Figure 4.10 Protocells (A) In a series of experiments, Jack Szostak and his colleagues mixed fatty acid molecules in water. The molecules formed spherical structures called protocells, with water surrounded by bilayers of fatty acids. (B) A model of a protocell. A portion of the “membrane” has been cut away to reveal the inside of the protocell and the membrane’s bilayer structure. Nutrients and nucleotides pass through the “membrane” and enter the protocell, where they copy an already present RNA template. The new copies of RNA remain in the protocell.