| The cell membrane
is not a wall or a skin or a sieve. It is an active and responsive part
of the cell; it decides what is inside and what is outside and what the
outside does to the inside. Cell membranes have 'faces' that enable
cells to recognize and influence one another. The membranes are also
communications systems. Things outside a cell do not necessarily act on
the cell interior by passing through the
membrane; they may simply change the membrane in some way that causes
the membrane, in turn, to make changes in the cell interior.
Biologist Daniel Mazia, quoted in Wilden 1972, p.xxxvii-xxxviii |