Final answer:
The main difference between smooth ER (SER) and rough ER (RER) is that RER has ribosomes on its surface for protein synthesis, while SER is involved in lipid synthesis, calcium storage, and detoxification, without ribosomes attached.
Step-by-step explanation:
The difference between smooth ER and rough ER primarily lies in their structure and function within a cell. Rough ER (RER) is characterized by the presence of ribosomes on its surface, which gives it a 'rough' appearance. These ribosomes are essential for protein synthesis, whereby proteins are made and then transported to their destinations within or outside the cell. The synthesized proteins may be modified within the RER, such as through glycosylation, before being shipped to the Golgi apparatus.
In contrast, smooth ER (SER) lacks ribosomes, resulting in a 'smooth' appearance. This type of ER is involved in several functions including the synthesis of lipids, such as phospholipids and steroid hormones, regulation of cellular calcium levels, metabolism of carbohydrates, and detoxification of certain toxins.
While both forms of ER are essential for cell function, their distinct roles reflect the diversity of processes that are carried out within the cell. The RER focuses on protein synthesis and modification, while the SER has a broader role in lipid synthesis, calcium storage, and detoxification processes.