(a) You will investigate the effect of different temperatures on the permeability of the cell surface membrane of beetroot cells. Beetroot is a vegetable that contains a red pigment in its cells. When beetroot tissue is put into water, the red pigment can move out of the cells through the cell surface membrane, changing the water to a red colour. You are provided with the materials shown in Table 1.1. Table 1.1 labelled | contents | hazard | volume/cm³ --- | --- | --- | --- B | 2 pieces of beetroot | none | – W | distilled water | none | 100 The red pigment in beetroot cells can stain clothing and skin. Use blunt forceps to handle beetroot tissue and, if any pigment comes into contact with your skin, wash it off immediately under cold water. It is recommended that you wear suitable eye protection. You will need to: • put beetroot tissue in water at different temperatures • leave the beetroot tissue in the water for a period of time • record the intensity of colour in the water at each temperature. (b) A scientist investigated changes in the mean width of stomata in the leaves of a plant growing in hot, dry conditions. The scientist measured the widths of stomata at different times of day, from 02:00 hours to 22:00 hours. [Figure 1.1] shows where the scientist measured the width of each stoma. width of stoma [Figure 1.1] guard cell The scientist calculated the mean width of stomata for each time of day. The results are shown in Table 1.4. Table 1.4 time of day /hours | mean width of stomata /arbitrary units (au) --- | --- 02:00 | 86 04:00 | 36 07:00 | 4 15:00 | 2 22:00 | 95