Biology 9700/11 May June 2010 | Cambridge AS Level Past Papers With Mark Scheme

1. Biological structures measured in micrometers and nanometers: chloroplasts, ribosomes, and xylem vessels compared.

2. Features of eukaryotic cells: presence of endoplasmic reticulum, nucleoli, and protein-DNA association as distinguishing characteristics.

3. Experimental measurements prone to parallax errors: length via ruler, volume via measuring cylinder, and eyepiece graticule usage.

4. Food sample analysis: identification of lipid, protein, starch, and reducing sugar using biochemical tests like Biuret, Benedict's, and iodine solution.

5. Starch molecular structure and function: amylopectin branching for energy storage, compactness for transport, and insolubility minimizing osmotic effects.

6. Hemoglobin as a globular protein: quaternary structure with hydrophilic outer regions enhancing solubility and oxygen transport efficiency.

7. Enzyme activity affected by temperature: denaturation point visualized through reaction completion time, emphasizing optimal temperature ranges.

8. Photosynthesizing leaf's sieve tube elements: sugar export and water potential gradients, contrasted with sugar import in root tissues.

9. Nitrogen cycle microbial roles: decomposers, nitrifying, and denitrifying bacteria converting ammonium ions and nitrates in soil ecosystems.

10. Primary and secondary immune responses: memory B-lymphocyte activation enhancing antigen-specific antibody production upon re-exposure.