Zelloberflächenmembran

Zelloberflächenmembran refers to the outer boundary of an animal cell, also known as the plasma membrane. It is a selectively permeable barrier that encloses the cell's cytoplasm and organelles. This membrane is primarily composed of a phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates. The phospholipid bilayer forms a continuous sheet that is impermeable to most water-soluble substances. Embedded within or attached to this bilayer are various proteins that perform diverse functions. These proteins can act as channels for transport, receptors for signaling molecules, enzymes, or structural components. Cholesterol molecules are interspersed within the lipid bilayer, contributing to membrane fluidity and stability. Carbohydrates are often found on the outer surface of the plasma membrane, attached to proteins (glycoproteins) or lipids (glycolipids), playing roles in cell recognition and adhesion. The cell surface membrane regulates the passage of substances into and out of the cell, maintains cell shape, and participates in cell-to-cell communication and interaction. Its dynamic nature allows for processes such as endocytosis and exocytosis, where the membrane engulfs or expels materials.