8. Transport in plants
A section of Biology, 0610
Listing 10 of 511 questions
shows part of a cross-section of the stem of a young sunflower plant. area Y Draw a circle around one vascular bundle on . Label the xylem in the vascular bundle with the letter X. Explain how the cells in area Y are able to support the stem so that it stays upright. Researchers used carbon dioxide that contained a traceable source of carbon (13C) to investigate translocation of sucrose from the leaves of bean plants, Phaseolus vulgaris. shows that glucose produced in photosynthesis is converted to sucrose for translocation. carbon dioxide glucose sucrose Researchers selected four plants, Q, R, S and T, which had leaves that were of similar sizes. The leaves on the four plants were supplied with 13CO2. After the leaves had started to make sucrose, the researchers cut away a ring of tissue in different places as shown in . The rings of tissue that were removed from plants R, S and T contained the phloem. 13CO2 13CO2 13CO2 13CO2 Q R S T Key: the positions on the stems where rings of tissue containing phloem were removed.
0610_w19_qp_42
THEORY
2019
Paper 4, Variant 2
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Plants produce glucose in leaves and convert some of it to sucrose. Explain how glucose is produced in leaves. State the name of the process that plants use to move sucrose from a source to a sink. Roots can be an example of a sink. Explain why sometimes roots act as a source rather than a sink. The movement of sucrose in plants can be modelled using laboratory apparatus. shows the apparatus used to model the movement of sucrose in a plant: • Partially permeable bags were attached tightly to the ends of tube Q. • The bag representing a source was filled with a coloured sucrose solution. • The bag representing a sink was filled with water. • The containers and tube Q and tube S were filled with water. bag representing a source containing a coloured sucrose solution partially permeable membrane P water tube Q bag representing a sink containing water partially permeable membrane R tube S shows the position of the coloured sucrose solution 30 minutes after the apparatus was set up. The arrows show the direction of the movement of the liquids. bag representing a source partially permeable membrane P water tube Q movement of sucrose solution movement of water bag representing a sink partially permeable membrane R tube S State the name of the tissue represented by tube Q and the name of the tissue represented by tube S in . Q S Explain why the sucrose solution moves along tube Q in the model in . In plants the movement of sucrose is usually continuous. However, after 2 hours the movement of sucrose in tube Q in stopped. Suggest why the movement of sucrose in tube Q stopped. Amino acids are also transported through plants. State the name of the mineral ion that is used to make amino acids.
0610_w19_qp_43
THEORY
2019
Paper 4, Variant 3
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Aphids are arthropods. Aphids insert their mouthpieces into the phloem in the stem of a plant to feed. An aphid is shown in . magnification ×22 Identify two features visible in that can be used to classify an aphid as an insect. is a diagram of a cross-section of a dicotyledonous stem. J L M N State the letter in that identifies the structure from which aphids feed. State the names of two nutrients transported in the phloem. Scientists investigated the effect of temperature on the rate of translocation. The data are shown in Table 2.1. Table 2.1 temperature / °C rate of translocation / cm per hour 7.3 13.8 16.7 17.1 Calculate the percentage change in rate of translocation between 15 °C and 30 °C. Give your answer to three significant figures. Space for working. % shows a potato plant growing in the spring and then in the summer. summer spring growing shoot potato tuber Explain how translocation changes between spring and summer in the potato plant shown in . Use the terms source and sink in your answer. New tubers form on the potato plant in the summer. These tubers are genetically identical. Identify the type of reproduction that the potato plant is using to form the tubers.
0610_w24_qp_43
THEORY
2024
Paper 4, Variant 3
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Questions Discovered
511