Biology 9700/31 May June 2008 | Cambridge AS Level Past Papers With Mark Scheme

1. Identification of glucose, protein, and carbohydrate solutions using biochemical tests, and estimation of glucose concentration with qualitative color changes.
2. Errors in estimating glucose concentration due to subjective color judgment and solution inconsistencies, and strategies to improve accuracy by using spectrophotometry or standardized color charts.
3. Analysis of starch concentration via light transmission using a colorimeter, with calculations for anomalous results and graphical plotting of transmission against concentration.
4. Xerophytic leaf adaptations for arid environments, including structural features like trichomes and stomatal positioning.
5. Measurement of trichome dimensions using eyepiece graticules and stage micrometers, highlighting potential errors in alignment or focus during microscopy.
6. High-power drawings and comparative analysis of leaf cross-sections to identify structural differences in xerophytes, including thickness of layers and protective adaptations.