Biology 9700/42 May June 2024 | Cambridge AS Level Past Papers With Mark Scheme

1. Osmoregulation mechanisms involving osmoreceptors, antidiuretic hormone (ADH), and their effects on urine production analyzed through graphical data.

2. Causes of phenotypic variation, including genetic and environmental factors, linked to evolutionary theory supported by DNA sequence comparisons.

3. Inheritance patterns in tortoise beetles analyzed using genetic crosses, codominance, and dominance hierarchy within alleles.

4. Gene-protein-phenotype relationships explained through examples like haemophilia, alongside mechanisms regulating plant growth and dwarfism.

5. Genetic testing of BRCA1 mutations linked to increased cancer risk; PCR and DNA sequencing applications in detecting mutations, with population-level cancer risk calculations.

6. Cellular processes such as oxidative phosphorylation, mitochondrial DNA functions, and photosynthetic oxygen production under varying conditions discussed.

7. Synaptic transmission influenced by opioids like morphine, detailed through mechanisms involving ion channels and synaptic function.

8. Ecological impact of invasive species like the Asian common toad assessed, alongside conservation methods like IVF for endangered species.

9. Homeostasis in blood glucose regulation explained with reference to diabetes, test strip reactions, and biosensor advantages.