1.9

• Active transport

  Process that allows cells to move substances from an area of low concentration to an area of high concentration, against the concentration gradient
• People with cystic fibrosis have thick, sticky mucus in their lungs, gut and reproductive systems because an active transport system in their mucus-producing cells does not work properly
• Diffusion and osmosis

  • Not enough for all cell needs
• How substances move in and out of cells

  1. Diffusion down a concentration gradient

  2. Active transport against a concentration gradient
• Rate of active transport

  Depends on rate of respiration
• Energy needed for active transport

  Produced during cell respiration
• Cells involved in a lot of active transport usually have many mitochondria
• Examples of active transport

  • Root hair cells in plants
  • Cells lining gut
• Active transport is widely used in cells