In the opposite to fatty acid degradation, which is located within the mitochondria, de novo synthesis of fatty acids takes place within the cytosol.
The precursor of fatty acid synthesis is acetyl-CoA, that is transported out of the mitochondria into the cytosol via the citrate shuttle.
The NADPH necessary for fatty acid synthesis derives from the conversions of malic enzyme, glucose 6-P dehydrogenase, gluconate 6-P dehydrogenase and NADP-dependent isocitrate dehydrogenase.