Lipiddobbeltlaget

Lipiddobbeltlaget, also known as the lipid bilayer, is a fundamental structure that forms the basis of all biological membranes. It consists of two layers of phospholipid molecules. Each phospholipid molecule has a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails. In an aqueous environment, these molecules spontaneously arrange themselves into a bilayer with the hydrophilic heads facing outwards towards the watery cytoplasm and extracellular fluid, and the hydrophobic tails facing inwards, shielded from water. This arrangement creates a stable barrier that separates the cell's internal environment from its external surroundings. The lipid bilayer is not rigid; it is fluid, allowing for the movement of lipids and embedded proteins within the membrane. This fluidity is crucial for various cellular functions, including cell signaling, transport, and cell division. Embedded within or attached to this lipid bilayer are various proteins that perform specific functions, such as acting as channels for molecule transport, receptors for signaling molecules, or enzymes. The selective permeability of the lipid bilayer, along with the functions of these membrane proteins, dictates what can enter and leave the cell.