Biology 9700/33 Oct Nov 2010 | Cambridge AS Level Past Papers With Mark Scheme

1. Effect of copper sulfate on methylene blue-stained plant tissue: concentrations prepared using dilution, observations after soaking, and permeability effects on cell membranes.

2. Errors in copper sulfate experiments include inconsistent plant tissue preparation, residual methylene blue, and timing inaccuracies; proposed improvements focus on standardization and precise timing.

3. Plan diagram of a quarter-section of a plant organ showing cortex and endodermis; high-power drawing of xylem vessel and adjacent cells.

4. Comparative analysis of transverse sections of different plant organs, recording structural differences between specimens.

5. Phloem sieve tube element contents charted: sucrose, ammonium, calcium, magnesium, and sodium ions; calculation of calcium ion percentage difference between phloem and xylem.

6. Absence of sucrose in xylem explained by transport limitations to sieve elements, indicating active loading of sucrose into phloem tissues for translocation.