CAIE A Level Biology 9700 · Transport in plants
In a herbaceous dicotyledonous plant, water is transported from roots to leaves under tension created by transpiration. The xylem vessel elements are highly specialised cells. Using your knowledge of the structure of xylem vessel elements, explain how their adaptations enable efficient and safe transport of water and mineral ions under tension.
6 marks, so the mark scheme is looking for about 6 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.