A composite cell is any one of a collection of different types of cells that all have the same general chemical makeup that perform the same functions. Because many cells are very similar to one another in these ways, it is possible to generalize them all as composite cells.
Cell theory states that many cells are chemically similar to one another and have the same basic elemental composition: carbon, hydrogen, nitrogen, oxygen and trace amounts of other elements. Many cells also contain the same structures, such as the nucleus, cytoplasm and cell membrane. In all composite cells, these structures have similar shapes and perform the same functions, regardless of where in the body the cell is found. Because there are so many similarities between these cells, they can be grouped together and called "composite cells" or "generalized cells."
Although "composite cell" does not refer to a specific type of cell, it can be used as a shorthand to describe the behavior and components of many different classes of cells at once. The specific organelles inside of the cytoplasm of composite cells may vary from one another. The term "composite cells" is best used when describing cellular properties that are true for a multitude of cells all over the body or between different species.