Biology 9700/42 March 2020 | Cambridge AS Level Past Papers With Mark Scheme

1. Structural features and functions of the proximal convoluted tubule in the nephron, including co-transport and active transport mechanisms.

2. Diagnosis and genetic basis of severe combined immunodeficiency (SCID) using PCR and gene therapy approaches for enzyme deficiencies.

3. Genetic inheritance patterns in flower color of Ipomoea purpurea based on dihybrid crosses and pigment production.

4. Application of the Hardy-Weinberg principle in commercial fish populations, selective breeding techniques, and genetic modification in aquaculture.

5. Role of plasmids and fluorescent markers in recombinant DNA technology, restriction enzyme applications, and gene insertion techniques.

6. Classification, genetic bottlenecks, and ecological roles of sea otters as keystone species in kelp forests, alongside the effects of their absence on food web dynamics.