Biology 9700/52 May June 2011 | Cambridge AS Level Past Papers With Mark Scheme

1. Osmosis investigation in plant storage tissue using sucrose solutions and colored cell sap; rate of droplet movement as a density indicator for water potential determination.

2. Control of independent (sucrose concentration) and dependent (rate of droplet movement) variables, with potential uncontrolled variables like temperature and solution mixing.

3. Microscopic observations of plant cells in hypotonic (0.2 M sucrose) and hypertonic (0.8 M sucrose) environments; prediction of turgid or plasmolyzed states based on water movement.

4. Female infertility research on FF-MAS stimulating meiosis; experimental procedures including oocyte culture, compound concentration tests, and statistical analysis of meiosis stimulation rates.

5. Statistical test application (e.g., t-test) to compare FF-MAS effects with other activators; conclusions drawn about receptor activation and standard error implications for mean data reliability.

6. Evidence for FF-MAS as a specific activator of LXR alpha based on concentration-dependent stimulation and comparison with other compounds like cholesterol.