ABSTRACT
This chapter reviews some basic physiological and biophysical
aspects of the plasma membrane. Seen as a semipermeable barrier,
this particular wall is able to allow diffusional flows of ions and molecules through passive and active transport. Because of its
character of semipermeable barrier, it gives rise to the separation
of charges (cations and anions) along its entire thickness and
molecules at the intracellular and extracellular side. This generates
electrochemical gradients used by the cell as a driving force.
The chapter also gives emphasis on transmembrane proteins (ion
channels) andmechanisms involved in both release (exocytosis) and
uptake of molecules (endocytosis). These mechanisms are useful
for cellular communication and internalization of endogenous and
exogenousmolecules, aswell as particles present in the extracellular
space.
