• plasma-membrane
    A level biology,  A level biology,  Biochemistry,  Biology,  Cell biology,  O level biology

    Plasma membrane

    Delimiting membrane or boundary of all cells providing the characteristic shape to the cell. Structure ● Composed of approx. 7 nm thick phospholipid bilayer with hydrophilic heads facing outward from both sides into aqueous environment and hydrophobic tails facing inside the bilayer. ● A symmetrical the presence of proteins, floating in the bilayer imparts a fluid mosaic pattern which comprises of (a) Integral/Intrinsic proteins spanning through the lipid bilayer, protruding both extracellular and cytoplasmic sides of membrane. (b) Peripheral/Extrinsic proteins located on outside either extracellular or cytoplasmic surface. (c) Lipid anchored proteins covalently linked to a lipid molecule of bilayer but present outside to it. ● Some oligosaccharides are covalently…