Biology 9700/03 Oct Nov 2003 | Cambridge AS Level Past Papers With Mark Scheme

1. Reducing sugar investigation: Benedict’s test on extracts from tomato, grapes, and grapefruit; preparation of glucose standards (0.5% and 0.25%) for comparison.

2. Glucose solution preparation: serial dilution techniques for consistent concentration gradients, ensuring reliable reference points in Benedict's test.

3. Accuracy in Benedict’s tests: maintaining consistent heating times, reagent volumes, and conditions across all test tubes to ensure valid comparisons.

4. Interpretation of results: relative reducing sugar concentrations in fruits inferred from color intensity changes compared to glucose standards.

5. Dicotyledon leaf analysis: low-power plan diagram illustrating tissue distribution, highlighting vascular bundles, epidermis, and mesophyll layers.

6. Cellular comparison: structural differences between palisade mesophyll cells beneath the upper epidermis and spongy mesophyll cells above the lower epidermis, including cell shape and chloroplast density.