The plasma membrane is a critical cellular structure that acts as a selective
barrier, controlling the movement of molecules in and out of the cell while enabling
communication with the external environment. This chapter provides an in-depth
exploration of the plasma membrane, beginning with its structure and the fluid-mosaic
model, which describes the dynamic organization of lipids, proteins, and
carbohydrates. It then examines the various functions of the membrane, including
maintaining cellular integrity, supporting signal transduction, and regulating the
movement of substances through mechanisms like passive diffusion, facilitated
diffusion, active transport, and group translocation. Key transport proteins such as
glucose transporters and ion channels are discussed in detail, highlighting their roles in
maintaining cellular homeostasis. The chapter also addresses the pathological
significance of plasma membrane dysfunction, linking abnormalities to diseases such
as hypertension, sphingolipid-related disorders, and neuronal vulnerabilities. Further, it
explores the role of the plasma membrane in neurotrophic signaling and insulin
regulation. Finally, recent advances in therapeutic approaches, including CAR-T cell
therapy and liposomal drug delivery systems, are examined for their potential in
disease treatment.
Keywords: Active Transport, Aquaporin, Bilayer, Diffusion, Endocytosis, Exocytosis, Facilitated Diffusion, Insulin, Lipid Raft, Membrane Potential, Neurotransmitter, Phospholipid, Potassium Channel, Sphingolipidoses.
