2.4

• diffusion - particles spread out from an area of high concentration to an area of low concentration
• diffusion 


  “Balancing out” or “evening out” process that continues until the concentration of particles is the same everywhere
• cell membrane

  • These openings only allow SOME particles to pass through
  • This is called semi-permeable or selectively permeable
  • Ex. Oxygen and Water are both small enough to pass through most membranes
  • The amount of each of these needs to remain constant
• permeable - all things can pass through the membrane
• semi - permeable - some things can go through, others cannot
• impermeable - nothing can go through the membrane
• • Selectively permeable only some things can go through, but the membrane can pick what will go through 
• osmosis - the movement of water particles through a membrane

  • Moves from an area of higher to lower concentration until the concentration of water is the same on both sides
• hypertonic solutions - when there is a high amount of solute outside the cell, so water from inside moves out
• hypotonic solutions - when there is a high concentration of solute particles inside the cell, so water moves into the cell
• isotonic solution - there is an equal amount of solute inside and outside of the cell