A student uses a potometer to measure the rate of water uptake of a leafy shoot. This water is required to supply the leaf cells and replace water lost via transpiration. The capillary tube of the potometer has an internal diameter of 1.0 mm. Under specific environmental conditions, the bubble in the capillary tube moves a distance of 80 mm in 15 minutes15\text{ minutes}15 minutes. The total surface area of the leaves on the shoot is 25 cm2.
Calculate the rate of water uptake by this shoot per unit area of leaf, in mm3 cm−2 min−1\text{mm}^3\text{ cm}^{-2}\text{ min}^{-1}mm3 cm−2 min−1 to 3 significant figures.
0.670 mm3 cm−2 min−10.670\text{ mm}^3\text{ cm}^{-2}\text{ min}^{-1}0.670 mm3 cm−2 min−1
0.168 mm3 cm−2 min−10.168\text{ mm}^3\text{ cm}^{-2}\text{ min}^{-1}0.168 mm3 cm−2 min−1
2.51 mm3 cm−2 min−12.51\text{ mm}^3\text{ cm}^{-2}\text{ min}^{-1}2.51 mm3 cm−2 min−1
4.19 mm3 cm−2 min−14.19\text{ mm}^3\text{ cm}^{-2}\text{ min}^{-1}4.19 mm3 cm−2 min−1
82 exam-style questions on OCR GCSE Biology 2.1 Supplying the cell, covering 2.1.1 Transport across cell membranes, 2.1.2 Mitosis and the cell cycle, 2.1.3 Importance of cell differentiation, and 2.1.4 Stem cells. Each one has a worked solution and a mark scheme showing where the marks go.