Transport

• Diffusion


  1. The random movement of particles from an area of high concentration to an area of low concentration

  2. It requires no extra energy

  3. Only works in gases and liquids (not solids)
• Diffusion


  • How oxygen moves from the lungs to the blood
• Active transport


  1. The movement of particles from an area of low concentration to an area of high concentration across the cell membrane

  2. Requires energy

  3. and a carrier protein
• Active transport


  • How glucose gets into cells / mineral ions get into roots (normally)
• Osmosis


  1. The motion of water molecules from an area of high water concentration to an area of low water concentration

  2. across a semi-permeable membrane
• Plant or animal tissues placed in a concentrated salt/sugar solution


  Water moves out of the tissue by osmosis from a high water concentration (inside the tissue) to a low water concentration (outside)
• Plant or animal tissues placed in pure water

  Water moves into the tissue by osmosis from a high water concentration (outside) to a low water concentration (inside the tissue)
• Calculating percentage change by mass of plant or animal tissue in water or solution

  (Final mass/starting mass ) x100
• The figure can be negative if mass decreases