Biology 9700/03 Oct Nov 2004 | Cambridge AS Level Past Papers With Mark Scheme

1. Preparing a 1 mol dm⁻³ carbohydrate solution: weighing and dissolving steps; potato strip osmosis experiments to measure percentage length changes.

2. Improving reliability in osmosis experiments through increased replication and precise cutting techniques.

3. Graphing percentage length change of potato strips against sucrose solution concentrations; determining isotonic concentration from the graph.

4. Water potential gradient explanation for length changes in potato strips placed in pure water.

5. High-power drawings of frog and human blood cells; structural differences noted: frog cells are nucleated, human cells are anucleate.

6. Calculations comparing human white blood cell diameter with red blood cells using eyepiece graticule; ratio analysis for cell size comparisons.

7. Frog and human red blood cell distinctions: nucleation presence in frog cells, lack in human cells; structural adaptations to oxygen transport.