Lipid metabolism sub-model. Schematic drawing of lipid metabolism. Cytosolic AcCoA entering the lipid metabolism compartment from the intermediate metabolism is used for FA synthesis. FAs are either broken down, leading to AcCoA in the mitochondria, which fuels the TCA cycle, or are used for TAG synthesis, thereby increasing the body weight. ATP inhibits TAG degradation and FA breakdown. TAG deposit levels inhibit (⊗) TAG synthesis, and citrate levels in the mitochondria promote () FA synthesis.