Biology 9700/22 May June 2017 | Cambridge AS Level Past Papers With Mark Scheme

1. Cell structure and organelle functions: Completion of Table 1.1 focusing on cell types like palisade mesophyll and Leydig cells, detailing their functions and associated organelles such as chloroplasts and Golgi bodies.
2. Tissue and organ differentiation: Explanation of the aorta’s classification as an organ based on its structural complexity and diverse tissue types, highlighting its role in systemic circulation.
3. Enzyme activity and pH effects: Analysis of the bacterial lipase activity across different pH levels, describing trends in enzyme efficiency and the implications for industrial applications.
4. Malaria transmission cycle: Identification of Plasmodium species infecting humans, the role of Anopheles mosquitoes in the disease cycle, and the advantages of electron microscopy for observing Plasmodium cells.
5. Meristematic cells and cell cycle: Explanation of the cell cycle stages in meristematic cells, the role of cytokinesis, and the significance of semi-conservative DNA replication during the S phase.
6. Defence mechanisms in the respiratory system: Role of ciliated epithelium and alveolar macrophages in protecting against pathogens like Streptococcus pneumoniae, and structural changes in alveoli associated with emphysema.
7. Sucrose transport in plants: Description of the process of sucrose loading into phloem sieve tubes, and the concept of a strong sink in plant physiology.
8. Protein structure and gene expression: Comparison of the quaternary structures of antibody and haemoglobin molecules, and transcription and translation processes leading to specific amino acid sequences.