Biology 9700/04 Oct Nov 2007 | Cambridge AS Level Past Papers With Mark Scheme

1. Measurement of unicellular organism sizes using scale calibration and kingdom classification; structural comparisons, including cell wall presence.

2. Biodiversity in tropical rainforests: high species richness driven by structural complexity and resource variety; conservation importance linked to ecological stability and genetic reservoirs.

3. Cystic fibrosis (CF): genetic inheritance via autosomal recessive mutations, symptoms analysis, and gene-sequence mutations impacting amino acid changes in polypeptides.

4. Glucose biosensors: glucose oxidase reaction monitoring for hypoglycemia detection through gluconic acid production.

5. C4 photosynthesis: maize adaptations to high temperatures, structural differences enabling efficiency, and comparison to wheat under thermal stress.

6. IVF challenges: declining success rates with age, public funding debates linked to cost-benefit considerations, and ethical implications.

7. Krebs cycle enzymes: succinate dehydrogenase activity influenced by aluminum ions, role in fumarate production, and ATP generation mechanisms.

8. Action potentials: stages of depolarization and repolarization in neurons, threshold stimulus requirements, and membrane potential dynamics.

9. Sickle cell anemia-malaria relationship: genetic advantages in malaria-endemic regions, distribution patterns, and heterozygote resistance benefits.

10. Meiosis and fertilization contributions to genetic variation; environmental effects on phenotype variability exemplified by temperature or nutrient availability.