Fatty acids consist of a carboxyl group (the hydrated form is called carboxylic acid) linked to a hydrophobic hydrocarbon tail. These molecules are used in the construction of cell membranes and fat. The hydrophobic nature of fatty acids is critically important to the normal function of the cell membrane since it prevents the passive entry of water and water-soluble molecules.
fatty acids are formed along the face of a geyser. Research has shown that some minerals can catalyze the stepwise formation of hydrocarbon tails of fatty acids from hydrogen and carbon monoxide gases -- gases that may have been released from hydrothermal vents. Fatty acids of various lengths are eventually released into the surrounding water.
http://physwww.mcmaster.ca/~higgsp/3D03 ... ghTemp.pdf
The problem with monomers is bad enough,but it is worse with polymers,e.g.,RNA and DNA (Lindahl1993),whose stability in the absence of efficient repair enzymes is too low to maintain genetic integrity iyperthermophiles. RNA and DNA are clearly too unstable to exist in a hot prebiotic environment.The existence of an RNA world with ribose appears to be incompatible with the idea of a hot origin of life.
The cell membrane is made of specific proteins.
Fatty acid binding proteins (FABPs) are members of a highly conserved family of proteins with the task of protecting a cell's delicate lipid balance.
To manufacture proteins, cells follow a very systematic procedure that first transcribes DNA into mRNA and then translates the mRNA into chains of amino acids. The amino acid chain then folds into specific proteins. So in order to sinthesize membrane proteins , you need a fully functioning cell nucleus, which in order to be able to function, needs the cell membrane, which protects it. That is a irreducible complex system.