Mature xylem vessels have hollow centres and walls containing lignin.
Which statement explains the function of the lignin?
It controls the entry of sucrose through the membrane.
It strengthens the vessels and helps prevent collapse.
It allows the vessels to absorb light for photosynthesis.
It releases the energy needed to pump water upwards.
43 exam-style questions on Edexcel GCSE Biology 6.2 Transport in plants, covering 6.2.1 Root hair cell adaptations, 6.2.2 Structure of xylem and phloem, 6.2.3 Transpiration and stomata, 6.2.4 Translocation of sucrose, 6.2.5 Leaf structure for photosynthesis, 6.2.6 Environmental factors on water uptake, 6.2.7 Rate calculations for transpiration, and 6.2.8 Plant adaptations to extreme environments. Each one has a worked solution and a mark scheme showing where the marks go.