AQA GCSE BIOLOGY B3.1

AQA GCSE BIOLOGY B3.1

1. DIFFUSION

   • Diffusion is the movement of particles from an area of high concentration to an area of low concentration
     • The greater the difference in concentration the faster the rate of diffusion

2. OSMOSIS

   • Osmosis is the diffusion of water from a dilute to a more concentrated solution, through partially permeable membrane

3. ACTIVE TRANSPORT

   • Active transport is the movement of particles against a concentration gradient
     • This requires energy from respiration
     • This enables cells to absorb ions from more dilute solutions
       • E.g. Plant roots can absorb ions from the soil solution, even if the concentration of the ions is lower than the cytoplasm.