Biology 9700/31 May June 2023 | Cambridge AS Level Past Papers With Mark Scheme

1. Investigation of catalase activity in yeast, assessing the effect of pH on the rate of oxygen release using immobilized yeast beads in hydrogen peroxide.

2. Use of buffer solutions to maintain specific pH levels and timing of bead rise to quantify enzymatic activity under varying conditions.

3. Modification of procedures to explore substrate concentration effects, emphasizing experimental control and reliable data collection.

4. Analysis of enzyme kinetics, including interpretation of Michaelis-Menten constant (Km) for lactase activity at different lactose concentrations.

5. Comparison of lactose concentration in milk across mammalian species, with results visualized in bar chart format.

6. Examination of plant leaf sections for anatomical differences, identifying xerophytic adaptations like sunken stomata and thick cuticles for water conservation.