AQA GCSE BIOLOGY 8461/1H Paper 1 Higher Tier Mark scheme June 2022 Version: 1.0 Final Mark Scheme

Similarities: both have: • cytoplasm • cell membrane • pigments (although they are different) ignore references to mitochondria and ribosomes for Level 2, consideration of both red blood cells and plant cells is required. 01.6 water enters (the cells) by allow water enters and the cell 1 AO2 osmosis / diffusion starts to swell ignore explanations of osmosis plant cell has a cell wall (which allow red blood cell has no cell 1 AO1 prevents it from bursting) wall (so it swells and bursts) 4.1.3.2 4.1.1.2 Total 13 Question Answers Extra information Mark AO / Spec. Ref. 02.1 any two from: • sterilise equipment / surfaces (before use) • (use) sterilised agar ignore ‘clean’ unqualified ignore wash hands allow description of how to sterilise equipment allow description of how to sterilise agar 2 AO1 4.1.1.6 RPA2 • secure lid of the Petri dish with (adhesive) tape • only lift lid of Petri dish a little (when setting up plate) or lift lid of Petri dish at an angle (when setting up plate) 02.2 B and it kills the fewest bacteria or it has the smallest area where no bacteria were growing allow it has the smallest clear / white area 1 AO3 4.1.1.6 RPA2 02.3 an incorrect answer for one step AO2 does not prevent allocation of 4.1.1.6 marks for subsequent steps RPA 2 ignore calculation and subtraction of filter paper disc area from total area (correct measurement) 1 r = 1.1 (cm) allow d = 2.2 (cm) or or r = 11 (mm) d = 22 (mm) allow a tolerance of ±1 mm (recall of the equation) 1