Explain Why All Living Cells Have A Membrane Separation Of Cell Contents From The Cell Environment

All living cells have a membrane separating the cell contents from the cells environment. This membrane allows the cell to maintain an internal environment that is suitable for the survival of the cell. Since cells exist in some external environment, it is necessary that some form of interaction occur between the cell and its external environment. The cell membrane functions as a barrier to the unrestricted movement of substances between the intracellular region and the environment of the cell. This barrier is selectively permeable to certain materials in the fluids surrounding the cells, allowing these materials to cross the membrane relatively unhindered while preventing the movement of
others.