What is citrate primarily used for in biosynthesis?

Citrate plays a crucial role in biosynthesis, particularly in the synthesis of fatty acids and sterols. When citrate is produced in the citric acid cycle, it can exit the mitochondria into the cytosol, where it is converted by the enzyme ATP citrolyase into acetyl-CoA and oxaloacetate. The acetyl-CoA generated from this process is a key building block for the synthesis of fatty acids and sterols.

Fatty acids are essential components of cell membranes and are used to store energy, while sterols, such as cholesterol, are vital for maintaining membrane structure and serving as precursors for steroid hormones. Thus, citrate effectively links energy production within the mitochondria to the biosynthetic pathways occurring in the cytosol, facilitating the creation of necessary lipids.

The connection of citrate to energy availability and its role in generating acetyl-CoA for lipid synthesis underscores its importance in metabolic processes involved in the biosynthesis of fatty acids and sterols.