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Diffusion vs Active Transport

Diffusion

• 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.

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▶️ Diffusion: Types & Factors Affecting Rate of Diffusion