Active transport

• Active Transport

  Substances need to be absorbed against a concentration gradient, i.e. from a lower to a higher concentration
• Root Hairs

  • Stick out into the soil
  • Give the plant a large surface area for absorbing water and mineral ions from the soil
  • Plants need these mineral ions for healthy growth
  • Concentration of minerals is usually higher in the root hair cells than in the soil around them
• Root Hairs Take in Minerals Using Active Transport

  1. Minerals should move out of the root hairs if they followed the rules of diffusion

  2. Root hair cells use active transport to absorb minerals from a very dilute solution, against a concentration gradient

  3. Active transport needs energy from respiration to make it work
• Active Transport in the Gut

  • Used when there is a lower concentration of nutrients in the gut but a higher concentration of nutrients in the blood
  • Allows nutrients to be taken into the blood, despite the fact that the concentration gradient is the wrong way
• Diffusion vs Active Transport

  Diffusion does not require energy, active transport does require energy