Biology 9700/13 Oct Nov 2010 | Cambridge AS Level Past Papers With Mark Scheme

1. Xerophytic adaptations in leaves, including sunken stomata, thick cuticles, and small surface area-to-volume ratios.
2. Water transport in plants, driven by evaporation, diffusion, and water potential gradients between roots and leaves.
3. Structural features of xylem and phloem, including mature vessel elements, sieve tube elements, and absence of cytoplasm or nucleus in xylem.
4. Properties of water as a solvent, roles in condensation reactions, and its thermal properties critical for biological functions.
5. Enzyme activity in hydrolysis and condensation reactions, with specificity for substrates and active site dynamics.
6. Amylopectin and glycogen structural differences, including glycosidic bond patterns and branching frequency.
7. DNA replication roles of helicase, DNA polymerase, and single-strand binding proteins, emphasizing the semi-conservative mechanism.
8. Human circulatory and respiratory system adaptations, with cardiac valves, lung structure, and impacts of smoking on cardiovascular health.
9. Energy flow in ecosystems, pyramid structures for energy transfer, and roles of decomposers, consumers, and nitrogen cycle microorganisms.