Biology 9700/31 May June 2012 | Cambridge AS Level Past Papers With Mark Scheme

1. Plasmolysis in onion cells exposed to sodium chloride solutions; comparison of cell morphology under 1.00 mol dm\\(^{-3}\\) NaCl vs. water.

2. Quantitative analysis of plasmolysis levels to determine unknown sodium chloride concentrations; use of large adjacent cell drawings for structural comparison.

3. Explanation of osmotic changes in cells post-water exposure, emphasizing vacuole expansion and reduced plasmolysis.

4. Modified experimental setup for determining onion cell water potential, involving varied NaCl solutions and observation of incipient plasmolysis.

5. Iodine staining effects on sweet banana tissues; pattern analysis and annotated diagrams highlighting starch distribution.

6. Ratio of transverse section width to outer skin width in bananas; chart plotting of nutrient composition comparing plantain and sweet banana.

7. Calculation of water content differences between plantain and sweet banana using percentage mass data.