Biology 9700/21 Oct Nov 2010 | Cambridge AS Level Past Papers With Mark Scheme

1. Trophic levels in ecosystems: role of producers and consumers, energy transfer inefficiency due to metabolic heat and indigestible material.

2. Gas exchange system anatomy: presence of cartilage, ciliated epithelium, and goblet cells across trachea, bronchi, and alveoli.

3. Vital capacity measurement in athletes, tidal volume calculation, and cardiovascular limitations due to atherosclerosis affecting blood flow.

4. Effects of nicotine and carbon monoxide on cardiovascular health: vasoconstriction, increased heart rate, reduced oxygen transport, and plaque development.

5. Osmosis impact on red blood cells in varying sodium chloride concentrations: water potential gradients causing cell swelling or crenation.

6. Hemoglobin function: oxygen transport via oxyhemoglobin and carbon dioxide transport as bicarbonate ions or bound to proteins.

7. High-altitude adaptation: increased haematocrit and red blood cell count enhancing oxygen-carrying capacity under reduced oxygen pressure.

8. Cholera transmission via contaminated water, epithelial chloride ion loss mechanisms, immune response analysis post-vaccination, and challenges in disease control.

9. Cellulose structure: β-glucose subunits linked by glycosidic bonds, high mechanical strength due to hydrogen bonding, and cell wall synthesis pathways.

10. Protein synthesis and transport: roles of organelles like ribosomes, Golgi apparatus, and vesicles in delivering enzymes for cell wall expansion.