Interior Cell Membranes. It is the thick and rigid structure with a fixed shape. THE LIPID BILAYER The lipid bilayerhas been firmly established as the universal basis for cell-membrane structure.
The bilayer membrane that separates the interior of a cell from the surrounding fluids is largely composed of phospholipids but it incorporates many other components such as cholesterol that contribute to its structural integrity. The membrane of an internal vesicle fuses with the external plasma membrane and the internal contents of the vesicle are expelled to the outside. Thus the membrane surfaces that face the interior and exterior of the cell are hydrophilic.
The plasma membrane separates internal metabolic events from the external environment and controls the movement of materials into and out of the cellThe plasma membrane is a double phospholipid membrane lipid bilayer with the nonpolar hydrophobic tails pointing toward the inside of the membrane and the polar hydrophilic heads forming the inner and outer faces of the.
The membrane of the vesicle then becomes part of the plasma membrane. In plant cells the membrane encapsulates the protoplasm. The heads which form the outer and inner linings are hydrophilic water loving while the tails that face the interior of the cell membrane are hydrophobic water fearing. This phospholipid molecule is composed of a hydrophilic head and two hydrophobic tails.