DESCRIBE THE STRUCTURAL COMPARTMENTATION OF MAMMALIAN CELLS
AND THE DIFFERING FUNCTIONS OF THESE COMPARTMENTS

Mammalian cells are classified as eukaryotic cells, as they contain organelles that are presented in all eukaryotic cells and with a membrane-bounded nucleus. Mammalian cells are one of four eukaryotic kingdoms, alongside Plantae, Fungi and Protista[1]. Eukaryotic cells are differ from prokaryotic cells by their larger in cell size, nucleus are membrane- bounded and complexity illustrated on their multicellular properties. Typically in all mammalian cells, one would expected to find organelles such as plasma membrane, nucleus, ribosomes, cytoplasm, mitochondria, Golgi apparatus, centrosome, centriole, endoplasmic reticulum, lysosome and peroxisome( illustrated on Figure 1 below).

All of these organelles presented on a mammalian cell are membrane- bounded and they each have specific roles in maintaining the cell's functionality.Different organelles in a mammalian cell perform unique role, many of which require specialized components for specific targets. The advantage of compartmentalization provides the most optimal micro-environments for these distinct processes, allowing damage limitation, minimizes non-specific interactions and consequently increased cellular efficiency. In general there are 4 main cellular compartments, they are: The nuclear compartment comprising the nucleus; The intercisternal space which comprises the space between the membranes of the endoplasmic reticulum (which is continuous with the nuclear envelope);Organelles and the cytosol[2]. For example, the genetic information known as the DNA is stored in the nucleus enclosed within a double nuclear membrane which regulates the proteins/transcription factors that activate/suppress gene expression. The aim of this essay will be focusing on the structural compartmentation and the unique function of different organelles in a mammalian cells.

Plasma membrane

Plasma membrane can be defined as a biological membrane or an outer membrane of a cell, which is composed of two layers of phospholipids and embedded with proteins. It is a thin semi permeable membrane layer, which surrounds the cytoplasm and other constituents of the cell[3].

There several important functions of this membrane:

1. It enclosed the cytoplasm within the cells, separating the content inside the cell apart from the fluid in the extracellular space

2. It regulates the entry and exist of particles/substance to the cell. Therefore, it plays an critical role in protecting the integrity of the interior of the cell by only approving several substances into the cells and keep other usefulness substances out of the cell.

3. It provides structural support for the cell, therefore helps in stabilizing and maintaining the overall structure of the cell.

4. Most of the membrane are composed of proteins and lipids. The role of lipids is to aid the membrane with their flexibility for cell movement. On the other hand, proteins help in monitoring and maintaining the cell's inner chemical climate and assist in the diffusion of molecules across the cell membrane[4].

5. The lipid bilayer is semi-permeable, there only specific molecules are allowed to diffuse across the membrane.

6. There are cell receptors located on the membrane surface, therefore giving them the ability to identify specific molecules or cells and allowing for cell to cell communication.

Cytoplasm

The cytoplasm is the ‘jelly-like’ region of the cell which consists of around 80% water [5]. It embodies a variety of different organelles which each perform specific tasks. Also within the cytoplasm is cytosol, where several chemical reactions of metabolism occur. The cytoplasm is the site of glycolysis, in which glycogen stores are broken down to form glucose; this is the initial stage of respiration.

Nucleus

The nucleus is the largest organelle in mammalian cells. It is