Diffusion

• Diffusion is the net movement of particles from an area of high concentration to an area of low concentration. 
• True or false? If molecules are left alone they'll move around randomly.

  true
• In which of the following states can molecules diffuse?

  gas

  liquid
• Cell membranes are said to be 'partially permeable'. What does this mean?

  Only some molecules can pass through the membrane
• Which molecules are able to diffuse into and out of cells?

  Amino acids

  Glucose

  Water
• List three factors that affect the rate of diffusion?

  Concentration gradient 

  Temperature 

  Surface area

  Distance to diffuse across (if diffusing across a membrane)
• Will a larger surface area increase or decrease the rate of diffusion?

  Increase 

  A larger surface area means a larger area over which molecules can diffuse.
• Why does a higher temperature increase the rate of diffusion?

  Higher temperature means particles have more (kinetic) energy

  So they move around faster 

  And can diffuse more quickly