3. Movement in and out of cells

• Diffusion: the net movement of particles from an area of high concentration to an area of low concentration
• Osmosis: the movement of fluid from a high concentration to a low concentration through a semi-permeable membrane
• Active transport: movement of particles through a cell membrane from a region of low concentration to a region of high concentration using energy from respiration
• Factors influencing faster diffusion:

  • larger concentration gradient
  • higher temperature
  • larger surface area
• Osmosis rules:

  • conc. of soluble outside = inside -> no change in size
  • conc. of solute outside > inside ->shrinks (plasmolysis)
  • conc. of solute outside < inside -> swells (turgid)