9700 · 7.1
Structure of transport tissues — FAQ
Frequently asked questions for 9700 Structure of transport tissues. Direct answers first, then deeper explanation — then practise with marking.
What is the main difference between xylem and phloem structure in Biology 9700?
Xylem vessels are composed of dead, lignified cells forming hollow tubes for water and mineral transport, providing structural support. Phloem consists of living sieve tube elements and metabolically active companion cells, specialised for transporting sugars. For more details and practice questions, check out our free Cambridge 9700 Biology course and past papers.
How do xylem vessels adapt to their function in water transport for Cambridge Biology?
Xylem vessels are adapted with lignified walls for strength against negative pressure, they are hollow and continuous for efficient flow, and their narrow lumen aids capillary action. These features are key for efficient water and mineral transport. You can find more structured explanations and worked examples in our premium revision lessons.
What is the role of companion cells in phloem tissue according to the 9700 syllabus?
Companion cells are essential for phloem function. They are metabolically active, containing a nucleus, dense cytoplasm, and numerous mitochondria, supplying ATP and performing metabolic functions for the sieve tube elements. They actively load and unload sucrose into/out of the sieve tubes. Master these concepts with our comprehensive revision notes and past papers available on the platform.