CIE iGCSE Co-Ordinated Science B8.2 Water uptake Exam Style Questions Paper 1
▶️ Answer/Explanation
When water evaporates from leaf cells, the cells lose water and become more concentrated (lower water potential). Water then moves into these cells from adjacent cells and ultimately from the xylem by osmosis — the net movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane. Assimilation is the uptake and use of nutrients by cells, egestion is the removal of undigested food, and transpiration is the loss of water vapour itself, not the process that replaces it.
✅ Answer: (C)
✅ Answer: (C)
▶️ Answer/Explanation
In a cross-section of a plant stem, the vascular bundles are arranged in a ring.
The xylem is typically found on the inner side of the vascular bundle (towards the centre of the stem), while the phloem is on the outer side.
X is pointing to the inner tissue, which is the xylem.
✅ Answer: (D)
The xylem is typically found on the inner side of the vascular bundle (towards the centre of the stem), while the phloem is on the outer side.
X is pointing to the inner tissue, which is the xylem.
✅ Answer: (D)
▶️ Answer/Explanation
Root hair cells are specialised for absorption. They have a large central vacuole that pushes the cytoplasm into a thin layer against the cell wall, so compared to other cells they have less cytoplasm. Their elongated shape greatly increases surface area for water and mineral ion uptake.
✅ Answer: (A)
✅ Answer: (A)
▶️ Answer/Explanation
Root hairs are specialised cells that greatly increase the surface area for absorption of water and mineral ions from the soil. They do not photosynthesise (no chloroplasts), they do not provide support, and water transport to leaves is the function of xylem, not root hairs directly.
✅ Answer: (A)
✅ Answer: (A)