Final answer:
Triglycerides are synthesized in the smooth endoplasmic reticulum of cells, a process that involves elongation of fatty acids utilizing enzymes called elongases.
Step-by-step explanation:
Triglycerides are synthesized primarily in the smooth endoplasmic reticulum (SER) of cells. The SER is involved in the biosynthesis of lipids, carbohydrate metabolism, and the detoxification of toxic compounds. The process of triglyceride formation, also known as lipogenesis, includes the elongation of fatty acids which occurs in the SER, utilizing enzymes referred to as elongases. Although elongation can also take place in the mitochondria, this is typically for fatty acids shorter than 16 carbons, while the SER focuses on longer chains.
In contrast, the rough endoplasmic reticulum (RER) is studded with ribosomes and is primarily involved in protein synthesis for the cell membrane or for secretion. The mitochondria, Golgi apparatus, and cytosol also play important roles in various cellular functions, but the synthesis of triglycerides specifically occurs in the SER.