Biology 9700/23 May June 2015 | Cambridge AS Level Past Papers With Mark Scheme

1. Fluid mosaic model: structural properties, comparison with Davson-Danielli model, and mechanisms of active transport and protein denaturation at high temperatures.

2. DNA replication timing in the cell cycle, hydrogen bonding between bases, and mutagenic effects of benzopyrene.

3. Plasma cell structure and function, magnification calculation, smallpox vaccination efficacy, and mechanisms of long-term immunity.

4. Blood pressure variations in systemic circulation, vein structural adaptations, angiotensin regulation, and competitive inhibition of ACE.

5. Role of magnesium in photosynthesis, water properties supporting aquatic life, transport system necessity in multicellular organisms, and phloem sugar transport.

6. Nitrogen cycle: nitrification and denitrification processes, oceanic ecosystem dynamics, and definitions of ecosystem, producer, and habitat.