Movement of Molecules: Passive Transport, Simple Diffusion, Facilitated Diffusion

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Passive Transport

  • In Passive Transport, the transportation of molecules across the membrane is using a concentration gradient.

  • Cellular energy is not required.

  • The movement of biochemical is from higher to the lower concentration.

  • Natural entropy is used for movement form higher to the lower concentration.

  • At equilibrium there is no net transport of molecules.

  • Using this process all the waste molecules using water and carbon dioxide get separated.

  • This process occurs in the kidneys and the liver including the alveoli of the lungs during the exchange oxygen and carbon dioxide.

  • Some of the examples of passive transport are Osmosis, diffusion and facilitated diffusion.

Passive Transport

Passive Transport

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Types of Passive Transport

Simple Diffusion

  • There is a net movement of atoms, ions, and molecules.

  • Movement is from a region of higher concentration to a region of lower concentration.

  • Driven by a gradient in concentration.

  • Simple diffusion is used by many non-polar molecules.

Simple Diffusion

Simple Diffusion

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Simple Diffusion

Simple Diffusion

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Facilitated Diffusion

  • Also known as facilitated transport or passive-mediated transport.

  • Involves process of spontaneous passive transport.

  • Doesn’t directly require chemical energy from ATP hydrolysis.

  • The transportation is based on molecular binding.

Facilitated Diffusion

Facilitated Diffusion

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Facilitated Diffusion

Facilitated Diffusion

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Osmosis

  • Transportation of water and other molecules or substance.

  • The transportation takes place through the selectively permeable cell membrane.

  • Factors affecting this transportation:

    • Cell having less negative water potential.

    • Soluble potential of a molecule.

    • Pressure potential of a cell membrane.

Transportation of water and other molecules

Transportation of Water and Other Molecules

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