Sample Essay on Cellular Membrane

Cellular Membrane

The eukaryotic cell has several parts, which perform a variety of function within and around the cells. Of key interest is the cell membrane, which performs the functions of the cell membranes and cell wall available in the plant cells. As such, the main function of this part is to percolate the kinds of materials that get into and out of the cells. Based on its structural make-up and the functional specifications, the cell membrane of the eukaryotic cell is described as semi-permeable membrane. The major components of the cell membrane include structural and functional proteins, lipids, and phosphorous-based materials within the membrane. The orientation of the layers includes the hydrophilic and hydrophobic ends of the phospholipids bilayer in such ways that the lipids, which are non-polar, end, are within the membrane while the phosphor groups are on the outer portion. Along the spread of the membrane, there are a number of proteins that participate in the structural and functional orientation of the membrane, as well as the glycoprotein (

Diffusion and Passive Transport

The movement of particles or materials from regions of high concentration to regions of low concentration is known as the process of diffusion. The cell membrane allows materials to get into the cell through the process of diffusion and succeeds to provide the organelles and cellular processes with the nutrients and materials needed. This process occurs when ions of minute sizes are more on the outside of the cell while depleted within the cell. Through the process of diffusion, the materials will move from these regions of greater concentration to the regions of lower concentration within the cells (

Passive diffusion is a process that involves the movement of materials into the cell by the help of transmembrane proteins, due to their unique features and properties. These proteins allow particular materials possessing corresponding features to pass through them into the cell. It allows the materials to bind to the proteins, and through passive diffusion based on concentration differences, to move into the cells and reach the target organelles for utilization. Such proteins that act as mediators in the passive diffusion are known as the passive diffusion proteins.

The Role of ATP in Active Transport

At any given time, despite the lack of positive gradient in terms of concentration outside and inside the cell, some materials are needed by the cell for the purposes of performing some cellular functions. When such a need arises, there is a need for the materials to be pumped into the cells to replenish the required nutrients or pumped out of the cell in order to remove wastes from the inside of the cell to the interstitial space for excretion. This process requires the use of energy and this is where ATP comes in. Also known as Adenosine triphosphate, ATP is a high-energy molecule that provides energy for the many cellular processes. The mechanism of production of energy comes about as when one of the high-energy bonds linking a phosphate group to the others is broken to release energy. When this phosphate group is removed, the result is production of energy while the molecule of ATP is reduced to ADP, which is adenosine diphosphate. The energy released here is used to pump material in or out of the cell (

Endocytosis and Exocytosis

            Particular cell types falling in the category of eukaryotic cells have characteristics or need based functionalities that require processes related to phagocytosis. Endocytosis is the process by which a cell will acquire nutrient or gain access to a particle through engulfing it in its cell membrane, introducing it into the cytoplasm and exposing it to the target organelles. This process occurs when the cell membrane come into contact with the material, surrounds it, and creates a split that allows it into the cell. Exocytosis, on the other hand, is the process through which a cell releases or removes the materials from within the cell to the interstitial space through the reverse process of endocytosis. Both  processes can be performed by the cell and organelle membrane through the formation of transitional vesicles. The website supporting these assertions is

Works cited structure of eukaryotic cells and functions. 2 january 2014. 4 november 2014 <>.