Florida Biology EOC Practice Test 2025 – 400 Free Practice Questions to Pass the Exam

The primary function of the smooth endoplasmic reticulum (smooth ER) is indeed to detoxify harmful substances. This organelle plays a crucial role in metabolizing and detoxifying drugs and poisons, especially in liver cells where it helps to process substances that could be harmful to the body. The smooth ER is also involved in lipid synthesis, including phospholipids and cholesterol, which are essential for cell membrane integrity and function.

While forming vesicles is an important function of certain cellular structures, it is primarily associated with both the rough endoplasmic reticulum (when linked to protein synthesis) and the Golgi apparatus. Storing ribosomes is incorrect, as ribosomes are produced in the nucleolus and can be found freely floating in the cytoplasm or bound to rough ER, but they are not stored within smooth ER. Building protein molecules is primarily a function of the rough ER due to its ribosome-studded surface, which aids in protein synthesis. Therefore, detoxification stands out as the defining function of the smooth ER in cellular processes.