Final answer:
The lipid bilayer self-seals a small tear due to its fluid nature, allowing lipid molecules to move and reorient themselves, with hydrophobic tails avoiding water and closing the gap. The membrane's mosaic structure and the presence of unsaturated fatty acids contribute to its fluidity and capacity to spontaneously repair.
Step-by-step explanation:
The lipid bilayer can self-seal a small tear due to the fluid nature of its components, primarily the hydrophobic tails of phospholipids. In the bilayer, these tails interact through dispersion forces that are weakened by the presence of unsaturated fatty acids, hence increasing fluidity. When a tear occurs, the surrounding lipid molecules can move and reorient themselves due to this fluidity, causing the hydrophobic tails to avoid water and close off the gap, effectively self-sealing the tear.
Another key factor is the mosaic characteristic of the membrane, which permits the proteins and lipids to float freely but loosely connected within the membrane. When disturbed, the flexible arrangement allows the components to fill in gaps spontaneously. Thus, when a tear happens, the immediate natural tendency for the hydrophobic tails to move away from the aqueous environment and the general fluidity of the membrane facilitates the closure of the tear.