Final answer:
The smooth endoplasmic reticulum (SER) is the organelle responsible for lipid synthesis in a cell. It is distinguished by its smooth surface, lacking ribosomes, and is involved in the biosynthesis of lipids, carbohydrate metabolism, and detoxification processes. the correct option is a.
Step-by-step explanation:
The site of lipid synthesis in a cell is the smooth endoplasmic reticulum (SER). The SER is involved in the biosynthesis of lipids, including phospholipids and steroids, and it also plays roles in carbohydrate metabolism and detoxification. It is characterized by a lack of ribosomes on its surface, which gives it a smooth appearance. In contrast, the rough endoplasmic reticulum (RER) is associated with protein synthesis because it is studded with ribosomes. While the Golgi apparatus is involved in modifying, sorting, and packaging proteins and lipids for secretion, it is not the site where lipids are synthesized.