Biology 9700/43 May June 2023 | Cambridge AS Level Past Papers With Mark Scheme

1. Krebs cycle intermediates and ATP production via substrate-level phosphorylation, emphasizing universal energy roles of ATP.

2. Antibiotic resistance development in bacteria through mutations and natural selection, highlighting selective pressures in microbial populations.

3. Regulation of gene expression in prokaryotes, focusing on the lac operon mechanism, the role of repressor proteins, and advantages of repressible operons.

4. Treatment approaches for SCID, comparing enzyme replacement therapy, bone marrow transplants, and gene therapy, including ethical implications.

5. Dihybrid inheritance in fish, utilizing Punnett squares and chi-squared analysis to examine phenotypic ratios and gene linkage on sex chromosomes.

6. Kidney ultrafiltration process, involving the role of the glomerulus, Bowman’s capsule, and ADH in regulating water reabsorption.