Biology 9700/42 Oct Nov 2023 | Cambridge AS Level Past Papers With Mark Scheme

1. Comparison of ethanol and lactate fermentation pathways, identifying key intermediates like pyruvate and NADH, ensuring ATP production in anaerobic conditions.

2. Adaptations of rice plants for submerged growth, such as aerenchyma formation and anaerobic respiration tolerance in roots.

3. Yeast reproductive cycles, distinguishing between mitosis for asexual reproduction and meiosis during spore formation, contributing to genetic variation.

4. Principles of selective breeding in crops, emphasizing disease resistance and associated risks like reduced genetic diversity.

5. Genetic engineering in plants, using fluorescent marker genes to confirm successful expression of desired traits, with applications like herbicide resistance.

6. Analysis of dihybrid inheritance in fruit flies, employing chi-squared tests to assess gene linkage and deviations from expected Mendelian ratios.