Endoplasmic Reticulum - BORING - but you really need to pay attention to this
You live or die based upon whether your cells are able to process the chemicals you require to live. Obvious but it is that simple. Well, how do they do that? If you imagine a cell as a factory filled with makers you can imagine that some of those sit on the factory floor and don't just float around. The ER is rather like a factory floor. It is a complex surface inside a cell which gives the systems that make things like proteins and lipids a place to be. It is the scaffolding upon which the chemical factory that is a cell depends.