Membrani
Membrani, or membranes, are lipid bilayer structures that enclose cells and organelles, forming selective barriers that regulate exchange with the environment and internal compartments. They define the boundaries of life and organize the chemical reactions that sustain it.
They are primarily composed of phospholipids arranged in a bilayer with hydrophobic tails hidden from water
The plasma membrane is the best-known example, but every organelle in a eukaryotic cell has its own
Membranes regulate transport through diffusion, channels, carriers, and pumps, and facilitate active transport that requires energy.