Biology 9700/33 May June 2011 | Cambridge AS Level Past Papers With Mark Scheme

1. Serial dilution method to prepare enzyme concentration gradients for urease-catalyzed ammonium carbonate formation experiments.
2. Use of litmus paper to monitor pH changes as a reaction indicator and calculate reaction rates.
3. Charting nitrogen fixation sources, including industrial, agricultural, depositional, and natural methods, with historical comparisons of fixation rates.
4. Drawing and analysis of leaf structures in xerophytic plants, highlighting adaptations like trichomes and thick cuticles for reducing water loss.
5. Measurement of structures in photomicrographs using magnification to calculate actual dimensions in micrometers.
6. Comparison of leaf specimens across different species to identify structural similarities and differences, focusing on environmental adaptations.