What does the individual phospholipid do?

Individual phospholipids serve as key structural components of cell membranes, forming a bilayer that provides a barrier between the interior and exterior of the cell. Their hydrophilic (water-attracting) "heads" face outward, while the hydrophobic (water-repelling) "tails" face inward, creating a semi-permeable membrane. This arrangement allows for the selective passage of substances, facilitates cell signaling, and supports membrane fluidity, which is essential for various cellular functions. Additionally, phospholipids can participate in signaling pathways and assist in the formation of lipid rafts that organize membrane proteins.