sejtmembraánba

Sejtmembraánba, often translated as cell membrane, is a biological membrane that surrounds the cytoplasm of a cell. It is a selectively permeable barrier that controls the movement of substances into and out of the cell. The cell membrane is composed primarily of a phospholipid bilayer, with various proteins embedded within or attached to it. These proteins play crucial roles in cell signaling, transport of molecules, and cell adhesion. The structure of the cell membrane is often described by the fluid mosaic model, which highlights its dynamic and fluid nature, with phospholipids and proteins able to move laterally within the membrane. The inner and outer surfaces of the cell membrane can have different compositions and functions, and it plays a vital role in maintaining the cell's internal environment, known as homeostasis. In eukaryotic cells, the cell membrane also encloses organelles within the cytoplasm, such as the nucleus, mitochondria, and endoplasmic reticulum, each surrounded by their own membranes. The cell membrane is essential for cell survival, growth, and interaction with its surroundings.