What organelle in the liver helps in the synthesis of lipid compounds?

The smooth endoplasmic reticulum (Smooth ER) is the organelle in the liver responsible for the synthesis of lipid compounds. This organelle plays a critical role in the production of phospholipids, cholesterol, and various lipids that are essential for building cell membranes and producing steroid hormones.

In liver cells, the smooth ER is particularly abundant, reflecting its significant involvement in metabolism and detoxification processes. Unlike the rough ER, which is studded with ribosomes and primarily involved in protein synthesis, the smooth ER lacks ribosomes and focuses on lipid metabolism and detoxification of harmful substances. This distinction highlights the specialized functions of different types of endoplasmic reticulum within cells.

Considering this, the other organelles listed do not perform the same function regarding lipid synthesis. The Golgi apparatus is involved in modifying, sorting, and packaging proteins and lipids for secretion or delivery to other organelles. Mitochondria are primarily responsible for energy production through cellular respiration, not lipid synthesis. The rough ER, while involved in synthesizing proteins, does not contribute to the production of lipid compounds.