Final answer:
The rough endoplasmic reticulum (RER) is associated with ribosomes for protein synthesis, and proteins made here are transported by vesicles to other cell areas for further processing. The smooth endoplasmic reticulum (SER), lacking ribosomes, is involved in lipid synthesis and metabolism.
Step-by-step explanation:
The endoplasmic reticulum (ER) is a critical organelle in cells responsible for various functions, including protein synthesis and lipid metabolism. The rough endoplasmic reticulum (RER) is distinguished by its surface being studded with ribosomes, which are directly involved in the synthesis of proteins. These proteins are then transferred into the lumen of the RER where they may undergo modifications before being packaged into transport vesicles.
These vesicles bud off the RER and can then move to other parts of the cell, such as the Golgi apparatus, where they continue the process of modification and sorting to their final destinations. In contrast, the smooth endoplasmic reticulum (SER) lacks ribosomes and is involved in lipid synthesis and the metabolism of carbohydrates, as well as the detoxification of certain compounds.