1. Rough endoplasmic reticulum (RER): This type of ER is studded with ribosomes, giving it a rough appearance under a microscope. The ribosomes attached to the RER are responsible for synthesizing proteins that will be secreted from the cell, incorporated into membranes, or used in other organelles.
2. Smooth endoplasmic reticulum (SER): This type of ER lacks ribosomes, giving it a smooth appearance. It is involved in various functions, including:
* Lipid synthesis: SER synthesizes lipids, such as phospholipids and steroids.
* Detoxification: It helps detoxify harmful substances, such as drugs and alcohol.
* Calcium storage: It stores and releases calcium ions, which are important for muscle contraction and other cellular processes.
