taken by a water molecule travelling from the soil to the xylem is correct? A A water molecule in a cortex cell that takes the symplast pathway must enter the next cortex cell by passing between two adjacent phospholipid molecules in a cell surface membrane. B A water molecule can pass into xylem vessels either through pits or through the cell wall of the xylem vessel elements by osmosis. C A water molecule would pass into the cytoplasm of the endodermal cell if it always takes the apoplast pathway all the way to the xylem. D A water molecule that has left the endodermal cells can travel by either the apoplast pathway or symplast pathway.

1 marks

Answer: D

This question in 9700/13 Oct/Nov 2025

Q340 · Amino acids move from a phloem sieve tube element into a root cell 9700/13 Oct/Nov 2025

30 Amino acids move from a phloem sieve tube element into a root cell. What are the changes to the water potential and the volume of liquid in the phloem sieve tube element at the sink, when this event is happening? water potential in volume of liquid in the phloem sieve the phloem sieve tube element tube element A becomes higher decreases B becomes higher increases C becomes lower decreases D becomes lower increases

1 marks

Answer: A

This question in 9700/13 Oct/Nov 2025