The endoplasmic reticulum is an organelle which is a network of membranous tubules present within the cytoplasm of a eukaryotic cell. The endoplasmic reticulum is usually present attached to the Golgi apparatus. There are two types of Endoplasmic reticulum :
1. Smooth endoplasmic reticulum (SER) - Used in the synthesis of lipids and fats
2. Rough endoplasmic reticulum (RER) - RER contains ribosomes that help in the synthesis of proteins.