AHL Topic Revision — High-Yield Additional HL Content
AHL questions appear primarily in Section B of Paper 2 and in roughly 25% of Paper 1A. We hit the highest-return AHL themes first.
- Theme A1.2 — nucleic acids: directionality of DNA, semiconservative replication, RNA processing depth
- Theme B2.3 — transport: water and mineral uptake, transpiration, mass flow hypothesis, blood flow regulation
- Theme C1.2 — enzymes & metabolism: induced-fit model, cofactors, metabolic pathway control, inhibition kinetics
- Theme C4.2 — ecosystem stability: tipping points, ecological succession depth, carbon cycle feedback loops
- Theme D3.3 — homeostasis: thermoregulation extensions, osmoregulation in the nephron, hormonal feedback loops
- Daily 20-question AHL recall quiz to consolidate before moving on