Diffusion

• Diffusion


  Particles move about randomly, and after a bit they end up evenly spaced
• Diffusion is not rocket science
• Diffusion


  The gradual movement of particles from places where there are lots of them to places where there are fewer of them-it's just the natural tendency for stuff to spread out
• Diffusion


  The spreading out of particles from an area of higher concentration to an area of lower concentration
• Diffusion happens in both solutions and gases because the particles in these substances are free to move about randomly
• Types of diffusion


  • Different gases diffusing through each other
• The bigger the concentration gradient (the difference in concentration)


  The faster the diffusion rate
• A higher temperature


  Gives a faster diffusion rate because the particles have more energy and move around faster
• Cell membranes


  • Hold the cell together
  • Let stuff in and out
• Diffusion through cell membranes

  Dissolved substances can move in and out of cells by diffusion
• Molecules that can diffuse through cell membranes

  • Oxygen (needed for respiration)
  • Glucose
  • Amino acids
  • Water
• Molecules that cannot diffuse through cell membranes

  • Starch
  • Proteins
• Particles flow through the cell membrane

  From where there's a higher concentration to where there's a lower concentration
• Larger surface area of the membrane

  Faster the diffusion rate, because more particles can pass through at once