".....the primary structure required by a primordial cell is a strong cell wall to protect it from the destructive thermal energy of free water (called the ‘molecular heat storm’). This has profound consequences....
Prokaryote cells are protected by a strong fibrous or paracrystalline capsule.
Eukaryote unicellular amoeba walls have a majority composition (~75%) of strong molecules (proteins and phosphoglycans) interwoven through their cytoplasmic membrane to strengthen it while maintaining flexibility so the amoeba can crawl in complex ways to find and ingest food particles and avoid predators.
Unicellular paramecia have a stiff, flexible, skin-like pellicle that protects the cytoplasmic membrane, which then overlays a polygonal network of fibers which anchor their body-covering cilia.
Multi-cellular plants, together with algae and fungi, have strong fibrous cell walls made from a variety of polysaccharides, including cellulose and chitin.
Multi-cellular animals house their cells within a flexible, fibrous, extra-cellular matrix, which is thickened on the outside to produce a leathery skin.
Unprotected animal cells in blood are kept safe through the blood serum being concentrated enough to neutralize the cell’s osmotic pressure gradient. If blood is diluted with too much water, the cells burst.
Prokaryotes must be primordial in naturalistic scenarios because they are much simpler than eukaryotes. 
The capsule which protects the prokaryote could be compared to something like a leather football. The ball has an impervious rubber bladder that holds the contents (compressed air) while an outer leather casing protects it from rupture when kicked. The prokaryote cell has an inner cytoplasmic membrane that guards the cell contents, and an outer capsule that protects it from rupture when exposed to the molecular heat storm.
One of many stumbling blocks encountered by Szostak’s team in constructing artificial cells is that the capsule holding the cell contents must expand as the cell grows, and it must divide when the cell divides. Synthetic capsules, like the plastic ones containing oral medications, are fixed in size—they do not grow or divide.
Q: So how does the prokaryote capsule do it?
A: The same way that most of the other cell components do it—by ‘self-templated self-assembly ’.
Fabrication of [molecular] architectures from top-down technology involve[s] precise growth techniques like molecular beam epitaxy, chemical vapor deposition and also involve[s] patterning techniques such as photo-lithography, particle beam lithography, scanning probe lithography, and nano imprint lithography.
While the above mentioned processes are laborious, time-
consuming, and costly, the‘bottom-up’ technology based on[the] self-assembly approach is the simplest, cost effective technique. Self-assembly is one of the most important ‘molecular engineering’strategies used in fabricating complex functional structures, from micro to the molecular levels, utilizing the advantage of self-interaction of molecules.Molecular self-assembly is a strategy for nanofabrication that involves designer molecules and supramolecular entitiesso that molecules naturally aggregate into specific desired structures.
As you can see from the quotation above, self-templated self-
assembly is not a naturally occurring phenomenon.
---It requires “designer molecules and supramolecular entities” which can self-assemble at the right place because “the target structures are selective with thermodynamically stable assembly”. That means the molecular machinery which accomplishes self-templated self-assembly is specially designed so that the statistical mechanics of physics and chemistry ensure that the single correct configuration is automatically chosen from the myriad wrong ones. Self-templated self-assembly is an ideal method of ‘bottom up’ construction, but it only works when the whole system is intelligently designed to function that way." CMI