Biology GCSE AQA Higher Paper 1 Revision Part 2

4. Surface Area to Volume Ratio (SA:V) Small organisms: Have a large SA:V,

allowing efficient diffusion across their surface.Large organisms: Have a small SA:V and

require specialized exchange surfaces.Adaptations for Exchange: Thin membranes (short diffusion path),

large surface area (villi in small intestine, alveoli in lungs), and efficient blood

supply to maintain steep concentration gradients. 5. Required Practicals

For the 2026 exam, focus on: RP 1 (Microscopy): Use a light microscope to observe and draw plant/animal cells.RP

2 (Microbiology - Triple Only): Investigate the effect of antibiotics or antiseptics on

bacterial growth using agar plates and measuring zones of inhibition.RP 3 (Osmosis): Investigate