Active transport

• Active transport


  The movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration, requiring energy from cellular respiration
• Diffusion


  The process by which substances move down their concentration gradient from a region of higher concentration to a region of lower concentration, a passive process that does not require energy
• Active transport


  • Occurs across a membrane
  • Requires special proteins in the membrane to transfer molecules
• Cellular respiration


  The process that happens mainly in the mitochondria when they break down glucose to release energy, providing the energy for active transport
• ATP


  Molecules that act like little batteries, taking the energy from the mitochondria to the different parts of the cell that need it
• Active transport


  1. Movement of molecules against their concentration gradient

  2. Requires energy from cellular respiration
• Root hair cells


  • Adapted to absorb water and mineral ions by having a large surface area and many mitochondria
• Mineral ions needed by plants

  At a higher concentration inside the root hair cells than in the soil, so they cannot be absorbed by diffusion and must use active transport