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
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
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
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