Biology 9700/33 Oct Nov 2011 | Cambridge AS Level Past Papers With Mark Scheme

1. Estimation of protein concentration in milk using biuret reaction; serial dilution of milk samples to create a gradient for comparison.

2. Recording color intensity changes in milk samples after reaction with potassium hydroxide and copper sulfate; categorization using a numerical scale.

3. Investigation of protein digestion rates by protease, effect of flow rates on enzymatic activity, and graphical representation of results.

4. Microscopic analysis of mammalian organ sections; plan diagrams of stained layers and calculation of tissue dimensions using photomicrograph magnifications.

5. Comparison of organ structures across mammalian species; observable differences in layer organization and adaptation for molecule absorption.

6. Experimental accuracy improvements via finer dilution gradients and increased replicates for enhanced protein concentration estimation.