Final answer:
The cell membrane consists of a phospholipid bilayer, cholesterol, and embedded proteins, with carbohydrate chains present on its external surface. These components ensure its semipermeability and functionality in regulating cellular transport.
Step-by-step explanation:
The cell membrane, also referred to as the plasma membrane, is comprised primarily of a phospholipid bilayer, cholesterol, and a variety of proteins. The phospholipid bilayer forms the main structure of the membrane and consists of two layers of phospholipids, with hydrophobic tails facing inward and hydrophilic heads facing outward. Cholesterol molecules are interspersed within the bilayer, contributing to the fluidity and stability of the membrane.
The embedded proteins serve multiple functions, such as facilitating transport, acting as receptors, and participating in cell signaling and adhesion. On the external surface of the membrane, carbohydrate chains are often attached to both proteins and lipids, playing roles in cell recognition and protection. These components together ensure the membrane is semipermeable, carefully regulating what enters and exits the cell to maintain homeostasis.