Biology 9700/04 Oct Nov 2004 | Cambridge AS Level Past Papers With Mark Scheme

1. Photosynthesis processes: chlorophyll photoactivation, ATP formation via chemiosmosis, and advantages of thylakoid membrane arrangement for light-dependent reactions.

2. Membrane potential changes in neurons: resting potential maintenance, depolarization via sodium influx, repolarization through potassium efflux, and differences in hormonal vs. nervous communication.

3. Blood lactate accumulation: formation via anaerobic respiration, correlation with oxygen debt, and improved lactate threshold in trained athletes due to enhanced oxygen delivery.

4. Sickle cell genetics: inheritance patterns using allele symbols, genotype probability in offspring, and implications of heterozygous advantage in malaria-endemic regions.

5. Speciation in pupfish: evolution due to geographic isolation, environmental stabilizing forces, and potential genetic mixing if habitats reconnect.

6. Krebs cycle features: enzyme-mediated steps, role of NAD in electron transport and ATP production, and its significance in aerobic respiration.

7. Recombinant DNA technology: insulin synthesis in bacteria via plasmid vectors, advantages of human insulin for diabetic treatment, and reduced allergic reactions compared to animal-derived insulin.