English: Drawing 1. Hypothesis of the mechanical origin of chirality in the phospholipids. here is treated the positioning of ethanolamine relatively to the phosphate. Its displacement towards the phosphate to establish hydrogen bonding causes a rotation. This hypothesis states that the clockwise rotation and positioning in single file of the phospholipid molecules, (RG box), results in bringing closer the two leaflets of the liposome, increasing its cohesion. In this configuration the serine chirality would be L, because its carboxyl can not be put under the reference plane defined by the phosphate (see caption in the drawing) and then would be near the carboxyl of two fatty acid molecules neighbors.