Fatty Acid Synthesis Explained

Welcome to Biochemistry Essentials, where we make molecular life make sense. Today,

let’s build some fat — literally. Fatty acid synthesis is the process of making long-chain

fatty acids from smaller building blocks. It happens in the cytoplasm,

not the mitochondria — that’s already a key difference from beta-oxidation. Everything starts

with acetyl-CoA, which gets turned into malonyl-CoA by acetyl-CoA carboxylase, the rate-limiting

enzyme and main control point. Then, the fatty acid synthase complex steps in.

It links together one acetyl-CoA and several malonyl-CoA units, adding two carbons

at a time to the growing chain. Each cycle uses NADPH as the reducing power — think of