R ‘move bubble to end’ ideas 11 start timing and, measure / calculate, distance moved per unit time / AW; max 3 [8] (i) 103; 1 53. R decimals (ii) plant A around stoma; trap, moisture / water vapour; reduces the water potential gradient; so transpiration rate is reduced; max 3 [4] 54. 1 (water moves) by osmosis; 2 down water potential gradient/from high to low Ψ Ψ; (less negative to more negative) 3 sea water has low water potential/(soil) water potential decreased; (more negative) gradient reduced/lower than inside, root/cells/plant; 4 Ψ, 5 plant, loses/can’t absorb (as much), water; 6 cells, flaccid/lose turgor; 7 plasmolysis/described; 8 wilting/poor growth; in correct context 4 max Credit suitable equivalent marking points if they state that internal and external ψ are equal [4] 55. (i) fluid mosaic; A 1 Singer-Nicholson (ii) phospholipid; A A R bilayer B cholesterol; A (free) acids/fat-soluble vitamins C glycolipid; D carbohydrate; A 4 glycoprotein/glucose residue/glycocalyx [5] 56. at surface S1 separate cell from environment; S2 control, entry/exit (of molecules/ions/suitable substance); A R selective/partial semi-permeable S3 use of phospholipid layer (in allowing or preventing passage) of suitable example;
R ‘move bubble to end’ ideas 11 start timing and, measure / calculate, distance moved per unit time / AW; max 3 [8] 53. (i) 103; R decimals 1 (ii) plant A around stoma; trap, moisture / water vapour; reduces the water potential gradient; so transpiration rate is reduced; max 3 [4] 54. 1 (water moves) by osmosis; 2 down water potential gradient/from high Ψ to low Ψ; (less negative to more negative) 3 sea water has low water potential/(soil) water potential decreased; (more negative) 4 Ψ, gradient reduced/lower than inside, root/cells/plant; 5 plant, loses/can’t absorb (as much), water; 6 cells, flaccid/lose turgor; 7 plasmolysis/described; 8 wilting/poor growth; in correct context 4 max Credit suitable equivalent marking points if they state that internal and external ψ are equal [4] 55. (i) fluid mosaic; A Singer-Nicholson 1 (ii) A phospholipid; A R bilayer B cholesterol; A (free) acids/fat-soluble vitamins C glycolipid; D carbohydrate; A glycoprotein/glucose residue/glycocalyx 4 [5] 56. at surface S1 separate cell from environment; S2 control, entry/exit (of molecules/ions/suitable substance); A selective/partial R semi-permeable S3 use of phospholipid layer (in allowing or preventing passage) of suitable example;