Fatty acids in water, given a level above a threshold concentration, spontaneously form a bilayer, a physically stable, low-energy configuration. This bilayer takes on a spherical shape. As such, this create a structure that envelopes water within its walls, a sort of vesicle. Again, this occurs as a direct result of the tendency of matter to organize itself into its most stable state. Supplying the vesicle with more fatty acids (in the form of organic compounds and the energy needed for the formation of said fatty acids) allows it to grow and divide. When the size of the bilayer increases by a fixed amount, its volume increases more than its surface area. And if the contents within the vesicle are not changed, the bilayer will naturally cave around its equator, resulting in a dumbbell-shaped vesicle, a first step towards cell division. Furthermore, hereditary material can become embedded in phospholipid bilayers, and with energy from hydrothermal vents, it is possible that this union of the two structures led to the first cell. Lastly, RNA within the cell, capable of replicating, would also split into both parts of the vesicle when a the bilayer begins to divide. This results in a cell with a membrane, hereditary material, and the ability to reproduce. The bilayer composed of fatty acids and the hereditary material are some of the most important structures needed for simple single-cellular life to have developed.
Lane, Nick. The Vital Question: Energy, Evolution, and the Origins of Complex Life. New York: W.W. Norton, 2015. Print.
- Ricardo Roche