Diffusion

Cards (9)

  • Diffusion is the net movement of molecules or ions from a region of high concentration to low concentration until an equilibrium is reached
  • Diffusion is a passive process so doesn't require extra input of energy
  • Increase rate of diffusion by
    • increasing temperature
    • higher concentration gradient
    • higher surface area
    • shorter diffusion pathway
  • Rate of diffusion is calculated by surface area x concentration gradient all divided by diffusion distance
  • Other factors that affect rate of diffusion
    • molecular mass/size
    • charge/polarity
  • Water-filled channel proteins can be described as aquaporins
  • Facilitated diffusion is the movement of molecules across a membrane with the help of a protein
  • Channel proteins increase the permeability of the plasma membrane to water and other molecules
  • Carrier proteins changes shape and rotates through the membrane and deposits the molecule on the other side