Lípíðalög

Lípíðalög, often translated as lipid bilayers, are fundamental structures in cell biology. They form the outer boundary of cells and the membranes of internal organelles. A lipid bilayer consists of two layers of phospholipid molecules. Each phospholipid molecule has a hydrophilic head, which is attracted to water, and a hydrophobic tail, which repels water. In an aqueous environment, these molecules spontaneously arrange themselves into a bilayer with the hydrophilic heads facing outwards, towards the water, and the hydrophobic tails facing inwards, away from the water.

This arrangement creates a stable barrier that is selectively permeable. While water and small, nonpolar molecules can pass through relatively easily, larger or charged molecules require specific transport proteins to cross the membrane. The fluidity of the lipid bilayer is also crucial for cell function. Proteins embedded within or attached to the bilayer can move laterally, allowing for cell signaling and transport processes. This dynamic nature is essential for maintaining cell integrity and carrying out various cellular activities. The composition of lipids within the bilayer can vary, influencing its fluidity and the types of proteins it can accommodate, thus tailoring membrane properties to specific cellular needs.