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


  • Takes place across a membrane
  • Requires special proteins in the membrane to transfer molecules from one side to the other
• 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
• Root hair cells


  • Have a large surface area for absorption
  • Have lots of mitochondria to provide energy for active transport
• Active transport in root hair cells

  1. Absorb water and mineral ions from the soil

  2. Minerals are at a higher concentration inside the cell than outside, so they cannot be absorbed by diffusion

  3. Use active transport to move the minerals against their concentration gradient

  4. Require energy from cellular respiration in the mitochondria to power the active transport
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