ignore / gradient ‘along’ ‘across’ ignore gradient ‘with’ 1 (ii) oxygen / water (vapour) allow O2 / O2 ignore O2/ O allow H2O / H2O ignore H2O 1 [4] M6.(a) (i) guard (cells) allow phonetic spelling 1 (ii) any one from: ignore reference to cells allow carbon dioxide to enter • allow control loss / evaporation of water or control transpiration rate allow oxygen to leave. • allow exchange’ ‘gaseous 1 (b) (i) 200 correct answer gains 2 marks with or without working allow 1 mark for 0.1 × 0.1 = 0.01 (mm2) 2 (ii) more / a lot of / increased water loss allow plant more likely to wilt (in hot / dry conditions) 1 (c) (i) 0.12 1
ignore ‘along’ / ‘across’ gradient ignore ‘with’ gradient 1 (ii) oxygen / water (vapour) allow O2 / O2 ignore O2/ O allow H2O / H2O ignore H2O 1 [4] M6.(a) (i) guard (cells) allow phonetic spelling 1 (ii) any one from: ignore reference to cells • allow carbon dioxide to enter allow control loss / evaporation of water or control transpiration rate • allow oxygen to leave. allow ‘gaseous exchange’ 1 (b) (i) 200 correct answer gains 2 marks with or without working allow 1 mark for 0.1 × 0.1 = 0.01 (mm2) 2 (ii) more / a lot of / increased water loss allow plant more likely to wilt (in hot / dry conditions) 1 (c) (i) 0.12 1
b4_organisation_in_plants_mark_scheme.docx