AEMCA Practice Exam

Which component of the cell is involved in the synthesis of lipids?

1. Rough endoplasmic reticulum

2. Smooth endoplasmic reticulum

3. Cell membrane

4. Peroxisomes

The correct answer is: Smooth endoplasmic reticulum

The smooth endoplasmic reticulum (SER) plays a crucial role in the synthesis of lipids, including triglycerides and phospholipids. Unlike its counterpart, the rough endoplasmic reticulum, which is studded with ribosomes and primarily involved in protein synthesis, the SER lacks these ribosomes and has a more tubular structure. This unique architecture allows the smooth endoplasmic reticulum to focus on lipid metabolism and the production of steroids, as well as detoxification processes in the cell. Additionally, the smooth endoplasmic reticulum is essential for the storage and release of calcium ions, which are vital for various cellular functions. Its involvement in lipid synthesis is particularly significant in liver and adrenal cells, where large quantities of lipids are produced to meet metabolic demands. While the other options listed have their specific functions — such as the rough endoplasmic reticulum in protein synthesis, the cell membrane in providing structural support and protection, and peroxisomes in breaking down fatty acids and detoxifying harmful substances — none of these structures are primarily dedicated to lipid synthesis like the smooth endoplasmic reticulum. This distinction underscores why the smooth endoplasmic reticulum is recognized as the key component involved in lipid synthesis within the cell.