Amphipathic lipids -membranes

Membranes are a thin layer of lipid molecules which extend across the cell surface

of every living cell. They protect cells from potential pathogens, as well as

Store and release molecules such as hormones and nutrients

The membranes in our bodies are extremely important because they need to be able to absorb chemicals, either through diffusion or passive transport. That is how cells communicate with one another and how they receive their nutrients; those two were the functional roles of membrane lipids.

What are Amphipathic lipids?

An amphipathic lipid is a molecule with hydrophilic, polar heads and hydrophobic, non-polar tails. Furthermore, an amphipathic lipid is a type of fat that helps to form cell membranes.

This article will highlight the concept of Amphipathic lipids -membranes along with its application and importance. 

Amphipathic Lipids: Membranes

Every living organism needs a cell membrane to control what goes in and out of the cell. This barrier regulates what is eaten by cells and protects them from harmful substances that cannot get past it. A lipid is a type of molecule that helps form cell membranes. The term “lipid” refers to the fatty portion of what are known as lipids. The most common lipids are triglycerides, phospholipids, and cholesterol. The dynamic amphipathic lipid is made up of hydrophilic heads joined by sterically-invariant linkers to non-polar tails, which allows the lipid to function as both an amphipathic and a lipophilic compound. There are two different types of amphipathic lipids: neutral and acidic. Each type has an acid group (a pK b of 3) that makes it acidic at physiologic pH. The neutral amphipathic lipid has a hydrophilic head and a non-polar, sterically-variant tail. The neutral amphipathic lipid, which includes synthetic polymers and natural phospholipids, is the most versatile of two types of amphipathic lipids because it can be used in both the hydrophobic and hydrophilic environments of biological membranes.

Biological membranes are composed of lipids that are amphiphilic, meaning they can dissolve in water as well as oil (grease). The most common lipids found in biological membranes are phospholipids and glycolipids.

Role of Amphipathic Lipids:

Lipids are important for functions such as neutralizing acidic environments and preventing the permeability of water across a cell membrane. For example, when you have a cut on your skin and it starts to bleed, the blood plasma will start to leak out of the cut. In order to stop this from happening, there needs to be an amphipathic lipid present within the wound. The lipid will take on the role of preventing water from entering the wound too fast by sticking to the walls (hydrophilic end) and also sticking to any free proteins that are still within the wound as well (hydrophobic end).

Importance of Amphipathic Lipids:

Membranes need to be able to take up molecules that are either freely diffusible (like sugars, amino acids and glycerol) or poorly diffusible (such as toxins and other antimicrobial molecules). In the case of water-soluble ions, membranes are able to passively transport them across the membrane. In other cases such as toxins and antibiotics, the molecule needs to be actively taken in by the cell. Amphipathic lipids can bind these compounds by forming a lipid bilayer, thereby stabilizing them within the membrane.

Types of Amphipathic Lipids:

There are two types of amphipathic lipids: neutral and acidic lipids.

1. Neutral Amphipathic Lipid

The neutral amphipathic lipid is the most common form of lipid as it is used in biological membranes. These lipids are also a type of natural membrane protein that provide protection and transport for human cells. Neutral amphipathic lipids consist of the polar heads and nonpolar tails, which allows for them to be able to travel within both hydrophilic and hydrophobic environments. However, a few types of neutral amphipathic lipids can only function in one environment, such as within biological membranes or inside a cell cytosol.

2. Acidic Amphipathic Lipid

The acidic amphipathic lipids are more capable at transporting molecules and ions in a passive manner than neutral amphipathic lipids and they are also able to form stable complexes with many toxins and molecules.  The acidic amphipathic lipid is the same as a neutral amphipathic lipid, except that it is made up of an ionized acid group. This allows the lipids to act as detergents, which are capable of breaking down fats and fats in membranes.

Conclusion:

Amphipathic lipids are essential for a cellular membrane to properly perform its functions. For example, the lipid bilayer within biological membranes is able to passively transport molecules and ions that are free diffusible, such as sugars and amino acids, but it actively transports ionized molecules that have an ionized group. This can also be seen in cells with regards to toxins and antibiotics. Amphipathic lipids are able to bind these types of active molecules by forming a lipid bilayer, thereby stabilizing them within the cell membrane by enhancing diffusion of ionized substances across the membrane.