Biology 9700/42 Oct Nov 2013 | Cambridge AS Level Past Papers With Mark Scheme

1. Huntington’s disease caused by dominant huntingtin gene allele; relationship between CAG repeat number and symptom onset age.

2. Evolution of woolly mammoth through variation and natural selection; amino acid differences in haemoglobin affecting cold adaptation.

3. ATP components and role in cellular energy transactions; variation in ATP yield from different respiratory substrates like glycogen and palmitic acid.

4. Hormonal regulation in the menstrual cycle; roles of oestrogen, progesterone, and luteinizing hormone (LH).

5. Maize yield improvement through hybridization techniques; genetic uniformity in single-cross hybrids compared to double-cross hybrids.

6. Myelination and axon diameter effects on nerve impulse conduction speed; impacts of multiple sclerosis on sensory transmission.

7. Light color effects on photosynthesis rates using hydrogencarbonate indicator; roles of accessory pigments in photophosphorylation.

8. Decline in tiger populations and factors leading to species endangerment; reasons behind conservation challenges for specific species.

9. Gibberellin roles in seed germination; stimulation of amylase production and starch hydrolysis supporting embryonic growth.

10. Gene mutation definitions and consequences; faulty CFTR proteins causing cystic fibrosis symptoms.

11. Features of plant kingdom organisms; mitochondrial structure and function in plant cells.