What is the endoplasmic reticulum? What is the difference in roles of the smooth and rough endoplasmic reticulum, and what makes the rough endoplasmic reticulum rough?

The endoplasmic reticulum is located inside the cells. The prefix endo- means inside (endocrine hormones are released inside the body, endovascular procedures are performed inside blood vessels). A reticulum is a network.The photograph of an Australian reticulated pipe and below shows the way its markings form a network across its skin. It's that network of markings that gives it the name "reticulated". The endoplasmic reticulum is located inside the cells. It is the largest organelle in the cell. An organelle is a structure inside the cell that performs a specific function (s). The endoplasmic reticulum is the site of protein synthesis and transport, lipid and steroid synthesis, carbohydrate metabolism and calcium storage. The rough endoplasmic reticulum is made up of sealed sacs with ribosomes on their surface. It's the ribosomes that give the organelle its a rough appearance when it is viewed with a microscope. Ribosomes are the organelles that are responsible for the assembly of proteins. The smooth endoplasmic reticulum is mainly involved in manufacturing lipids, a process that doesn’t require ribosomes.