Diffusion

• Diffusion


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


  • The simplest type is when different gases diffuse through each other
  • The faster the concentration gradient, the faster the diffusion rate
  • Larger particles move around faster and give a faster diffusion rate
• Cell membranes


  They hold the cell together but they let stuff in and out as well
• Cell membranes


  • Dissolved substances can move in and out of cells by diffusion
  • Only very small molecules can diffuse through cell membranes - things like oxygen, carbon dioxide, glucose, amino acids and water
  • Larger molecules like ash and proteins can't pass through the membrane
  • Substances diffuse through the cell membrane from where there's a higher concentration to where there's a lower concentration
• The larger the surface area of the membrane, the faster the diffusion rate because more particles can pass through at once
• Diffusion


  Particles spreading out