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What Does Cholesterol Do In The Cell Membrane
Cholesterol is an organic substance that belongs to the steroid family. This waxy substance is extremely important in order for the body to carry out several functions such as producing steroid hormones, vitamin D, and other compounds from which the body synthesizes bile acids.
Due to the above-mentioned reasons, the body has the capacity to produce cholesterol – this process occurs in the liver to be more precise – however, this is not the only source of cholesterol as it can also be found in animal foods like egg yolks, milk, cheese, and meat.
Furthermore, cholesterol is present in every cell of the animal kingdom (even in humans) and it is pivotal for the continuous functionality of such cells. Interested to know how this process works? Keep on reading this article to understand what does cholesterol do in the cell membrane.
Where is Cholesterol Found in the Cell Membrane?
The cell membrane, also known as the plasma membrane, is a semipermeable lipid bilayer whose function is to separate the interior of the cell from its outside surroundings. This thin membrane surrounds every living cell.
The cell membrane is composed essentially of fatty-acid lipids, but it also contains proteins and carbohydrates.
Lipids are the predominant component of the membrane cell and there are three types of them, phospholipids, glycolipids, and sterols (mainly cholesterol). Their distinguishing characteristic is that they have the capacity to dissolve in organic solvents and part of them is attracted and soluble in water.
In the cell membrane, cholesterol is distributed in both the inner and outer leaflets. Cholesterol acts by inserting itself into the phospholipid bilayer with its polar hydroxyl group close to the phospholipid head groups.
What Does Cholesterol Do In The Cell Membrane – Cell Plasma
You have probably heard bad things about cholesterol, however cholesterol is not completely bad as you might have been led to believe as it is also essential for human physiology and cell functions. In the plasma membrane, cholesterol plays a huge role in its functionality.
Cholesterol represents around 25-30% of the plasma membrane (the most abundant substance) and due to its chemical structure, it has the capacity to fit in spaces in the middle of the phospholipids and prevent the diffusion across the membrane of water-soluble molecules, thus reducing the permeability of the membrane.
In addition, cholesterol has the capacity to affect membrane fluidity by increasing the temperature range in which the plasma membrane can continue to function, keep on reading to understand more about this phenomenon.
How Does Cholesterol Affects Membrane Fluidity?
There are a number of factors that can modify membrane fluidity; however, cholesterol is the most remarkable factor as it has the capacity to both increase and decrease membrane fluidity, depending on the temperature.
When the temperature rises cholesterol diminishes membrane fluidity by pulling phospholipids together and increasing intermolecular forces. On the other hand, when the temperature drops, cholesterol increases fluidity by keeping phospholipids from packing together.
In this manner cholesterol has the capacity to act as a buffer for the cell membrane, helping it keep fluidity even when the temperature rises or drops. In other words, cholesterol helps to expand the range of temperature in which the cell membrane is fluid and consequently, functional.
What Would Happen if There Was No Cholesterol in the Cell Membrane?
Wondering about what would happen in cell membrane if there was no cholesterol? So here is the deal, remember that one of the functions of the cell membrane is to control what substances get in and out of the cell, it acts as a barrier.
Cholesterol is very helpful with that as it has the ability to fit between the phospholipids, holding them together so that unwanted substances cannot cross the membrane.
On the contrary, cholesterol also helps by not letting phospholipids become too tight and restrict the passage of important substances. As if that was not enough, cholesterol acts by helping the bilayer keep fluid under different temperatures.
Without the presence of cholesterol, phospholipids could either separate from each other, leaving huge gaps and thus permitting the passage of unwanted substances, or get closer together and prevent the passage of important substances such as gases or other small molecules.
All of these processes are extremely important in keeping the body functioning, for instance, there is a list of diseases associated with problems in the phospholipid bilayer, Alzheimer being one of them.
One of the explanations is that this disease acts by forming a plaque that sticks to the phospholipid bilayer in the neurons of the brain, consequently causing the neuron’s death which could explain the loss of memory, a common symptom of Alzheimer’s disease.
What Does Cholesterol Do In The Cell Membrane Conclusion
After reading this article, it should be clear that cholesterol is a vital substance in any animal’s cells.
Firstly, it is essential to completing many bodily functions, secondly, it also plays a huge role in various metabolic pathways, and thirdly, it is fundamental for the functionality of the cell membrane.
The role of cholesterol in the cell membrane is vital. Cholesterol has the capacity to affect membrane fluidity not only by increasing the temperature range in which the cell membrane can continue to function, but it also serves as a barrier, as due to its chemical structure it can fit in spaces between phospholipids, preventing water-soluble substances from diffusing across the membrane.
Simply put, life would not be possible without cholesterol.