Biology 9700/23 Oct Nov 2011 | Cambridge AS Level Past Papers With Mark Scheme

1. Bacterial cell structure analysis using electron micrographs; comparison to animal cells lacking organelles like nucleus, Golgi apparatus, and mitochondria.

2. Functionality of heart structures: sinoatrial and atrioventricular nodes, bicuspid valve, and graphical interpretation of cardiac cycle blood pressure data.

3. Transpiration pathway from leaf to atmosphere; adaptations in Camellia sinensis leaves grown under high sunlight, including thicker cuticle and more palisade cells.

4. Global HIV infection trends; factors contributing to reduction in new cases, impact of preventative measures, and relation between new infections and HIV-related deaths.

5. DNA structure and replication mechanism; roles of transfer RNA in polypeptide synthesis and its interaction with ribosomes and messenger RNA.

6. Ecological interactions in mangrove food chains; energy transfer inefficiency, nitrogen recycling via decomposers, and conversion of nitrates for plant uptake.