Biology 9700/51 May June 2011 | Cambridge AS Level Past Papers With Mark Scheme

1. Investigation of water potential in potato tubers of varying ages using sucrose solutions to assess mass changes in tissues near buds and central regions.

2. Statistical significance of water potential differences tested with a t-test; analysis supports starch-to-sugar conversion in tuber regions near growth areas.

3. Validation of conclusions regarding sugar and starch distributions using further investigations like biochemical tests (iodine for starch, Benedict's for reducing sugars).

4. Organo-mercury compound effects on mitosis in white blood cells observed via abnormalities in spindle formation and chromosome clumping.

5. Data reliability enhanced through observing large cell samples (n=100) and controlled conditions, correlating organo-mercury concentrations with mitotic disruption.

6. Line graph plotting normal mitosis frequency against compound concentration highlights dose-dependent cytotoxic effects inhibiting cell division.