This means that the cell is the fundamental unit from which the biological hierarchy is fashioned. Whatever its particular forms, however it behaves, the cell is the microscopic package that contains all the parts necessary to survive in a constantly changing environment. One of the most striking properties of a cell is its complex organization. It is in the cell where simple inorganic molecules as well as those complex organic ones we've studied take on the special characteristics of life. The biochemical activity of each cell is critical to the maintenance of cellular homeostasis.
Cells are amazingly diverse in shape, size, and function.
Our human bodies contain trillions of cells and some 200 different types of cells. A cell's shape reflects its function. These tightly fitting cells form a living barrier that protects underlying tissues from bacterial invasion. Although no one cell type is exactly like all others, eukaryotic cells in most existing species, do have the same basic parts and each part has an important function for the cell's survival. All cell components will need to be included and identified.