Biology 9700/43 May June 2019 | Cambridge AS Level Past Papers With Mark Scheme

1. Functional roles of synapses in the nervous system, including voltage-gated channels, acetylcholine interactions, and synaptic enzyme functions.

2. Genetic and molecular mechanisms underlying albinism and ocular albinism, including mutation effects, genetic inheritance patterns, and the impact of gene deletions on protein functionality.

3. Environmental and genetic influences on cilia length in epithelial cells, gene regulation via regulatory proteins, and the role of microarray analysis in identifying gene expression patterns.

4. Genetic engineering techniques for insect-resistant GM rice, T2A-1, including integration of insecticidal genes and environmental implications of GM crop cultivation compared to traditional methods.

5. Mechanisms of water potential regulation in the kidney, involving ADH action on aquaporins, homeostatic responses to environmental stimuli, and feedback mechanisms maintaining blood water potential.

6. Evolutionary theories explaining regressive traits like eye loss in cavefish, genetic drift versus natural selection, and mitochondrial DNA comparisons to determine species relationships.

7. Processes in anaerobic respiration in yeast, including glycolytic stages, reduced ATP yield under anaerobic conditions, and stepwise biochemical reactions producing ethanol and CO₂.