Diffusion vs Facilitated Diffusion
Chemists and biologists alike are dedicated to observing the behavior and movement of particles through different areas of concentration. Chemists may monitor the movement of particles from one mixture to another while biologists may study how these particles go in and out of the cells through the cell membrane. It is during these quests that these scientists encounter terms such as diffusion and facilitated diffusion.
Diffusion refers to a passive transport of particles brought about by several factors such as thermal or random movements of molecules. The rate at which one particle is being transported from one gradient to another depends on the concentration of mixtures, size of molecules involved, the distance covered by the molecule, external temperature, solubility of the molecule, and the surface area of the membrane over which the molecule is expected to work.
This mechanism may as well be referred to as simple diffusion. In simpler explanations of experts, simple diffusion occurs when molecules move from an area with higher concentration down to the area with lower concentration. This being a natural occurrence, there is no input of energy involved in simple diffusion.
In cellular activities, for example, simple diffusion can be observed when small molecules enter or exit the cell through the lipid bilayer of the cell membrane. Since the mechanism is considered passive, the crossing of the molecules through the cell membrane does not involve the exertion of any energy or special attention from the cell.
This is because in simple diffusion, small non-polar molecules pass through the cell membrane – meaning, a hydrophobic molecule, for example, can pass freely through the hydrophobic region of the membrane without experiencing rejection because of their similar components. Simple passive diffusion does not involve protein carriers.
Hydrophilic molecules, on the other hand, cannot be suitable for simple diffusion because they will be rejected as they pass through the hydrophobic region of the membrane. In such cases, the transportation of particles will only be possible through facilitated simple diffusion.
Facilitated diffusion can be said to be an example of a passive transport or molecule movement from one gradient to another. Similar to simple diffusion, facilitated diffusion may still refer to the movement of molecules. Nonetheless, this type of transport is highly dependent on protein carriers which operate on a bind, flip, and release mechanism. The molecule would then move along with these carriers.
Unlike simple diffusion, saturation happens in this type of transportation especially when there is not enough carriers available to facilitate all the solute molecules. Thus, energy is exerted in the transport, and the rate of movement is at its maximum.
In most cases, molecules need an ion pump during facilitated diffusions. The ions work as the alternative for the protein carriers in different conditions and lab experiments.
The difference between simple diffusion and facilitated diffusion may as well be drawn in reference to the change in the concentration of gradients where the molecules move from and into.
Simple diffusion involves the movement of particles or molecules from an area of higher concentration to lower concentration. Naturally, the particles can penetrate into gradients with lesser particles in order to attain balance between the gradients. Osmosis is a perfect example for this molecular activity.
On the other hand, when laboratory experiments require the movement of molecules from area of lower concentration to a gradient with a higher concentration, facilitated diffusion may be utilized. The scientists may inject carriers or facilitators in the gradients in order for the molecules to be able to penetrate an area with condensed particles such as in reverse osmosis.
Summary:
1.Facilitated diffusion and simple diffusion refer to the movement of molecules from one gradient to another.
2.Facilitated diffusion is an example of a passive, simple diffusion.
3.Simple diffusion does not require protein carriers or exertion of energy during cellular activity while facilitated diffusion needs protein carriers or ion pumps for transportation.
4.Hydrophobic molecules can have simple diffusion while hydrophilic molecules require facilitated diffusion during cellular activity.