Transport in plantsIB MYP Biology: Flashcards

Exam questions on Transport in plants

1. A student in a school in Kenya stands a white carnation in a beaker of water containing red food dye. After one day, red streaks have appeared along the stem and in the petals of the flower.
   Explain how the structure of xylem vessels makes them well adapted to carry water up a tall stem.2 marks
2. A forester removes a complete ring of bark, including the phloem, from around the trunk of a young tree. Over the following months the trunk swells just above the ring, and the roots below the ring slowly die, although the leaves stay green for some time.
   Explain why the roots below the ring slowly die.2 marks
3. A student uses a potometer, which measures how much water a cut leafy shoot takes up, to investigate the effect of wind on transpiration. She uses shoots of the same plant species with similar numbers of leaves. She places an electric fan 50 cm, 100 cm and 150 cm from the shoot and records how far an air bubble moves along the capillary tube in 10 minutes. She repeats each distance three times in a room at 22 °C. The mean bubble movement is 42 mm with the fan at 50 cm, 30 mm at 100 cm and 21 mm at 150 cm.
   Identify the independent variable, the dependent variable and one control variable in this investigation.3 marks