plasma membrane
biological membrane that separates the interior of a cell from its outside environment
passive transport
membrane transport that occurs down an electrochemical gradient and does not require energy
sarcolemma
the outer membrane of a muscle cell, consisting of the plasma membrane, a covering basement membrane (about 100 nm thick and sometimes common to more than one fiber), and the associated loose network of collagen fibers
bacterial outer membrane
plasma membrane found in gram-negative bacteria