Biology 9700/04 Oct Nov 2002 | Cambridge AS Level Past Papers With Mark Scheme

1. Calvin cycle analysis: glycerate phosphate (GP) concentration increases after light removal due to reduced RuBP regeneration; RuBP decreases as it cannot be replenished without ATP and NADPH from photophosphorylation.

2. Mitochondria structure: cristae for oxidative phosphorylation and matrix for Krebs cycle; adaptations include large surface area for electron transport and localized enzymes.

3. Liver functions: Kupffer cells detoxify blood, remove pathogens, and recycle red blood cells; hepatocytes synthesize bile, metabolize fats, and convert ammonia to urea for kidney excretion.

4. Meiosis II stages: identification of anaphase II; subsequent events include chromatid separation and cell division, with genetic variation introduced via crossing over and independent assortment.

5. Scallop genetics: analysis of offspring shell color ratios explained by allele dominance; methodology for pure-breeding orange scallops involves selective breeding of offspring exhibiting homozygosity for the orange allele.