Biology 9700/02 Oct Nov 2007 | Cambridge AS Level Past Papers With Mark Scheme

1. Binary fission in bacteria: structural features of prokaryotes absent in eukaryotes, including cell wall composition and plasmids.

2. Haemoglobin structure: tertiary and quaternary folding, role of heme groups in oxygen binding, and dissociation curve adaptations for oxygen delivery to tissues.

3. Xylem vessel adaptations: lignified walls for water transport, mechanisms of cohesion and adhesion, and effects of hazardous tobacco substances on health.

4. Cardiac cycle dynamics: electrical activity source in the SAN, coordination of atrial and ventricular contractions, and pressure differences between ventricles due to pulmonary vs. systemic circulation.

5. Tuberculosis (TB): transmission via airborne droplets, regional variations in case impact, and challenges in eradication despite vaccine availability.

6. Ecosystem dynamics: energy inefficiency limiting large carnivores, nitrogen fixation by leguminous plants supporting growth in nutrient-poor soils, and examples of ecosystem size and scale.