Factors affecting the rate of facilitated diffusion

• Concentration gradient: Relationship

  The greater the concentration difference, the faster the rate of facilitated diffusion
• Concentration gradient: Explanation

  • The greater the concentration difference, the faster the rate of facilitated diffusion, as particles are still moving down the concentration gradient
  • This is true until all the proteins are in use OR once equilibrium is reached, then the rate will level off/slow down
• Number of channel or carrier proteins: Relationship

  The greater the number of channel or carrier proteins in the plasma membrane, the faster the rate of facilitated diffusion
• Number of channel or carrier proteins: Explanation

  • Greater number = Faster rate
  • This is true up to a certain point, once all the proteins in the membrane are in use facilitated diffusion can't happen any faster even if you increase the concentration gradient. So, it becomes a limiting factor
• Is diffusion a passive or active process?

  Passive
• State the 4 factors that affect the rate of diffusion

  Temperature, Concentration gradient, Surface area, Membrane thickness
• Describe the role of a carrier protein

  Move large molecules across the membrane
• Which types of molecules would be transported using facilitated diffusion across the membrane?

  Large, ions or polar molecules
• Describe the role of a channel protein

  Form pores for charged particles to diffuse through
• Is facilitated diffusion a passive or active process?

  Passive