Biology 9700/33 May June 2015 | Cambridge AS Level Past Papers With Mark Scheme

1. Identification of solutions (S1, S2, S3) based on carbohydrate tests using Benedict’s and iodine reagents for glucose and starch detection.

2. Effects of water potential differences on onion epidermal cells, leading to plasmolysis in hypertonic solutions and turgidity in hypotonic solutions.

3. Use of onion tissue to observe cellular changes under varying solute concentrations; drawing and labeling cytoplasmic effects in different solutions.

4. Investigation of water evaporation rates using model setups with different lid hole numbers; measurement of water loss and graph plotting.

5. Control setup in evaporation experiments to ensure validity, with modifications like increased airflow to enhance evaporation rates.

6. Calibration of eyepiece graticule for accurate tissue measurement; conversion of units from mm to μm for precise microscopic analysis.

7. Plan diagram of plant stem transverse section, emphasizing clear tissue boundaries and proportional representation.