top of page

📚 > Physiology > General Physiology > Transport of Substances Through Cell Membrane_>

Diffusion vs Active Transport


  • Fundamentally, diffusion is random movement of molecules.

  • During diffusion, there is a net movement of a substance down its electrochemical gradient.

  • Occurs through:

  • Lipid bilayer: Lipid soluble substances

  • Pores or channels: Water and water-soluble substances

  • Driven by electrochemical gradient. No extra energy is required from external sources.

Active Transport

  • Molecules are actively transported against electrochemical gradient.

  • Occurs through transport proteins.

  • Requires energy from external sources e.g. ATPs.


Next >>

▶️ Diffusion: Types & Factors Affecting Rate of Diffusion
bottom of page