What is the difference between smooth ER and rought ER?

The main difference between smooth endoplasmic reticulum (smooth ER) and rough endoplasmic reticulum (rough ER) lies in their structure and function. Rough ER is studded with ribosomes on its cytoplasmic surface, giving it a "rough" appearance, and is primarily involved in the synthesis of proteins destined for secretion or for use in membranes. In contrast, smooth ER lacks ribosomes and is associated with lipid synthesis, metabolism of carbohydrates, and detoxification processes. Additionally, smooth ER plays a role in calcium storage and release within the cell.