Biology 9700/34 May June 2013 | Cambridge AS Level Past Papers With Mark Scheme

1. Investigation of yeast respiration: rate of carbon dioxide release over time, standardized color endpoint detection using indicator P, and apparatus setup.

2. Collection and processing of raw data to observe trends in time to endpoint for CO\\(_2\\) release, calculation of differences between first and second sets of readings.

3. Identification of errors in experimental setup, including inconsistent mixing, tubing position, and endpoint color judgment.

4. Modifications to improve data reliability: precise tubing standardization, repeated measurements, and use of automated endpoint detection.

5. Plant leaf section analysis: plan diagrams, vascular bundle measurements, and ratio of vascular diameter to xylem width.

6. Comparison of leaf structures between two plant species and their xerophytic adaptations; water potential variation explained by transpiration rates.