Biology 9700/53 Oct Nov 2023 | Cambridge AS Level Past Papers With Mark Scheme

1. Investigation of ascorbic acid concentration changes in apples during ripening using DCPIP as a redox indicator.

2. Two-step dilution method to prepare 0.0005 mol dm⁻³ DCPIP solution from a 0.01 mol dm⁻³ stock solution for accurate titration.

3. Application of Pearson’s linear correlation to evaluate the relationship between ripeness and ascorbic acid concentration.

4. Analysis of β-carotene content in apples compared to other fruits, utilizing standard deviation error bars for data reliability.

5. Comparison of trypsin activity from Atlantic salmon and domestic pigs in gelatin digestion at a standardized temperature of 20°C.

6. Statistical analysis using t-test to determine significant differences in enzyme activity, with explanations for observed variations based on physiological adaptations of ectothermic and endothermic species.