Endoplasmic Reticulum: a network of thin, folded membranes that helps in the production of proteins and other molecules. There are two types, smooth endoplasmic reticulum or smooth ER and rough endoplasmic reticulum or rough ER.
Smooth ER
- does not have ribosomes on its surface
- involved in chemical reactions that produce lipid components of the cell membrane
- involved in chemical reactions that produce components of hormones
- assists the cell with removing harmful substances
Rough ER
- ribosomes are attached to its surface
- chemical reactions here produce proteins