Biology 9700/35 Oct Nov 2010 | Cambridge AS Level Past Papers With Mark Scheme

1. Determination of ascorbic acid concentration in samples using iodine titration until a stable blue endpoint is reached.
2. Preparation of serial dilutions for a range of ascorbic acid concentrations, including calculations and recording of results.
3. Graphical representation of ascorbic acid concentration data and interpolation to estimate unknown sample concentrations.
4. Identification of significant experimental errors in iodine titration methods and suggestions for investigation improvements.
5. Plan diagrams and vascular bundle analysis in leaf transverse sections, emphasizing chloroplast-containing tissues and phloem labeling.
6. Comparative analysis of leaf sections for xerophytic adaptations, including tissue thickness ratios and structural differences.