Facilitated Diffusion

What is Facilitated Diffusion?

Before we ask “what is facilitated diffusion” let’s try to define the individual words and see where that takes us. So, facilitation is to make something easy or relaxing, you must have heard guests getting facilitated on stage. This gesture is to make them feel relaxed or put them at ease in the new environment. Diffusion is the process of movement from a high concentration area to a low concentration area in any gaseous or liquid medium. So now let us mingle these two and understand the concept of facilitated diffusion in biology. So by fusing these two definitions we can describe facilitated diffusion as an assisted method in the transfer of particles through the concentration gradient. The assisting materials are mostly Transmembrane proteins that allow the easy transfer for only certain particles.


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Transmembrane Proteins

Earlier we mentioned certain proteins that facilitate other substances through the cell membrane, they are called transmembrane proteins. These proteins are spread across the wall of the cell and act as a bouncer to stop or allow specific types of substances.


There are two types of transmembrane proteins, which are basically what is used in facilitated diffusion:

  • Carrier Proteins: Carrier proteins as the name suggests carries vital substance into the cell. They are found on the cell membrane wall and work as a unidirectional protein. The glucose facilitated diffusion and red blood cells in our body are examples of facilitated diffusion incorporating this.

  • Channel Protein: These amino acid components are present in the membranes that act as a hydrophilic passageway for a particle of a specific size and shape. These transmembrane proteins if open all the time and allow entry of water-based molecules are called non-gated channel proteins and if they require a stimulus to open up they are called gated channel proteins. Muscles cells and nerve cells are examples of facilitated diffusion using channel proteins.


What Assists the Movement of Substances by Facilitated Diffusion in a System?

What is facilitated diffusion affected by that can either slow down or quicken up the process. The factors affecting facilitated diffusion are:

  • Temperature: Usually when the surrounding temperature of a cell is higher, the movement of the substance through the transmembrane proteins is faster. This is due to the greater energy levels exhibited.

  • Size: When it comes to cells, the intake substance varies in size. The larger sized particles will have a harder time getting through the transmembrane proteins than its smaller counterparts.

  • Concentration Amounts: The description of facilitated diffusion states the movement of particles from a higher concentration area to a low concentration area. Therefore, based on the concentration levels, the movement speed will vary.

  • The Number of Transmembrane Proteins: For a facilitated diffusion to take place there must be these so-called transmembrane proteins present according to what is facilitated diffusion is defined as. So, if there are many sites present the movement will also be greater and vice-versa.


What is a Facilitated Diffusion Example in Real Life?

There are plenty of examples of facilitated diffusion in the real world and for fact facilitated diffusion occurs probably every second in your body, it is just that you cannot notice them. There are plenty of tiny cells present within the body that function your body by generating energy. This energy can only be produced when the cells intake certain substances, but if any other type of substance is let inside it could damage the cell. 


Facilitated diffusion takes care of this situation where a certain substance can diffuse to any concentration gradient. Also, a certain type of protein called transmembrane greatly assists the cells in the intake and outtake of the substances.


What is facilitated diffusion in our body if you ask then the oxygen’s affinity towards red blood cells and the absorption of glucose molecules into cells are examples of facilitated diffusion in our bodies? We can also conclude that almost every living and non-living thing adapt facilitated diffusion when we define facilitated diffusion in biology.


Fun Facts

Diffusion and facilitated diffusion takes charge of how things are perceived in the world. Without it, there wouldn’t be smells coming out of a coffee cup or a piece of cake. 


Our bodies experience facilitated diffusion on a very minute and timely scale and yet even if one of these microscopic particles fails to process, it could lead to body malfunction and death.


Facilitate diffusion biology only consists of liquid and gas material. In solids, the molecules are rigidly packed and any kind of movement is extremely exhausting.

FAQ (Frequently Asked Questions)

1. What is the Importance of Facilitated Diffusion?

The surroundings of a cell are made up of different substances among which some can be harmful and others beneficial. For the cell to perform its daily tasks to keep itself-alive, these exchanges of substances are vital. What does facilitated diffusion mean to us? It could be the actual difference between life and death. There should be a way to filter out and let through substances at the same time. This is where facilitated diffusion comes into play. It allows the passage of hydrophilic substance into and out the membrane as shown in the facilitated diffusion diagram. Some of the passages present on the cell can be adjusted for a controlled movement through certain electrical and chemical signals. These passageways are called Transmembrane proteins.


In regular diffusion, these could be the passage of substance in the direction of the concentration gradient and does not require energy or ATP. Whereas with facilitated diffusion there is the choice of direction and also facilitated diffusion requires energy only in specific situations.

2. Does Facilitated Diffusion Occur in Solids?

As per the facilitated diffusion definition in biology takes place in two mediums, which are liquids and gasses. In a solid substance, however, facilitated diffusion definition does not occur in them. There must be movement present in the molecular level for diffusion to take place. A solid has its molecules tightly packed. 


A solid behaves like a solid because of the properties its molecules possess. The transfer of energy is only done through the vibration of the molecules. With that being said, there are exceptional cases in solids where the facilitated diffusion meaning does hold good. The mineral zeolites have larger sized molecules and due to this passage of substances through the interstitial space are possible. This was one of the examples of facilitated diffusion in solids. So in a solid substance, we can change how we define facilitated diffusion with some tweaking.