Diffusion

• Diffusion is the net movement of particles from an area of ______  concentration to an area of _____ concentration. 

  higher

  lower
• True or false? If molecules are left alone they'll move around randomly.

  True - molecules have kinetic energy which means that they'll constantly be moving. 
• In which states can molecules diffuse?

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

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

  Amino acids, water and glucose

  Only small molecules such as water, glucose, and amino acids, can diffuse into/out of cells. Large molecules like proteins and starch are too big. 
• List three factors that affect the rate of diffusion.

  
  

  Concentration gradient 

  Temperature 

  Surface area
• 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