The Plasma Membrane - Essay Sample

Introduction

The plasma membrane is the outer membrane of a cell and is composed of four primary components. These components are phospholipids, proteins, carbohydrates, and cholesterol. The plasma membrane protects the prokaryotic and eukaryotic cells as it creates the boundary between cytoplasm and the external environment. Its characteristic of permeability controls the movement of substances into and out of the cell. Therefore, this essay seeks to discuss the structure of well-labeled plasma membrane structure and the functions of each component in the plasma membrane.

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Components and its Functions

First, the plasma membrane is composed of lipids and cholesterol. According to Phillips and Voeltz (2016), there are two layers of phospholipids made of glycerol, fatty acids, and phosphate linked head group. The bilayer o phospholipids make up the vital fabric in the plasma membrane. They are amphipathic thus suitable for its function of bilayer; they have the hydrophilic and hydrophobic regions which assist in forming a stable barrier region between aqueous sections. Hydrophilic region is the water-loving region that contacts the watery fluids both inside and outside the membrane. Furthermore, it readily forms electrostatic interactions with the phospholipids heads. On the other hand, hydrophobic is the water fearing part whereby the fatty acids tails and has reduced contact with water thus forming a barrier between the cell and the surrounding environment. Additionally, there is also another lipid referred to as cholesterol, and it constitutes for carbon rings found along phospholipids in the core of the plasma membrane. It maintains the fluidity of the membrane. Besides, it is placed between the tails of hydrophobic in membrane phospholipids.

Secondly is the protein component. It constitutes the internal and peripheral membrane proteins. The integral membrane has one hydrophobic region; hence they stick into the hydrophobic core of the phospholipid layer; perhaps, it is integrated into the membrane. On the other hand, there is the peripheral membrane protein that is located inside and outside the membrane surface. Peripheral membranes proteins are loosely attached to the hydrophobic core membrane; hence do not stick into the hydrophobic core of the phospholipid layer. Proteins found in plasma membrane have various functions; they act as pumps, channels, enzymes as well as receptors. Besides, glycoproteins are essential because they are used for cell recognition. Moreover, glycolipids along with sugar chains are attached to phospholipids which are necessary for creating partially permeability.

There are carbohydrates which are another component of the plasma membrane. They are found on the surface of the membrane and in most cases, they are attached to either protein forming glycoproteins or to lipids forming glycolipids as stated by Rega (2018). Carbohydrates also form cellular markers that are essential in human bodies. They are vital in human immune system because it assists the immune cells in differentiating between the body cells which they should protect and the foreign cells which they should attack. Furthermore, glycolipids help in determining one's blood group at the surface of red blood cells and on hormones during embryonic development, they act as receptors, and this will aid in classifying blood groups which are crucial during a blood transfusion.

Conclusion

In conclusion, the plasma membrane is essential in the human body and plays a vital role. Its ability to being permeable regulates the movement of substances in and out of the layer. Lipids assist in giving the membranes their flexibility while proteins help in monitoring molecules transfer in and out of the cell. Hence plasma membrane needs attention because it protects the inner contents of the cell.

Reference

Phillips, M. J., & Voeltz, G. K. (2016). Structure and function of ER membrane contact sites with other organelles. Nature Reviews Molecular Cell Biology, 17(2), 69.

Rega, A. F. (2018). The Ca2+ Pump of Plasma Membranes: 0. CRC press.