Biology 9700/35 May June 2015 | Cambridge AS Level Past Papers With Mark Scheme

1. Enzyme-catalyzed reactions involving urea hydrolysis; preparation of serial dilutions and observation of end-point using litmus paper for pH indication.

2. Analysis of experimental errors and improvements; systematic errors in apparatus and procedural modifications to enhance timing accuracy for short reactions.

3. Urea breath test for detecting stomach infections; isotope labeling with 13C in urea and trends in enzyme activity over time in breath analysis.

4. Plan and detailed cell drawings of plant stem transverse sections; identification and comparison of epidermal and cortical cells based on linear magnification.

5. Calibration of eyepiece graticules in light microscopy; unit conversions and measurement of tissue dimensions in photomicrographs.

6. Feature-based assessment of plants adapted to freshwater pond environments; observable structural traits supporting habitat suitability.

7. Comparative analysis of plant stem specimens from different environments; recording morphological differences in a structured format.