AQA_A Level Biology Paper 1_Mark Scheme 2022 | Practice Paper 1

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AQA A Level Biology Paper 1 Mark Scheme 2022 Practice Paper 1 - - - - 1 (a) (i) fructose; 1 (ii) correctly drawn (OH group at bottom left); 1 (b) hydrolysis; 1 (c) (i) heat with Benedict’... s solution (disqualify if HCl added); orange / brown / brick red / green / yellow colour or precipitate; 2 (ii) biuret test / NaOH + CuSO4; purple / violet / lilac / mauve; 2 (d) Starch (max 3) 1. Context of storage for starch, structure for cellulose 2. Helical/ spiral shape so compact; 3. Large (molecule)/insoluble so osmotically inactive; Accept: does not affect water potential/ψ. 4. Branched so glucose is (easily) released for respiration; Ignore: unbranched. 5. Large (molecule) so cannot leave cell/cross cell-surface membrane; Cellulose (max 3) 5. Long, straight/unbranched chains of β glucose; 6. Joined by hydrogen bonding; Note: references to ‘strong hydrogen bonds’ disqualifies this mark point. 7. To form (micro/macro)fibrils; 8. Provides rigidity/strength; - - - AQA A Level Biology Paper 1 Mark Scheme 2022 Practice Paper 1 - - - - 1 (a) (i) fructose; 1 (ii) correctly drawn (OH group at bottom left); 1 (b) hydrolysis; 1 (c) (i) heat with Benedict’s solution (disqualify if HCl added); orange / brown / brick red / green / yellow colour or precipitate; 2 (ii) biuret test / NaOH + CuSO4; purple / violet / lilac / mauve; 2 (d) Starch (max 3) 1. Context of storage for starch, structure for cellulose 2. Helical/ spiral shape so compact; 3. Large (molecule)/insoluble so osmotically inactive; Accept: does not affect water potential/ψ. 4. Branched so glucose is (easily) released for respiration; Ignore: unbranched. 5. Large (molecule) so cannot leave cell/cross cell-surface membrane; Cellulose (max 3) 5. Long, straight/unbranched chains of β glucose; 6. Joined by hydrogen bonding; Note: references to ‘strong hydrogen bonds’ disqualifies this mark point. 7. To form (micro/macro)fibrils; 8. Provides rigidity/strength; - - - [Show More]

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