Biology 9700/52 May June 2012 | Cambridge AS Level Past Papers With Mark Scheme

1. Investigation of hybridization in grass species, analysis of chromosome counts in embryo plants, and controlled use of plastic bags to prevent cross-contamination.

2. Experimental procedure for pollen transfer between species, safety precautions, and chromosome visibility methods using staining techniques.

3. Chromosome counts in hybrids, explanation of results showing genetic contributions from parent species, and successful breeding potential analysis.

4. Statistical analysis of fruit germination rates in hybrids, calculation of mean, mode, and median, and null hypothesis formulation for t-test.

5. Temperature effects on cell membrane permeability, standardized variable control, and analysis of chloride ion release rates across temperature gradients.

6. Prediction of ethanol's impact on ion release rates, emphasizing increased membrane disruption and chloride ion leakage under ethanol exposure.