Fosfólípída

Fosfólípída are a class of lipids that are a major component of all cell membranes. They are amphipathic, meaning they have both a hydrophilic (water-attracting) head and a hydrophobic (water-repelling) tail. This dual nature allows them to form a bilayer structure in aqueous environments, with the hydrophilic heads facing outwards towards the water and the hydrophobic tails facing inwards, away from the water.

The basic structure of a fosfólípída molecule consists of a glycerol backbone, two fatty acid chains attached to the glycerol, and a phosphate group. The phosphate group is usually linked to another small molecule, such as choline or ethanolamine, which further contributes to the hydrophilic nature of the head. The specific type of fatty acid chains and the molecule attached to the phosphate group can vary, leading to different types of fosfólípída.

In cell membranes, the fosfólípída bilayer acts as a barrier, controlling the passage of substances into and out of the cell. Proteins are often embedded within or attached to this bilayer, performing various functions such as transport, signaling, and enzymatic activity. The fluidity of the membrane, which is crucial for many cellular processes, is also influenced by the composition and arrangement of fosfólípída. Beyond their structural role, fosfólípída also play a part in cell signaling and can act as precursors for other important molecules.