Biology 9700/31 Oct Nov 2012 | Cambridge AS Level Past Papers With Mark Scheme

1. Investigation of glucose diffusion from plant extract through Visking tubing; serial dilution preparation of glucose solutions and Benedict's test for endpoint detection.

2. Recording diffusion rates based on color change timing, sample placement in glucose concentration series, and confidence improvements through additional modifications.

3. Absorbance of light by colored solutions measured using a colorimeter, with absorbance data plotted to analyze glucose diffusion trends.

4. Differences in glucose concentration gradients impacting diffusion rates, with systematic error identified in measuring cylinder readings for solution volumes.

5. Large plan diagram of plant root transverse section, detailed xylem vessel drawing with annotations, and calibration of eyepiece graticule for precise measurements.

6. Comparison of root and plant organ specimens, focusing on vascular tissue and other observable structural differences between samples.