Biology 9700/04 May June 2004 | Cambridge AS Level Past Papers With Mark Scheme

1. Factor VIII glycoprotein: structural stability through hydrogen bonds, disulfide bridges, and hydrophobic interactions; recombinant Factor VIII advantages over blood-derived alternatives.

2. Mitochondrial adaptations for oxidative phosphorylation: extensive inner membrane folds (cristae) and compartmentalization for enzyme and substrate concentration.

3. Proximal convoluted tubule adaptations for selective reabsorption: brush border microvilli for surface area, mitochondria for ATP production, and tight junctions to prevent leakage.

4. Sickle cell allele high prevalence linked to malaria resistance in heterozygotes; mutation impacts hemoglobin's structure and oxygen-carrying efficiency.

5. X-linked inheritance of coat color in cats; tortoiseshell patterns from random X-chromosome inactivation.

6. Synapse function: neurotransmitter release, receptor binding, and signal transmission across synaptic cleft; glucagon's role in increasing blood glucose via glycogenolysis and gluconeogenesis.

7. Calvin Cycle: RuBP carboxylation, G3P production, and RuBP regeneration; NADP's role as a hydrogen and electron carrier in photosynthesis.