Biology 9700/52 May June 2013 | Cambridge AS Level Past Papers With Mark Scheme

1. Investigation of gibberellin (GA) effects on barley seed germination and early growth, including the concentration and optimum conditions for growth enhancement.

2. Serial dilution of GA solutions for experimental setup, observation of germination rates, and measurement of early plant growth.

3. Calculation and interpretation of percentage growth differences between treated and untreated barley seeds to assess GA effectiveness.

4. Application of t-tests to analyze statistical significance between control and experimental groups, formulation of null hypothesis for germination rate differences.

5. Growth of Aerobacter aerogenes under anaerobic and aerobic conditions, including bacterial population estimation using a counting grid.

6. Reliability concerns in bacterial growth data, explanation of population trends under changing oxygen levels, and precautionary measures in microbial culture maintenance.